bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of BACTEC 9240 Peds Plus medium and isolator 1.5 microbial tube for detection of Brucella melitensis from blood cultures
Authors: Yagupsky P , Peled N , Press J , Abramson O , Abu-Rashid M
Published: January 2020

The sensitivity and time to detection of Brucella melitensis by the BACTEC 9240 and the Isolator blood culture systems were compared in a prospective volume-controlled study. Blood sample aliquots, obtained from children with suspected brucellosis, were inoculated into a BACTEC 9240 Peds Plus bottle and into an Isolator 1.5 Microbial Tube. Overall, 122 pairs of blood samples for culture were obtained, and 28 (23%) were positive by at least one method. The BACTEC 9240 system detected all 28 positive cultures (sensitivity, 100%), and the Isolator system detected 22 positive cultures (sensitivity, 79%) (P = 0.023). Among those 22 cultures positive by both methods, 21 (95%) and 15 (68%) were found to be positive within 3 days by the BACTEC and the Isolator systems, respectively; 8 (36%) were found to be positive at least 1 day earlier by the BACTEC instrument, and the remaining 14 were found to be positive by the two systems on the same day (P = 0.045). The BACTEC 9240 blood culture system is more sensitive than the Isolator system for the detection of B. melitensis and is superior in terms of time to detection of the organism.
Contribution of a typing method based on IS256 probing of SmaI-digested cellular DNA to discrimination of European phage type 77 methicillin-resistant Staphylococcus aureus strains
Authors: Morvan A , Aubert S , Godard C , El Solh N
Published: January 2020

The incidence of infections with phage type 77 methicillin-resistant Staphylococcus aureus (MRSA) strains increased in France in 1987. These strains are widespread in numerous European hospitals. The SmaI restriction profiles of total DNA extracted from 74 phage type 77 MRSA strains isolated from 1987 to 1994 in 10 hospitals in eight European cities (in France, Belgium, and Spain) were analyzed. Hybridization with a probe containing a 468-bp DNA fragment from within the transposase gene of the insertion sequence IS256 was also examined. Forty-three SmaI profiles were detected. Twenty major genotypes were identified, and each genotype contained strains with the same profile or profiles which differed by no more than three bands. Strains isolated in different countries and at several-year intervals were often grouped within the same genotype. A larger number of genotypes could be discriminated by analysis of the patterns of hybridization with the IS256 probe. SmaI restriction fragments with the same apparent electrophoretic mobility could, in some cases, be distinguished by the presence or the absence of nucleotide sequences hybridizing with IS256. The strains that grouped within the same genotype after hybridization with IS256 were mostly those isolated in the same hospital and at less than 12-month intervals. Consequently, the IS256 probe that we used improved restriction profile analysis for discrimination between the intrahospital, outbreak-related phage type 77 MRSA strains and the endemic strains disseminated in various cities and countries.
Detection of human papillomavirus type 16 early-gene transcription by reverse transcription-PCR is associated with abnormal cervical cytology
Authors: Biswas C , Kell B , Mant C , Jewers R J , Cason J , Muir P , Raju K S , Best J M
Published: January 2020

Human papillomavirus type 16 (HPV-16) is associated with abnormal Papanicolou smears, indicative of cervical intraepithelial neoplasia. HPV-16 is the most common genital HPV and is found in up to 40% of young women with normal cervical cytology. In order to investigate whether transcriptionally active HPV-16 infection is associated with abnormal cervical smears, a reverse transcription-nested PCR assay with primers from the E5 open reading frame was developed to detect all HPV-16 early-region mRNA (E-mRNA) transcripts. It was used to study HPV-16-infected women with normal and abnormal cervical cytologies to obtain evidence of active infection. Among HPV-16 DNA-positive women, HPV-16 E-mRNA was detected in 15 of 37 (40.5%) women with abnormal cervical cytology but in only 4 of 35 (11.4%) women with normal cytology (P = 0.007). Thus, HPV-16 E-mRNA transcription is associated with abnormal cervical smears and may have value as a prognostic marker of progressive disease.
Detection of Pneumocystis carinii in respiratory specimens by PCR-solution hybridization enzyme-linked immunoassay
Authors: Ortona E , Margutti P , Tamburrini E , Mencarini P , Visconti E , Zolfo M , Siracusano A
Published: January 2020

By using a recently developed PCR-solution hybridization enzyme-linked assay (PCR-SHELA), we investigated Pneumocystis carinii in bronchoalveolar lavage fluid samples and induced sputa of patients with pneumocystosis. In detecting P. carinii, PCR-SHELA proved more sensitive than immunofluorescence staining or a single PCR and significantly more diagnostically specific than a nested PCR. Our data suggest that PCR-SHELA could be used to detect P. carinii organisms in respiratory samples, particularly in patients with uncertain diagnoses.
The first clinical isolate of Legionella parisiensis, from a liver transplant patient with pneumonia
Authors: Lo Presti F , Riffard S , Vandenesch F , Reyrolle M , Ronco E , Ichai P , Etienne J
Published: January 2020

A bluish white autofluorescent strain of Legionella was isolated from the tracheal aspirate of a female liver transplant patient who developed hospital-acquired pneumonia. This strain had biochemical characteristics compatible with those of L. cherrii, L. anisa, and L. parisiensis and could not be differentiated from L. bozemanii and L. parisiensis by the direct fluorescent-antibody assay. Phylogenetic analysis of partial 16S rRNA gene sequences of this strain (ATCC 700174) revealed the closest homology to the species L. parisiensis (99.5%). An L. parisiensis species-specific profile was also identified by a random amplified polymorphic DNA technique. This is the first report of L. parisiensis isolation from humans.
An epidemiological study of blood culture isolates of coagulase-negative staphylococci demonstrating hospital-acquired infection
Authors: Burnie J P , Naderi-Nasab M , Loudon K W , Matthews R C
Published: January 2020

We applied pulsed-field gel electrophoresis (PFGE) after SmaI digestion and random amplification of polymorphic DNA (RAPD) analysis with nine oligonucleotide primers to 146 blood culture isolates of Staphylococcus epidermidis and 25 blood culture isolates of Staphylococcus haemolyticus. These were obtained over a 12-month period from patients on the neonatal and hematology units of the Central Manchester Health Care Trust. PFGE demonstrated two clusters of isolates of S. epidermidis (type A and type B) on the neonatal ward and a single cluster (type C) on the hematology unit. Type A was represented by 10 indistinguishable isolates from nine patients, type B was represented by 20 isolates from 14 patients, and type C was represented by 26 isolates from 10 patients. Type A isolates were resistant to chloramphenicol and type C isolates were resistant to ciprofloxacin, mirroring current antibiotic usage. There was no evidence of cross infection due to S. haemolyticus. RAPD analysis, on the basis of a single band difference, produced 58 types of S. epidermidis and 12 types of S. haemolyticus with primer 8 (ATG TAA GCT CCT GGG GAT TCA C; 5' to 3') and 54 types of S. epidermidis and 10 types of S. haemolyticus with primer 9 (AAG TAA GTG ACT GGG GTG AGC G; 5' to 3'). Combining the results confirmed cross infection. Types A, B, and C were concurrently isolated from the hands of the staff of the appropriate unit. Partial control was achieved by withdrawing ciprofloxacin use in the case of the hematology unit and improving hand hygiene in both units.
Differentiation of primary from nonprimary genital herpes infections by a herpes simplex virus-specific immunoglobulin G avidity assay
Authors: Hashido M , Inouye S , Kawana T
Published: January 2020

An immunoglobulin G (IgG) antibody avidity assay which uses protein-denaturing agents and a modification of an enzyme-linked immunosorbent assay have been investigated for their usefulness in distinguishing primary genital herpes simplex virus (HSV) infections from nonprimary infections. Forty-nine serum specimens from patients with primary, recurrent, and nonprimary first-episode genital herpes were studied. The clearest separation was obtained with 6 M urea treatment, giving mean avidity indices of 0.398 for sera < or = 100 days after the infection and 0.879 for sera > 100 days after the infection (P < 0.001). No significant difference in avidity indices was observed between the recurrent and nonprimary first-episode infections. Determination of the avidity of HSV-specific IgG will improve the diagnostic potential of HSV serology.
Monoclonal antibodies capable of distinguishing epizootic from enzootic varieties of subtype 1 Venezuelan equine encephalitis viruses in a rapid indirect immunofluorescence assay
Authors: Roehrig J T , Bolin R A
Published: January 2020

We used previously characterized murine monoclonal antibodies to develop a panel useful in subtyping Venezuelan equine encephalitis (VEE) viruses by an indirect fluorescent antibody assay. This panel worked well with either prototype VEE viruses or a series of more recent VEE virus isolates. The panel is particularly useful for rapidly differentiating VEE viruses with epidemic-epizootic potential from other endemic varieties of this virus. Using this panel, we identified an antigenic variant of prototype VEE subtype 1E virus currently present in Mexico. This antigenic change in the E2 glycoprotein was confirmed by enzyme-linked immunosorbent assay. Because VEE virus virulence has been associated in part with the E2 glycoprotein, this observed antigenic change in the 1E virus E2 glycoprotein may explain the apparent equine virulence of this unusual VEE 1E virus.
Heterogeneity and clonality among isolates of Mycobacterium kansasii: implications for epidemiological and pathogenicity studies
Authors: Alcaide F , Richter I , Bernasconi C , Springer B , Hagenau C , Schulze-Röbbecke R , Tortoli E , Martín R , Böttger E C , Telenti A
Published: January 2020

The reservoir and transmission route of Mycobacterium kansasii are largely unknown. In addition, culturing of M. kansasii from human sources is not proof of disease because it may represent colonization rather than infection. Unfortunately, investigation of the epidemiology and pathogenicity of M. kansasii is complicated by evidence of heterogeneity within the species. A comprehensive study by detailed genotypic analysis of a large collection of M. kansasii isolates (n = 276) from various geographical sources within Europe was conducted. Five defined subtypes of M. kansasii were identified; of these subtypes, type I represents the most common isolate from humans. Although phylogenetic analysis confirmed its relationship to the other M. kansasii types, significant sequence divergence was found at the 16S-23S intergenic spacer. Analysis of the chromosomal polymorphism of type I demonstrated a marked clonal structure for this particular organism. Because M. kansasii is becoming a significant pathogen among immunodeficient hosts, future epidemiological and pathogenicity studies should take into consideration both the heterogeneity within the species and the apparent clonality of the most prevalent M. kansasii isolates infecting humans.
Mycobacterium growth indicator tube testing in conjunction with the AccuProbe or the AMPLICOR-PCR assay for detecting and identifying mycobacteria from sputum samples
Authors: Ichiyama S , Iinuma Y , Yamori S , Hasegawa Y , Shimokata K , Nakashima N
Published: January 2020

We have compared the ability of the Mycobacterium Growth Indicator Tube (MGIT) system, a new culture method with an oxygen-sensitive fluorescent sensor, to recover mycobacteria from sputum samples with the abilities of egg-based medium and the Septi-Chek AFB system. We have also assessed the clinical utility of the AccuProbe or the AMPLICOR-PCR assay to directly identify Mycobacterium tuberculosis complex and M. avium-M. intracellulare complex (MAC) from positive MGITs. From 382 sputum samples, 99 isolates of M. tuberculosis complex and 20 isolates of MAC were recovered. The MGIT system had the highest recovery rates for M. tuberculosis complex (97.0%) and MAC (100%), compared to recovery rates of 51.5 and 65.0%, respectively, with the egg-based medium and 81.8 and 85.0%, respectively, with the Septi-Chek AFB system. The shortest recovery times were also achieved with the MGIT system: 16.6 days for M. tuberculosis complex and 12.0 days for MAC, compared to 27.1 and 20.1 days, respectively, with the egg-based medium and 21.4 and 13.2 days, respectively, with the Septi-Chek AFB system. The AccuProbe identified 74 (77.1%) of the 96 M. tuberculosis complex-positive MGITs and 17 (85.0%) of the 20 MAC-positive vials. The AMPLICOR system correctly identified 94 (97.9%) of the 96 M. tuberculosis complex-positive MGITs and all 20 MAC-positive vials. Therefore, the MGIT system used in conjunction with the AMPLICOR system is a rapid and sensitive method for detecting and identifying M. tuberculosis complex and MAC isolates from sputum samples.
Use of recombinant human antibody fragments for detection of cytomegalovirus antigenemia
Authors: Williamson R A , Lazzarotto T , Sanna P P , Bastidas R B , Dalla Casa B , Campisi G , Burioni R , Landini M P , Burton D R
Published: January 2020

The determination and quantitation of peripheral blood leukocytes (PBLs) expressing human cytomegalovirus (HCMV) antigens is widely employed in clinical virology for rapid diagnosis of HCMV-related infections. We describe how CMV antigenemia may be accurately detected by means of human recombinant monoclonal Fab fragments rescued from a combinatorial phage display library prepared from an HCMV-infected donor. Fourteen recombinant Fabs were tested against HCMV-positive PBLs from a patient with ongoing HCMV infection. Three clones were found to react specifically with the nuclei of these cells. These three recombinant Fabs were subsequently tested, individually and pooled together, against 60 PBL samples taken from immunosuppressed patients. The reactivity observed was comparable to that obtained with mouse monoclonal antibodies commercially available for this purpose. The three recombinant Fabs were shown to react specifically with the 65-kDa viral tegument phosphoprotein encoded by UL83 (pUL83), which is the most abundant viral antigen in HCMV-infected PBLs.
PCR amplification and comparison of nucleotide sequences from the groESL heat shock operon of Ehrlichia species
Authors: Sumner J W , Nicholson W L , Massung R F
Published: January 2020

Degenerate PCR primers derived from conserved regions of the eubacterial groESL heat shock operon were used to amplify groESL sequences of Ehrlichia equi, Ehrlichia phagocytophila, the agent of human granulocytic ehrlichiosis (HGE), Ehrlichia canis, Bartonella henselae, and Rickettsia rickettsii. The groESL nucleotide sequences were less conserved than the previously determined 16S rRNA gene sequences of these bacteria. A phylogenetic tree derived from deduced GroEL amino acid sequences was similar to trees based on 16S rRNA gene sequences. Nucleotide sequences obtained from clinical samples containing E. equi, E. phagocytophila, or the HGE agent were very similar (99.9 to 99.0% identity), and the deduced amino acid sequences were identical. Some divergence was evident between nucleotide sequences amplified from samples originating from the United States (E. equi and the HGE agent) and sequences from the European species, E. phagocytophila. A single pair of PCR primers derived from these sequences was used to detect E. chaffeensis and HGE agent DNA in blood samples from human patients with ehrlichiosis.
Maxillary sinusitis caused by Pleurophomopsis lignicola
Authors: Padhye A A , Gutekunst R W , Smith D J , Punithalingam E
Published: January 2020

An immunocompetent 59-year-old man developed sinusitis over a 6- to 8-month period after cutting down a rotted maple tree (Acer sp.). A polypoid obstruction with a bloody drainage was evident in his right nasal cavity. A computed tomographic scan showed an opacification of the maxillary sinus. Surgery was performed to remove a fungus ball that had extended into the patient's medial sinus cavity. Sections of the sinonasal mucosa revealed marked acute and chronic sinusitis with inflammation, congestion, and hemorrhage. Sections from the pasty brown to black debrided material revealed a fungus ball consisting of an extensive network of brown-pigmented, septate, profusely branched hyphae. When grown on oat agar, the phaeoid fungus produced pycnidia and was identified as Pleurophomopsis lignicola. The genus Pleurophomopsis includes seven species, which are all known from plant material. This report documents for the first time a coelomycetous fungus, P. lignicola, causing sinusitis in an immunocompetent patient.
Identification of a new strain of fastidious enterovirus 70 as the causative agent of an outbreak of hemorrhagic conjunctivitis
Authors: Shulman L M , Manor Y , Azar R , Handsher R , Vonsover A , Mendelson E , Rothman S , Hassin D , Halmut T , Abramovitz B , Varsano N
Published: January 2020

A 1994 outbreak of acute hemorrhagic conjunctivitis in Israel was caused by an enterovirus 70 strain that was distinct from previously reported strains. Characterization was by electron microscopy (eye washes), reverse transcription-PCR (RT-PCR; eyewash, specimens, eye swabs, and tears), and sequence analysis of RT-PCR-amplified fragments from the 5' noncoding region and VP1.
Evaluation of the AnaeroPack system for growth of anaerobic bacteria
Authors: Van Horn K G , Warren K , Baccaglini E J
Published: January 2020

Growth of anaerobic bacteria in the AnaeroPack (Mitsubishi Gas Chemical America, Inc., New York, N.Y.) anaerobic atmosphere generation systems, both the AnaeroPack jar and pouch and the AnaeroPack in a GasPak jar were considered equivalent to or better than growth obtained in the corresponding GasPak jar or pouch system (Becton Dickinson Microbiology Systems, Cockeysville, Md.) for 89 (86%) of the 103 anaerobes tested. There were a total of 26 discrepancies after 48 h of incubation, with 16 discrepancies unresolved after 96 h of incubation. The AnaeroPack jar and pouch never failed to reduce the anaerobic indicator. The AnaeroPack systems are easy to use and performed at least as well as or better than the BBL GasPak systems for growth of anaerobic bacteria.
Pediatric bacteremia due to Staphylococcus warneri: microbiological, epidemiological, and clinical features
Authors: Buttery J P , Easton M , Pearson S R , Hogg G G
Published: January 2020

Between 1991 and 1995, an apparent high rate of Staphylococcus warneri bacteremias at the Royal Children's Hospital, Melbourne, Victoria, Australia, raised the possibility of a virulent nosocomial strain. In a retrospective review of 30 S. warneri bacteremias in children, organisms were viable and verified in 22 episodes, 12 representing significant bacteremias. Of these 12 episodes, 2 pairs shared chromosomal DNA pulsed-field gel electrophoresis patterns in unconnected patients, dispelling concerns about a single virulent strain.
Prevalence of bacterial resistance to quinolones and other antimicrobials among avian Escherichia coli strains isolated from septicemic and healthy chickens in Spain
Authors: Blanco J E , Blanco M , Mora A , Blanco J
Published: January 2020

Antimicrobial therapy is an important tool in reducing the enormous losses in the poultry industry caused by Escherichia coli infections (colibacillosis). However, resistance to existing antimicrobials is widespread and of concern to poultry veterinarians. Antimicrobial resistance testing of 468 avian E. coli strains isolated in Spain showed very high levels of resistance to trimethoprim-sulfamethoxazole (67%) and the new fluoroquinolones (13 to 24%). As these antimicrobial agents may cause cross-resistance with human enteric pathogens, prudent use of them in veterinary medicine is highly recommended.
Evaluation of spoligotyping in a study of the transmission of Mycobacterium tuberculosis
Authors: Goguet de la Salmonière Y O , Li H M , Torrea G , Bunschoten A , van Embden J , Gicquel B
Published: January 2020

Spoligotyping (for spacer oligotyping) is an easy, economical, and rapid way of typing Mycobacterium tuberculosis complex strains with the DR spacer markers (J. Kamerbeek et al., J. Clin. Microbiol. 35:907-914, 1997; D. van Soolingen et al., 33:3234-3248, 1995). The stability of the markers was demonstrated by showing that all the Mycobacterium bovis BCG strains tested gave the same spoligotyping pattern. None of the 42 atypical mycobacterial strains tested gave a spoligotyping signal, indicating the specificity of the technique for M. tuberculosis complex. The utility of the spoligotyping method was demonstrated by analyzing 106 isolates of M. tuberculosis obtained over 1 year in three Paris hospitals. The results obtained by this technique were compared to those obtained by Torrea et al. (G. Torrea et al., J. Clin. Microbiol. 34:1043-1049, 1996) by IS6110-based restriction fragment length polymorphism (RFLP) analysis. Strains from patients with epidemiological relationships that were in the same IS6110-RFLP cluster were also in the same spoligotyping group. Spoligotyping was more discriminative than RFLP analysis for strains with one or two copies of IS6110. RFLP analysis did not discriminate between the nine strains with one or two IS6110 bands with no known epidemiological relation, whereas spoligotyping distinguished between eight different types. IS6I10-RFLP analysis split some of the spoligotyping clusters, particularly when the IS6110 copy number was high. Therefore, we propose a strategy for typing M. tuberculosis strains in which both markers are used.
PCR-enzyme-linked immunosorbent assay and partial rRNA gene sequencing: a rational approach to identifying mycobacteria
Authors: Patel S , Yates M , Saunders N A
Published: January 2020

A PCR-enzyme-linked immunosorbent assay (ELISA) for amplification and rapid identification of mycobacterial DNA coding for 16S rRNA was developed. The PCR selectively targeted and amplified part of the 16S rRNA gene from all mycobacteria while simultaneously labelling one strand of the amplified product with a 5' fluorescein-labelled primer. The identity of the labelled strand was subsequently determined by hybridization to a panel of mycobacterial species-specific capture probes, which were immobilized via their 5' biotin ends to a streptavidin-coated microtiter plate. Specific hybridization of a 5' fluorescein-labelled strand to a species probe was detected colorimetrically with an anti-fluorescein enzyme conjugate. The assay was able to identify 10 Mycobacterium spp. A probe able to hybridize to all Mycobacterium species (All1) was also included. By a heminested PCR, the assay was sensitive enough to detect as little as 10 fg of DNA, which is equivalent to approximately three bacilli. The assay was able to detect and identify mycobacteria directly from sputa. The specificities of the capture probes were assessed by analysis of 60 mycobacterial strains corresponding to 18 species. Probes Avi1, Int1, Kan1, Xen1, Che1, For1, Mal1, Ter1, and Gor1 were specific. The probe Tbc1 cross-hybridized with the Mycobacterium terrae amplicon. Analysis of 35 strains tested blind resulted in 34 strains being correctly identified. This method could be used for rapid identification of early cultures and may be suitable for the detection and concurrent identification of mycobacteria within clinical specimens.
Albumin Enhances the Rate at Which Coxsackievirus B3 Strain 28 Converts to A-Particles
Authors: Carson Steven D. , Cole Andrew J.
Published: January 2020

A factor other than the virus receptor expressed by target cells has been found to accelerate the loss of an enterovirus (CVB3/28) infectious titer, with little effect on nearly identical mutant strains. The destabilizing factor in fetal bovine serum, identified as albumin, does not interfere with the catalytic activity of soluble receptor at saturating receptor concentrations and amplifies the catalytic activity of the soluble receptor at a concentration that otherwise produces about one-third the saturated receptor-catalyzed rate of virus decay. This finding evidences the possibility that other virus-“priming” ligands may also be nonessential activating cofactors that serve to accelerate receptor-catalyzed viral eclipse.
Simian Virus 40 Transformation and the Period of Cellular Deoxyribonucleic Acid Synthesis
Authors: Todaro George J. , Green Howard
Published: January 2020

The antiviral agents interferon and statolon protected cells of the mouse line 3T3 against the transforming effect of simian virus 40. Loss of ability of these agents to protect when added some time after infection indicated that the transformation was already fixed. The cells of exponentially growing cultures became resistant to the protective effect of interferon at a linear rate after infection; after one cell generation, the whole population was resistant. By use of synchronous cultures, it was shown that, in cells passing though the G-1 period of the growth cycle, the transformation did not pass the interferon-sensitive stage, whereas cells in
S
[the period of cellular deoxyribonucleic acid (DNA) synthesis] readily passed this stage (i.e., became interferon-resistant). An irreversible step in transformation appeared to occur in cells synthesizing DNA, and it seems likely that replicating cellular DNA was the target of the viral action.
Ribonucleic Acid Polymerase Catalyzing Synthesis of Double-stranded Arbovirus Ribonucleic Acid
Authors: Martin E. M. , Sonnabend J. A.
Published: January 2020

The large-particle fraction from the cytoplasm of chick embryo fibroblasts infected with Semliki Forest virus was found to catalyze the incorporation of the 5′-triphosphates of guanosine, adenine, cytidine, and uridine into an acid-insoluble alkali-labile product. The conditions affecting the preparation and assay of this enzyme were investigated. The ribonucleic acid (RNA) polymerase was not present in uninfected cells, and it appeared in infected cells at the time of rapid viral RNA synthesis. The polymerase was found to catalyze the synthesis of a species of RNA which was resistant to ribonuclease and which exhibited the sedimentation properties, buoyant density, and thermal transition temperature of the double-stranded RNA found in vivo in chick cells infected with Semliki forest virus. Attempts to demonstrate that the reaction product of this enzyme also included single-stranded viral RNA were not successful. Although other interpretations are possible, these results give some support to the suggestion that more than one enzyme may be involved in the replication of viral RNA.
Purification and Properties of Reovirus Ribonucleic Acid
Authors: Iglewski W. J. , Franklin R. M.
Published: January 2020

NaClO
4
was employed in a technique for the rapid extraction of reovirus ribonucleic acid (RNA). The extracted RNA, which was purified in a Cs
2
SO
4
equilibrium density gradient, had a buoyant density of 1.61 g/cm
3
and a sedimentation coefficient of 15
S
in a 7 to 20% sucrose gradient. It was 90% resistant to ribonuclease in a solution of high ionic strength (0.1
m
NaCl). The sensitivity of reovirus RNA to ribonuclease increased with decreasing ionic strength. The thermal denaturation transition of the RNA began at 78 C and was complete at 85 C. The
T
m
of the transition was 81 C in 0.01
m
tris(hydroxymethyl)aminomethane buffer (
p
H 7.2) containing 0.001
m
ethylenediaminetetraacetate. Thermal denaturation of reovirus RNA resulted in the formation of three ribonuclease-sensitive fractions. Denaturation at 25 C in the presence of dimethyl sulfoxide resulted in the formation of two ribonuclease-sensitive fractions.
Electron Microscopic Study of the Development of Simian Virus 40 by Use of Ferritinlabeled Antibodies
Authors: Oshiro Lyndon S. , Rose Harry M. , Morgan Councilman , Hsu Konrad C.
Published: January 2020

An electron microscopic study of simian virus 40 has revealed a number of structural changes that are related to the development of the virus. The presence of viral antigens in both the nucleus and the cytoplasm has been demonstrated by means of ferritin-labeled antibodies. Although cytoplasmic virions are readily tagged, the lack of tagging of nuclear particles presents a perplexing problem. Presumably, the virus, after release from the nucleus, acquires a new antigenic reactivity in the cytoplasm.
Metabolic Properties of Early and Late Vaccinia Virus Messenger Ribonucleic Acid
Authors: Sebring E. D. , Salzman N. P.
Published: January 2020

In vaccinia-infected cells, 60% of the viral messenger ribonucleic acid (mRNA) was associated with polyribosomes, and the remainder sedimented in a broad peak in the 30 to 74
S
region. The quantity of mRNA in polyribosomes was sharply reduced late in the infectious cycle [9 hr postinfection (PI)] to less than 30% of the 2-hr value. However, protein synthesis proceeded at a nearly constant rate from 2 to 13 hr PI. This ability of small quantities of late mRNA to support as much protein synthesis as do the much larger quantities of early mRNA was not due to an increase in stability, since late mRNA decays with a half-life of 13 min, whereas early mRNA has a half-life of 120 min. A similar decrease in viral mRNA synthesis without an accompanying decrease in viral protein synthesis was observed when deoxyribonucleic acid synthesis is inhibited. In contrast to the rapid decay of the late mRNA which was present in polyribosomes, the mRNA which sedimented in the 30 to 74
S
region remained unchanged even after a 2-hr period of exposure to actinomycin. The rate at which infected cells lose the capacity to synthesize specific viral proteins after exposure to actinomycin D was consistent with the half-life values of early and late mRNA that were observed.
Differential Effect of Polyamines on T4 Morphogenesis
Authors: Shalitin Channa , Sarid Sara
Published: January 2020

The 5-fluorouracil (5 FU) technique for the phenotypic reversion of amber mutants was used to demonstrate that under certain circumstances, in the presence of putrescine or spermidine, early mutants have an enhanced response to 5 FU, whereas late mutants have a delayed response. Bacteria infected by T4D wild-type bacteriophage did not produce phage in the presence of high putrescine concentrations. Pulse treatments with putrescine showed that the production of lysozyme depends on a putrescine-sensitive process that begins immediately after infection at 26 C and ends at 36 min or even later. The addition of putrescine at any time during the critical period between 0 and 36 min led to a corresponding delay in lysozyme synthesis after the inhibitor was removed. Intracellular phage maturation was delayed by the addition of 100 μmoles of putrescine per ml. Early enzymes were not affected by the diamine, but the level of phage deoxyribonucleic acid was considerably decreased by the inhibitor. The putrescine-sensitive process that affects the timing of maturation is suggested to be the natural process controlling the T4 “clock.”
Mechanism of Viral Carcinogenesis by Deoxyribonucleic Acid Mammalian Viruses IV. Related Virus-specific Ribonucleic Acids in Tumor Cells Induced by “Highly” Oncogenic Adenovirus Types 12, 18, and 31
Authors: Fujinaga Kei , Green Maurice
Published: January 2020

Formation of hybrids between viral deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) was used to detect virus-specific RNA in the nuclei and polyribosomes of transformed and tumor cells induced by “highly” oncogenic human adenovirus (Ad) types 12, 18, and 31. The presence of virus-specific RNA in the cell nucleus, and the inhibitory effect of actinomycin D on its synthesis, suggest that adenovirus-specific RNA is transcribed from a DNA template in the nucleus. Ad 12, 18, and 31 virus-specific RNA did not hybridize significantly with the DNA of the “weakly” oncogenic adenovirus group (Ad 3, 7, 11, 14, 16, and 21) or with that of nononcogenic Ad 2 and 4. Labeled RNA from Ad 12, 18, and 31 tumor cells hybridized with heterologous Ad 12, 18, and 31 DNA 30 to 60% as efficiently as with homologous DNA. Thus, common viral genes are transcribed in tumor cells induced by Ad 12, 18, and 31.
Nature of Hamster Complement-fixing Antibody to Adenovirus 12 Tumor Antigen
Authors: Fugmann Ruth A. , Sigel M. Michael
Published: January 2020

The presence of complement-fixing (CF) antibody reactive with T antigen and with viral C antigen in hamsters bearing adenovirus 12-induced tumors has been confirmed. Antibody activity in serum obtained at a time when the host was bearing large tumors was found to be associated exclusively with 7
S
immunoglobulins. Two populations of 7
S
immunoglobulins showing CF reactivity were distinguished by electrical charge, as determined by diethylaminoethyl cellulose chromatography and immunoelectrophoresis. No antibodies of the 19
S
IgM type were detected in the serum of hamsters bearing large tumors.
Inhibition of Host Protein Synthesis in Type 5 Adenovirus-infected Cells
Authors: Bello Leonard J. , Ginsberg Harold S.
Published: January 2020

The effect of type 5 adenovirus infection on the synthesis of host-cell proteins by suspension cultures of KB cells was investigated. Although total protein synthesis continued at a constant rate for approximately 36 hr, net synthesis of five host enzymes (lactic dehydrogenase, acid phosphatase, deoxyribonuclease, fumarase, and phosphoglucose isomerase) was found to stop 16 to 20 hr after infection. The synthesis of alkaline phosphatase stopped 9 to 12 hr after infection. The inhibition of host protein synthesis occurred shortly after the synthesis of viral antigens had begun, accounting for the continued synthesis of total protein. An investigation of the relationship between synthesis of viral antigens and inhibition of host protein synthesis yielded results which suggest that the two processes are in some way coupled.
Effect of Actinomycin D on Virus-induced Ribonucleic Acid Polymerase Formation in Foot-and-Mouth Disease Virus-Infected Baby Hamster Kidney Cells
Authors: Polatnick Jerome , Arlinghaus Ralph B.
Published: January 2020

Actinomycin D, at a concentration that inhibits cellular ribonucleic acid (RNA) synthesis, inhibited the production of foot-and-mouth disease virus-induced RNA polymerase in baby hamster kidney cells. Inhibition was proportional to exposure time and reached 85% when actinomycin D was added 90 min before infection. Polymerase production was inhibited to the same extent in growth and minimal media, and the kinetics of its appearance were slightly different than in untreated cells. Enzyme preparations from actinomycin-treated cells having one-third to one-tenth the activity of untreated samples gave products with RNA profiles similar to those of controls. The 37
S
viral peak, 20
S
ribonuclease-resistant peak, and 26 to 28
S
peaks were present in all cases. Actinomycin D did not consistently inhibit virus production in either medium. Insulin did not prevent the actinomycin induced inhibition of polymerase and virus production from occurring.
Isolation and Partial Characterization of Nucleic Acid of Influenza Virus
Authors: Nayak D. P. , Baluda M. A.
Published: January 2020

The principal ribonucleic acid (RNA) component isolated from purified equine influenza virus has an approximate sedimentation coefficient (
S
20,W
) of 21
S
in sucrose gradient containing 0.1
m
NaCl. Three other components of 18
S
, 14
S
, and 8
S
were also detected. All the RNA components have characteristics of single-stranded RNA. The average base composition of the principal RNA components is cytosine, 22.2; adenine, 22.9; guanine, 22.3; and uridine, 32.6. There was no qualitative difference in the RNA isolated from noninfectious virus particles compared to that from infectious virions.
Role of Subunits of 60 to 70
S
Avian Tumor Virus Ribonucleic Acid in Its Template Activity for the Viral Deoxyribonucleic Acid Polymerase
Authors: Canaani Eli , Duesberg Peter
Published: January 2020

Heating the 60 to 70
S
ribonucleic acid (RNA) of Rous sarcoma virus (RSV) destroys both its subunit structure and its high template activity for RSV deoxyribonucleic acid (DNA) polymerase. In comparative analyses, it was found that the template activity of the RNA has a thermal transition of 70 C, whereas the 60 to 70
S
structure dissociates into 30 to 40
S
and several distinct small subunits with a T
m
of 55 C. Analysis by velocity sedimentation and isopycnic centrifugation of the primary DNA product obtained by incubation of 60 to 70
S
RSV RNA with RSV DNA polymerase indicated that most, but perhaps not all, DNA was linked to small (<10
S
) RSV RNA primer. Sixty percent of the high template activity of 60 to 70
S
RSV RNA lost after heat dissociation could be recovered by incubation of the total RNA under annealing conditions. The template activity of purified 30 to 40
S
subunits isolated from 60 to 70
S
RSV RNA was not enhanced significantly by annealing. However, in the presence of small (<10
S
) subunits also isolated from 60 to 70
S
RNA, the template activity of 30 to 40
S
RNA subunits was increased to the same level as that of reannealed total 60 to 70
S
RNA. It was concluded that neither the 30 to 40
S
subunits nor most of the 4
S
subunits of 60 to 70
S
RSV RNA contribute much as primers to the template activity of 60 to 70
S
RSV RNA. The predominant primer molecule appears to be a minor component of the <10
S
subunit fraction of 60 to 70
S
RSV RNA. Its electrophoretic mobility is similar to, and its dissociation temperature from 60 to 70
S
RSV RNA is higher than that of the bulk of 60 to 70
S
RSV RNA-associated 4
S
RNA. The role of primers in DNA synthesis by RSV DNA polymerase is discussed.
Characterization of the Polypeptides Formed in Response to Encephalomyocarditis Virus Ribonucleic Acid in a Cell-Free System from Mouse Ascites Tumor Cells
Authors: Kerr Ian M. , Brown R. E. , Tovell Dorothy R.
Published: January 2020

The polypeptide products synthesized at different times in a cell-free system from Krebs mouse ascites tumor cells in response to the addition of encephalomyocarditis (EMC) virus ribonucleic acid (RNA) were characterized by electrophoresis on polyacrylamide gels and fingerprint analysis of their tryptic peptides. Translation of the EMC RNA genome with time occurred in a nonrandom fashion in these systems, to yield products containing sequences characteristic of both virion capsid polypeptides and EMC-specific polypeptides present only in the infected cell. The molecular weights of the products fell in a series from 20,000 to 140,000 daltons, although occasionally traces of larger polypeptides were also observed. All of the major polypeptides appeared to arise from partial or complete translation of about 60% of the EMC RNA genome. They were not formed by cleavage of a large precursor molecule. It is suggested that they are artifacts generated by premature “termination” of nascent polypeptide chains at preferred sites.
Studies of the Mechanism of Enhancement of Human Adenovirus Infection in Monkey Cells by Simian Virus 40
Authors: Baum Stephen G. , Horwitz Marshall S. , Maizel Jacob V.
Published: January 2020

The defect which prevents human adenovirus replication in monkey cells and the mechanism whereby this restriction is overcome by coinfection with simian virus 40 (SV40) have been studied. Adenovirus capsid proteins are not synthesized efficiently in monkey cells in the absence of SV40. Adenovirus “enhancement” by SV40 was found to be the product of increased efficiency of replication by a small percentage of cells. This enhancement effect apparently occurred only when SV40 and adenovirus infected the same cells. These findings suggest that the replicative block occurs prior to virion assembly, and an accompanying report seeks to locate the site of restriction more precisely at the post-transcriptional level.
Properties of Maedi Nucleic Acid and the Presence of Ribonucleic Acid- and Deoxyribonucleic Acid-Dependent Deoxyribonucleic Acid Polymerase in the Virions
Authors: Lin Fu Hai , Thormar Halldor
Published: January 2020

Maedi virus contains a ribonucleic acid (RNA) which can be resolved into three major components, namely, 62
S
, 33
S
, and 13
S
, by sucrose gradient centrifugation. The presence of RNA- and deoxyribonucleic acid (DNA)-dependent DNA polymerase in virions of maedi virus was demonstrated. The enzyme product could be converted into acid-soluble form by pancreatic deoxyribonuclease, but was resistant to digestion by pancreatic ribonuclease and to hydrolysis by NaOH.
Ribonucleic Acid Species of Intracellular Nucleocapsids and Released Virions of Vesicular Stomatitis Virus
Authors: Kiley Michael P. , Wagner Robert R.
Published: January 2020

Infection of chicken embryo cells with vesicular stomatitis (VS) virus resulted in variable production of three classes of intracellular viral ribonucleocapsids with sedimentation coefficients of approximately 140
S
, 110
S
, and 80
S
, as well as three corresponding classes of released virions designated B, LT, and T. Intracellular nucleocapsids of each class contained three proteins of which the major N protein was firmly bound, and the minor L and NS1 proteins were readily dissociated with 0.5
m
NaCl. The ribonucleic acid (RNA) species extracted from B, LT, and T virions, and from corresponding intracellular nucleocapsids, contained RNA species with approximate molecular weights of 3.2 × 10
6
, 2.0 × 10
6
, and 10
6
, respectively, as determined by polyacrylamide gel electrophoresis. These values are roughly equivalent to sedimentation coefficients of 42
S
, 28
S
, and 23
S
for each of the virion and nucleocapsid RNA species. Cells infected at high multiplicity with undiluted passage VS virus gave rise primarily to virions and nucleocapsids containing 23
S
RNA, whereas cells productively infected with purified B virions produced predominantly B and LT virions and nucleocapsids. At late stages in the productive cycle of infection, more virions containing 42
S
RNA were produced, but the intracellular pool of nucleocapsids containing 28
S
and 23
S
RNA remained relatively constant. Additional studies by more refined techniques are required to test the hypothesis that nucleocapsids containing 28
S
and 23
S
RNA are precursors of the 42
S
RNA in infectious VS-B virions and that production of defective T and LT virions results from failure of ligation of the RNA precursors.
Study of Some Stages of Poliovirus Morphogenesis in MiO Cells
Authors: Ghendon Y. , Yakobson E. , Mikhejeva Angelika
Published: January 2020

Five to seven minutes after addition of
14
C-amino acids to poliovirus-infected MiO cells, radioactivity is found only in 5
S
virus-specific structures. With increased time of labeling, radioactivity appears in considerable amounts also in the 14
S
area. In the presence of guanidine blocking the transition of 14
S
particles in subsequent structures in MiO cells, radioactivity is first detected in the 5
S
zone and then accumulates predominantly in 14
S
particles. These results indicate that formation of 5
S
particles and conversion of a part of their protein into 14
S
particles reflect the earliest stages of the morphogenesis of poliovirus. In contrast to poliovirus-infected HeLa cells, no 73
S
particles could be detected in MiO cells, nor could 73
S
structures be detected in poliovirus-infected MiO cells after a short incubation period (20 to 30 min) with radioactive amino acids, although formation of 150
S
virions was observed. Addition of guanidine to infected MiO cells leads to accumulation of 14
S
particles; however, 73
S
particles are not detected. After removal of guanidine, radioactivity increases only in the 150
S
area. Incubation of 14
S
particles isolated from the sucrose gradient of the cytoplasmic extract of infected MiO cells resulted in formation of 73
S
particles. The results obtained show the modification of the late stages of poliovirus morphogenesis in MiO cells.
Lysogenic Conversion in
Staphylococcus aureus
to Leucocidin Production
Authors: van der Vijver Jan C. M. , van Es-Boon Mary , Michel Marc F.
Published: January 2020

A
Staphylococcus aureus
strain was successively cured of three prophages. A lysogenic conversion by a group A phage to production of Panton-Valentine leucocidin and by a group F phage to staphylokinase production could be demonstrated.
Polyoma Pseudovirions I. Sequence of Events in Primary Mouse Embryo Cells Leading to Pseudovirus Production
Authors: Yelton David B. , Aposhian H. Vasken
Published: January 2020

The relationship of the intracellular events leading to the production of polyoma pseudovirions in primary mouse embryo cells has been investigated. Replication of polyoma deoxyribonucleic acid (DNA) began 18 hr after infection. Assembly of viral capsid protein occurred 12 hr later. Intracellular fragments of host cell DNA, of the size found in pseudovirions, were first detected 36 hr after infection. The amount of intracellular 14
S
host DNA that was produced during infection was seven times greater than the amount of polyoma DNA synthesized. The relative pool sizes of polyoma DNA and 14
S
DNA at the time of virus assembly may dictate the amounts of polyoma virus and pseudovirus produced.
Filamentous Bacterial Viruses IV. Fate of the Infecting Parental Single-Stranded Deoxyribonucleic Acid
Authors: Tseng B. Y. , Hohn B. , Marvin D. A.
Published: January 2020

Some of the infecting fd single-stranded viral deoxyribonucleic acid (DNA) molecules were found to be degraded after having initiated infection. The degradation products were reused for synthesis of DNA, primarily bacterial. Degradation was most extensive when viral DNA was replicating.
Specific Initiation Site for Simian Virus 40 Deoxyribonucleic Acid Replication
Authors: Thoren Marilyn M. , Sebring Edwin D. , Salzman Norman P.
Published: January 2020

Replicating simian virus 40 (SV40) deoxyribonucleic acid (DNA) molecules have been isolated under conditions in which the newly synthesized DNA is uniformly labeled with
3
H-thymidine. These newly synthesized strands are released from the replicative intermediate molecules by alkaline treatment, and it has been possible to isolate single-stranded SV40 DNA which varies in size from 157,000 daltons (from molecules that are 10% replicated) to 1,360,000 daltons (85% replicated). The rates of duplex formation of newly synthesized DNA have been used to relate their genetic complexity to the extent of DNA replication. As DNA replication proceeds, the time required to effect 50% renaturation of the newly synthesized DNA increases at a proportional rate. The data establish that DNA replication is not initiated at random, but rather that there is a single specific initiation site for DNA replication.
Theta Particles: a Structure Found in Hamster Sarcoma Virus
Authors: Albino Anthony P. , deHarven Etienne , Sanders F. Kingsley
Published: January 2020

Hamster sarcoma virus (HaSV), a ribonucleic acid tumor virus, pelleted from tissue culture fluid manifests type C morphology by electron microscopy. However, if virus is first concentrated by polyethylene glycol or ammonium sulfate followed by density gradient banding, the virus shows a dramatically atypical barred core structure, termed “theta particles.” This structure suggests a condensation of the ribonucleoprotein into a flat disc. Atypical particles are found with HaSV and not in similarly treated feline leukemia virus or Rauscher-murine leukemia virus. Differences in the composition of HaSV as compared with these other viruses may be responsible for the production of such particles.