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1.
Current knowledge on the structural proteins of porcine reproductive and respiratory syndrome (PRRS) virus: comparison of the North American and European isolates 总被引:28,自引:0,他引:28
Summary. Porcine reproductive and respiratory syndrome virus (PRRSV) belongs to the recently recognized Arteriviridae family within the genus Arterivirus, order Nidovirales, which also includes equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), and simian hemorrhagic fever
virus (SHFV). Mature viral particles are composed of an envelope 50–72 nm in diameter, with an isometric core about 20–30 nm
enclosing a linear positive-stranded RNA genome of approximately 15 kb. The virions are assembled by the budding of preformed
nucleocapsids into the lumen of the smooth endoplasmic reticulum and/or Golgi apparatus. The mature virions are then released
by exocytosis. The viral genome contains eight open reading frames (ORFs) which are transcribed in cells as a nested set of
subgenomic mRNAs. The ORF1a and ORF1b situated at the 5′end of the genome represent nearly 75% of the viral genome and code
for proteins with apparent replicase and polymerase activities. The major structural proteins consist of a 25 kDa envelope
glycoprotein (GP5), an 18–19 kDa unglycosylated membrane protein (M), and a 15 kDa nucleocapsid (N) protein, encoded by ORFs 5, 6 and 7, respectively.
The N protein is the more abundant protein of the virion and is highly antigenic, which therefore makes it a suitable candidate
for the detection of virus-specific antibodies and diagnosis of the disease. Four to five domains of antigenic importance
have been identified for the N protein, a common conformational antigenic site for European and North American strains being
localized in the central region of the protein. In cells and virions, both M and GP5 occur in heterodimeric complexes linked by disulfide bonds. The expression products of ORFs 2 and 4 are also incorporated
into virus particles as additional minor membrane-associated glycoproteins designated as GP2 and GP4, with Mr of 29 and 31 kDa, respectively. The structural nature of the ORF3 product, a highly glycosylated protein with an apparent
Mr of 42 kDa, is still being debated, in view of the apparently conflicting data on its presence in virus particles. Nonetheless,
the GP3 of North American and European strains has been shown to be antigenic, providing protection for piglets against PRRSV infection
in the absence of a noticeable neutralizing humoral response. Pigs exposed to the native form of GP5 by means of DNA immunization develop specific neutralizing and protecting antibodies. The GP5 is involved in antigenic variability, apoptosis, and possibly antibody-dependent enhancement phenomena. The GP4 also possesses antigenic determinants that trigger the immune system to produce neutralizing antibodies. Each of the PRRSV
structural proteins carries common and type-specific antigenic determinants that permit the ability to differentiate between
European and North American strains. The potential use of the PRRSV structural proteins in subunit recombinant-type vaccines
is also discussed.
Received August 30, 1999/Accepted September 29, 1999 相似文献
2.
Kaito M Ohba H Chiba J Kohara M Tanaka H Fujita N Gabazza EC Watanabe S Konishi M Adachi Y 《Medical molecular morphology》2006,39(3):136-145
Cell lines (2.2.15 cells) capable of supporting the replication of hepatitis B virus (HBV) DNA and intact viral particles
have been established by HBV DNA transfection into HepG2 cells. The purpose of this study was to determine the ultrastructural
morphology of native HBV particles without purification in the culture supernatants and in sera from patients. Electron microscopy
(EM) and immunogold EM of the samples were carried out using polyclonal and monoclonal anti-hepatitis B surface antigen antibodies.
HBV particles in the purified samples from the culture supernatants by density-gradient centrifugation were examined to compare
the morphology with that of unpurified samples. EM and immunogold EM studies demonstrated the presence of Dane particles (41.8 nm
in diameter), cobra-shaped (head diameter, 42.4 nm), and horn-shaped (head diameter, 43.5 nm) particles in the culture supernatants
and in the sera from two patients. The tail of the cobra-like particles had a diameter of 21.0 nm and a length of 214 nm.
The hornlike particles had a long branch 20.1 nm in diameter with a length of 189 nm, and a short branch 21.4 nm in diameter
with a length of 112 nm. The ratio of Dane particles and cobra- and horn-shaped particles in the supernatants was 5 : 4 : 1.
After ultracentrifugation, the cobra- and horn-shaped particles completely disappeared; there were only Dane particles together
with spheres of 22 nm and filaments. In conclusion, this study showed for the first time that the native replicative form
of HBV is cobra- and horn-shaped. 相似文献
3.
Morphology of hepatitis C and hepatitis B virus particles as detected by immunogold electron microscopy 总被引:3,自引:0,他引:3
Kaito M Ishida S Tanaka H Horiike S Fujita N Adachi Y Kohara M Konishi M Watanabe S 《Medical molecular morphology》2006,39(2):63-71
We performed indirect immunogold electron microscopy (EM) for immunological identification and characterization of hepatitis
C virus (HCV). To clarify the morphology of HCV, an indirect immunogold EM of two plasma samples from patients with high HCV
RNA titers was carried out using antibodies specific for the putative HCV envelope protein (E) 1. Spherical virus particles
55–65 nm in diameter with delicate spike projections were detected in the 1.14–1.16 g/ml fractions after sucrose density gradient
centrifugation. Polyclonal and monoclonal antibodies to the putative HCV E1 specifically recognized these particles. In addition,
immunogold EM of the samples was also performed to uncover the morphology of HCV core particles. Spherical particles 33–40 nm
in diameter (average, 37 nm) were detected in the 1.22- to 1.25-g/ml fractions by conventional EM after sucrose density gradient
centrifugation. Immunogold EM using rabbit polyclonal antibody (RR8) specific for the putative HCV core protein and colloidal
gold-labeled goat antirabbit IgG showed binding of the gold particles with RR8. Some of the HCV core particles showed icosahedric
morphology. Optical rotation technique showed that the HCV core particles exhibit sixfold symmetry and that the length of
the regular hexagon side is approximately 20 nm, suggesting that they have an icosahedric structure. Further, the detection
limit of the indirect immunogold EM was evaluated in 11 plasma samples from chronic hepatitis B patients with different degrees
of hepatitis B virus (HBV) DNA titers using antihepatitis B surface antigen antibody. The study showed that the detection
limit of virus using this method is 107 virions/ml. 相似文献
4.
Human papillomavirus 16 major capsid protein L1 (composed of 505 amino acids (aa) including 12 cysteines) assembles by itself into virion-like icosahedral particles (L1-capsids), each of which is dissociated into 72 pentameric capsomeres when intermolecular disulfide bonds are disrupted. To identify the cysteines affecting the bonding and the structural integrity of the L1-capsids, we constructed a series of L1 mutants with substitution of serine for cysteine, which were expressed from recombinant baculoviruses in the insect Sf9 cells. From infected cells, the self-assembled L1-capsid fractions were purified by CsCl-equilibrium centrifugation and examined for velocity sedimentation profiles, for the presence of intermolecular bonding by SDS-PAGE with or without a reducing agent, for morphology under an electron microscope, and for susceptibility to trypsin digestion. Mutants C175S (C at aa 175 was replaced with S) and C185S were sedimented in sucrose-density gradients slightly slower than the wild type (WT) capsids, and mutant C428S stayed near the top as WT-capsomeres did. In the nonreducing SDS gel, where WT-capsids were separated into two bands of L1-trimers and L1-dimers, the C175S-trimer band was not detected, the C185S-dimer band was much less dense, and the C428S-trimer and C428S-dimer bands were not detected. Thus, it seems likely that C175, C185, and C428 are involved in L1 trimerization, in L1 dimerization, and in both, respectively. Morphologically, the C175S, C185S, and C428S fractions appeared to consist mostly of heterogeneous rod-shaped tubules, of smaller spherical particles, and of only capsomeres, respectively, whereas C102S, C229S, and C379S resembled WT. The C161S, C175S, C185S, C229S, C379S, and C428S capsids were more sensitive to degradation caused by trypsin than WT. The results indicate that C175, C185, and C428 are required for the normal assembly of L1-capsids through trimerization and dimerization of L1 bound by the intercapsomeric disulfide bonds between cysteines, and that C161, C229, and C379 are necessary for the integrity of L1-capsids probably through intramolecular bonding. 相似文献
5.
Kaito M Tanaka H Horiike S Fujita N Iwasa M Kobayashi Y Gabazza EC Adachi Y Konishi M Watanabe S 《Medical molecular morphology》2007,40(1):23-28
GB virus C (GBV-C) and hepatitis G virus (HGV) have been proposed as new viruses etiologically implicated in non-B, non-C
hepatitis, but the morphology of these particular virus particles is still unknown, and most cases of non-A to E hepatitis
do not relate to their infections. We tried to visualize virus-like particles (VLPs) in plasma samples from hepatitis B surface
antigen- and antibody to hepatitis C virus (HCV)-negative blood donors with elevated alanine aminotransferase (ALT), and examined
the association of the virus-like particles and the genomes of parenterally transmissible GBV-C/HGV. Twenty-three plasma samples,
13 with elevated ALT levels and 10 with normal ALT values, from blood donors without infections of hepatitis B virus (HBV)
and HCV, were subjected to a 20%–60% sucrose density gradient centrifugation, and virus-like particles were observed by electron
microscopy. GBV-C/HGV RNAs in the plasmas were tested. Virus-like particles were found in the fractions with densities of
1.15–1.16 g/ml from 12 of 13 (92.3%) plasmas with elevated ALT levels and 1 of 10 (10%) normal controls. The ultrastructural
morphology of visualized VLPs was pleomorphic in size and appearance; the majority of the VLPs were 50- to 80-nm spherical
particles with a 35- to 45-nm inner core and 9- to 12-nm-long surface spikelike projections. Rodlike VLPs 50–70 nm in diameter
with a length of 110–160 nm were also observed in the same samples. The incidence of detection of the circulating VLPs was
significantly (P < 0.001) related to elevated ALT levels, but GBV-C/HGV RNAs were detected in none of the plasmas containing the virus-like
particles. Spherical VLPs are detected in HBV- and HCV-negative plasmas significantly correlated with the elevation of ALT,
suggesting that they are implicated in non-B, non-C hepatitis. 相似文献
6.
Summary. Hepatitis A virus (HAV) is less well-characterized than other picornaviruses due to its slow and inefficient replication.
In order to gain a greater understanding of HAV-receptor interactions we have used the recovery of cell-bound, infectious
virus particles to measure the effects of temperature, pH and divalent cations on the binding of HAV to susceptible cells.
Viral attachment to cultured cells proceeded at similar rates between 4 °C and 37 °C, with a slight increase in the total
amount of virus attached at 4 °C. In contrast, both acidic pH and the presence of calcium ions independently caused greater
than 20-fold increases in the cell attachment of infectious HAV diluted in buffered sodium chloride solutions, to a level
approaching that of binding in culture medium, whereas magnesium led to a slight enhancement and zinc had no effect. The increased
levels of binding observed with low temperature, low pH and the presence of calcium coincided with reduced rates of virus
elution under similar conditions, suggesting that these conditions lead to a strengthening of the virus-receptor binding.
The addition of calcium to highly purified HAV in buffered sodium chloride reduced the stability of virus during protracted
incubation at 37 °C, as measured by immunoblotting of capsid proteins. The results suggests that the major effect of calcium
in promoting HAV-receptor interactions is through a direct effect on the conformation of the viral capsid.
Received April 8, 1997 Accepted July 9, 1997 相似文献
7.
S-Methyl methanethiosulfonate (MMTS) is a reagent used to trap the natural thiol-disulfide state of the proteins. The efficiency of trapping mixed disulfides in vivo has been found to be higher for MMTS than for the more commonly used N-ethylmaleimide. MMTS has also been used for studying protein S-nitrosylation and the role of catalytic and structural cysteines on enzyme activities. However, the treatment of a protein with MMTS can potentially generate additional protein disulfide bonds. These results indicate that in vitro MMTS is able to form both intramolecular and intermolecular protein disulfide bonds in addition to dithiomethane adducts. 相似文献
8.
Evidence for a precursor-product relationship between intracytoplasmic A particles and mouse mammary tumour virus cores. 总被引:7,自引:0,他引:7
G H Smith 《The Journal of general virology》1978,41(1):193-200
This report presents evidence which supports a relationship between intracytoplasmic A particles (CAP) and mouse mammary tumour virus (MMTV). Three MMTV-specific antigenic determinants in CAP (MMTV p27, p14 and p10) uere detected by immunodiffusion. No structural proteins of comparable mol. wt. were found in CAP; however, exposure of CAP to trypsin resulted in the cleavage of the CAP structural proteins to MMTV-like polypeptides. This process was accompanied by the preservation of MMTV-specific antigen determinants. Disulphide bonds were necessary for the structural maintenance of CAP. Reducing agents destroyed the organized structure of CAP, whereupon processing of CAP proteins to MMTV-like polypeptides by trypsin was prevented. CAP p82, possessed only MMTV p27 antigenic determinants, while CAP polypeptides p20--18 possessed p10 antigenic determinants. Following processing of CAP structural proteins by trypsin, MMTV-specific p27 antigenic determinants were shifted from CAP p82 to CAP p27; MMTV-p10 antigenic determinants were found with CAP p15--10. These results suggest a model wherein CAP structural proteins are modified by protease during maturation, resulting in the shift of their proteins to sizes consistent with those which have been currently identified as the major internal components of the virion and that this phenomenon is largely predicated on the folding of CAP proteins into the morphologically intact A particle. 相似文献
9.
Limited antigenic variation among recent infectious bursal disease virus isolates from France 总被引:2,自引:0,他引:2
Summary. Seven neutralizing monoclonal antibodies (Mabs) to infectious bursal disease virus (IBDV) were used in an antigen-capture
ELISA for the antigenic characterization of 58 IBDV isolates obtained in France since 1989. Fifty-six isolates exhibited an
antigenic profile which was different from reference strain Faragher 52/70, and similar to French very virulent IBDV strain
89 163 (no binding of two Mabs). Two strains (3.4%), isolated in 1991 and 1994, showed additional antigenic modifications
resulting in suppressed or reduced binding activity of three other Mabs. The two atypical viruses were not re-identified in
field samples subsequently collected, hence showing that antigenic variants of IBDV do not tend to replace the antigenically
dominant 89 163-like strains that have prevailed in France since 1989.
Received March 14, 1997 Accepted June 2, 1997 相似文献
10.
Ultrastructural and physicochemical characterization of the hepatitis C virus recovered from the serum of an agammaglobulinemic patient 总被引:2,自引:0,他引:2
A. Trestard Y. Bacq L. Buzelay F. Dubois F. Barin A. Goudeau P. Roingeard 《Archives of virology》1998,143(11):2241-2245
Summary. Hepatitis C virus (HCV) morphology and physicochemical properties remain unclear because HCV usually circulates in a complexed
form in association with immunoglobulins. In the present work, we were interested in the characterization of HCV particles
derived from the serum of an anti-HCV negative/HCV RNA positive agammaglobulinemic patient suffering from chronic type C hepatitis.
Physicochemical properties of the virus particles were determined by serum centrifugation on a 10 60% isopycnic sucrose density
gradient. HCV RNA quantified by bDNA was found in a major peak at density 1.13 g/ml and in a minor peak at densities 1.05 1.07 g/ml.
By electron microscopy, 45 nm large core-like particles were found at the 1.13 g/ml density while 60 nm large virus-like particles
similar to other members of the Flaviviridae family were visualized at the 1.06 1.07 g/ml densities. This confirms some studies reporting the low density of HCV as compared
to other members of the Flaviviridae family.
Received April 23, 1998 Accepted June 24, 1998 相似文献
11.
The ultrastructure of the Iodamoeba bütschlii cyst from human feces was studied. The glycogen mass appears as a compact dense body in the cytoplasm without any surrounding
membrane. The cytoplasm has no mitochondrion. The nucleus shows a distinct nucleolus filled with electron-dense particles.
On one side of the nucleolus are electron-dense cytoplasmic masses measuring 200–400 nm. The nuclear membrane is two-layered
and shows pores.
Received: 27 August 1997 / Accepted: 13 November 1997 相似文献
12.
Summary. A thermoresistant strain, designated m41, of feline immunodeficiency virus (FIV) was selected after 31 successive passages
of chronically infected IRC4 cells at 41 °C. The wild-type virus (wt) which served as a control was cultivated the same number
of times at 37 °C. In Crandell feline kidney cells (CrFK), the replication of m41 was similar at 37 °C and 41 °C, whereas
wt multiplied only at 37 °C. Furthermore, m41 was more resistant than the wt strain at temperatures ranging from 37 to 56 °C.
Syncytia formation was observed with m41 when the CrFK were incubated at 41 °C whereas neither m41 nor wt produced syncytia
at 37 °C. The level of replication of wt and m41 on feline lymphoid primary cells at 37 °C was similar. In contrast to wt,
m41 was unable to infect bone marrow macrophages. Since one or several mutations in the envelope (env) gene could be involved in changes of cell fusion properties and of cellular tropism, the nucleotide sequence of the env gene derived from wt and m41 respectively was determined. Ten mutations were found in the env gene of m41, thus leading to 9 amino acid modifications in the envelope glycoproteins. These results suggest that structural
modifications of the viral envelope proteins are prerequisites for the replication of a thermoresistant FIV strain at elevated
temperature and are correlated with the newly acquired viral phenotype.
Received March 17, 1998 Accepted June 24, 1998 相似文献
13.
Vaira A. M. Milne R. G. Accotto G. P. Luisoni E. Masenga V. Lisa V. 《Archives of virology》1997,142(11):2131-2146
Summary. An undescribed virus, here named ranunculus white mottle virus, was isolated in Italy from cultivated ranunculus showing
mottle and distortion of leaves. The virus was mechanically transmissible to several herbaceous hosts. In negative stain,
the particles appeared as circularised supercoiled threads 3 nm in diameter of different contour lengths; in some conditions
the circles collapsed to form linear pseudobranched structures 9 nm in diameter. Immunolabeling of thin sections showed that
viral antigen was widely distributed in the cytoplasm of parenchyma cells. The virus was not serologically related to the
morphologically similar tenuiviruses, citrus psorosis-ringspot virus and tulip mild mottle mosaic virus. A major 43 kDa protein
was present in purified preparations and in infected plant tissue, as also was a minor 28 kDa protein, serologically related
to the major one. Nucleic acids extracted from purified particles consisted of at least three RNAs, of approximately 7.5,
1.8 and 1.5 kb, which appeared partly in single- and partly in double-stranded form. Purified preparations, but not viral
RNAs, when mechanically inoculated, were infectious. Host range, tissue tropism, particle morphology and coat protein size
place the virus closest to citrus psorosis-ringspot and tulip mild mottle mosaic viruses. These three viruses in turn show
similarities with the Tenuiviruses and Bunyaviridae.
Received May 5, 1997 Accepted July 9, 1997 相似文献
14.
A. Bolmstedt M. Biller J.-E. S. Hansen J. P. Moore S. Olofsson 《Archives of virology》1997,142(12):2465-2481
Summary. Fucosylated N-linked glycans are important constituents of membrane glycoproteins, owing to their significance as biologically
active ligands for several selectins and their role in modulating protein conformation of viral glycoproteins. The human immunodeficiency
virus type 1 (HIV-1) glycoprotein contains more than 30 different glycan structures but so far fucose was found associated
solely with the innermost GlcNAc of N-linked glycans. In the present report we determined whether fucose units also were linked
to the distal GlcNAc via α(1–3) or α(1–4) linkages in N-linked glycans of gp 120. [3H]-fucose labelled gp 120 was subjected to endoglycosidase F digestion, releasing diantennary complex type N-linked glycans,
but leaving the inner polypeptide-bound carbohydrates, GlcNAc and possibly associated fucose units, intact. Gel filtration
of the digested material revealed that [3H]-fucose label was released from gp 120 by this treatment, indicating presence of peripheral fucose units. Furthermore, [3H]-focuse label was also released by treatment of the labelled gp 120 with an α-L-fucosidase specifically removing fucose
in α(1–3) and α(1–4) linkages. Altogether the results indicated presence of fucose units linked to peripheral GlcNAc of gp 120
N-linked glycans. We have earlier shown that other peripheral carbohydrate determinants, i.e. β(1–4)-galactose on N-linked
glycans, maintain a correct antigenic conformation of gp 120. Using a coupled ELISA system, where changes in antigenic behaviour
of a viral glycoprotein were correlated to stepwise elimination of peripheral monosaccharides from N-linked glycans, we found
that treatment of gp 120 with a pan-specific α-fucosidase as well as an enzyme specific for α(1–3)- or α(1–4)-linked fucose
disclosed a hidden linear epitope situated in the gp 120 C2 region. The effects of the general fucosidase on epitope exposure
was more prominent than those obtained with the enzyme with narrow specificity, suggesting that peripheral and inner fucose
units co-operate in the maintenance of gp 120 conformation.
Accepted July 17, 1997 Received December 3, 1996 相似文献
15.
Y. Nakashima H. Hasuwa Y. Kakita K. Murata A. Kuroiwa F. Miake K. Watanabe 《Archives of virology》1998,143(8):1621-1626
Summary. A temperate phage, named PL-2, was induced from Lactobacillus casei ATCC 27092 by mitomycin C treatment of the cells at exponential growth phase. The phage had an isometric head of 45 nm in
diameter and a flexible, non-contractile tail, 150 nm long and 10 nm wide, with a sharp tip. Along the tail axis, about 40
regularly spaced striae were seen. The phage DNA had complementary cohesive ends. The restriction enzyme map of the DNA was
constructed by using 13 different restriction endonucleases. The size of the DNA was 35.2 kb, 83% in size of that of phage
PL-1 lytic for the same Lb. casei strain.
Received December 10, 1997 Accepted March 26, 1998 相似文献
16.
Summary. The highly conserved encapsidation signal (ɛ) of hepatitis B viral (HBV) pregenomic RNA has been reported as an essential
component for encapsidation and protein priming of HBV polymerase. Here, we report that two HBV ɛ RNA-binding host proteins
(80 and 43 kDa) and a copurifying protein (100 kDa) were purified and characterized by the combined methods of UV cross-linking
analysis with the ɛ RNA and column chromatography. Amino-terminal micro-sequencing showed that 80- and 43-kDa proteins were
identified as the heterodimeric nuclear factor of activated T cells (NF90/NF45) and 100 kDa as a molecular chaperone, the
GRP94. The heterodimeric factor interacted preferentially with the upper-bulge region of HBV ɛ RNA helping the HBV polymerase
bind the lower-bulge region. Using in vitro protein priming analysis, the initial oligonucleotide of the protein-priming product
was deduced as 5′-GAAC-3′, which is the complementary sequence of both regions of DR1 and ɛ in the pregenomic RNA. Previously,
we also proposed that the GRP94 was associated with HBV polymerase in the human liver cell HepG2. These results suggest that
the heterodimeric factor plays an important role in the priming activity of HBV polymerase.
Received June 18, 2001 Accepted November 26, 2001 相似文献
17.
Virus-like particles of calicivirus as epitope carriers 总被引:6,自引:0,他引:6
Summary. The VP60 of rabbit haemorrhagic disease virus (RHDV), when expressed in baculovirus, self-assembles into virus-like particles
(VLP) which are antigenically and immunogenically indistinguishable from native virions. When the N-terminal 30 amino acid
residues of VP60 were deleted and substituted by a well characterized six residue epitope from bluetongue virus capsid protein
VP7 (Btag), the fusion protein retained its ability to self-assemble into VLPs. However, the size of these particles was only
27 nm, compared to 40 nm of VLPs derived from native VP60. The antigenicity of both VP60 and the Btag was retained as evident
from ELISA and Western blot analyses. When Btag was fused at the C-terminus of VP60 without deletion, the fusion proteins
formed VLPs of 40 nm in size and also retained their antigenicity, but the Btag antigenicity appeared weak at this fusion
site.
Received December 9, 1998/Accepted March 19, 1999 相似文献
18.
Identification and characterisation of tomato torrado virus,a new plant picorna-like virus from tomato 总被引:4,自引:3,他引:1
Verbeek M Dullemans AM van den Heuvel JF Maris PC van der Vlugt RA 《Archives of virology》2007,152(5):881-890
Summary. A new virus was isolated from tomato plants from the Murcia region in Spain which showed symptoms of ‘torrado disease’; very
distinct necrotic, almost burn-like symptoms on leaves of infected plants. The virus particles are isometric with a diameter
of approximately 28 nm. The viral genome consists of two (+)ssRNA molecules of 7793 (RNA1) and 5389 nts (RNA2). RNA1 contains
one open reading frame (ORF) encoding a predicted polyprotein of 241 kDa that shows conserved regions with motifs typical
for a protease-cofactor, a helicase, a protease and an RNA-dependent RNA polymerase. RNA2 contains two, partially overlapping
ORFs potentially encoding proteins of 20 and 134 kDa. These viral RNAs are encapsidated by three proteins with estimated sizes
of 35, 26 and 23 kDa. Direct protein sequencing mapped these coat proteins to ORF2 on RNA2. Phylogenetic analyses of nucleotide
and derived amino acid sequences showed that the virus is related to but distinct from viruses belonging to the genera Sequivirus, Sadwavirus and Cheravirus. This new virus, for which the name tomato torrado virus is proposed, most likely represents a member of a new plant virus
genus. 相似文献
19.
Summary. Analysis of the preS1 gene of hepatitis B virus was used to define two nosocomial outbreaks of HBV infection. In an outbreak
in an oncology unit we had previously shown by single stranded conformational polymorphism (SSCP) analysis of a 189 bp fragment
of the preS1 gene, that 52 children were infected with HBV strains that displayed only 5 different SSCP profiles. Sequencing
of a 383 bp fragment encompassing the entire preS1 gene, revealed that isolates with same SSCP profile were identical in sequence
across the entire preS1 gene, confirming that those patients with the same SSCP pattern had epidemiologically linked infections.
A second outbreak involved 8 liver transplant patients from two different hospitals, 5 of whom were from the same hospital
at which the oncology outbreak had occurred. Two of these 5 patients had HBV strains that were identical to strains from the
oncology unit and nosocomial transmission probably accounted for the infections in these two, while diversity of both SSCP
profiles and sequence data of remaining 6 patients supported the conclusion that they had not been infected from a common
source. The donor liver is believed to be the most likely source of infection in these patients. HBV isolates from patients
infected in the community were used as a standard for the general degree of preS1 sequence variation of local HBV strains.
Phylogenetic analysis and comparison with reference HBV clones revealed that of 27 local HBV strains, genotypes A and D occurred
most frequently and were identified in 14 and 12 patients respectively, while genotype C was detected in one patient.
Received January 27, 1997 Accepted April 9, 1997 相似文献
20.
Monoclonal antibodies against murine leukemia viruses: identification of six antigenic determinants on the p 15(E) and gp70 envelope proteins. 总被引:27,自引:0,他引:27
Hybrid cells that produced monoclonal antibodies against the envelope proteins of murine leukemia virus (MuLV) were prepared by the polyethylene glycol-mediated fusion of a mouse myeloma cell line with lymphocytes from mice immunized with allogeneic MuLV-producing leukemia cells. Twenty-three independent cell lines were cloned and inoculated into syngeneic mice for the production of ascites fluids that contained high-titered (20–75 mg/ml) monoclonal antibodies. Six serologically distinct specificities were detected when these ascites fluids were tested on a broad panel of MuLV and non-murine retra iruses. Prototype cell lines producing monoclonal antibodies that were representative of each pattern of reaction were selected for further study. In immune precipitation assays each of the prototype antibodies reacted with viral envelope proteins; three of these identified antigenic determinants on p15(E), while three others identified antigenic determinants on gp70. The p15(E) antigenic determinants were shared by a diverse panel of MuLV. One of these p15(E) antigenic determinants was also found in feline leukemia virus. The gp70 antigenic determinants, on the other hand, had a more restricted distribution and were found in only selected isolates of MuLV. 相似文献