[Cell therapy of critical lower limb ischemia (problems and prospects)]

Critical limb ischemia is a syndrome that combines several peripheral artery diseases with different ethiology and pathogenesis but with similar prognosis, high morbidity and mortality. Possibility of surgical and conservative treatment of critical limb ischemia almost completely exhausted. Some hopes have arisen due to progress in cell technology. The article provides a critical analysis of pathogenic prerequisites of stem/progenitor cells for the treatment of patients with a critical limb ischemia in detail the basic results of preclinical and clinical studies on the safety and efficacy of cell technology. Unsolved problems and prospects of practical application are also discussed.

First Report of Recombinant Potato virus Y Strains in Potato in Jalisco, Mexico

Potato virus Y (PVY) is a serious problem for potato production worldwide. The virus reduces both tuber yield and quality, and recent spread of recombinant strains of PVY in potato production areas is largely credited with the spread of potato tuber necrotic ringspot disease (PTNRD) (1). In Mexico, recombinant strains of PVY were reported in at least two states, Chihuahua (4) and the State of Mexico (3); however, no surveys have been conducted in other potato-producing areas, and the spectrum of PVY isolates circulating in the country has remained uncharacterized. In October 2011, a small-scale survey of seed potato was conducted in the state of Jalisco, Mexico, to identify PVY isolates present in fields. Twelve seed potato fields were inspected visually. These represented various generations of seed potato, from nuclear to G2. Leaf samples were collected from plants displaying mosaic, crinkling, and yellowing symptoms, and were tested for PVY. Fifty samples were collected from cultivars Fabula, Mondial, Fianna, Gigant, Caesar, and Adora. Of the 50 leaf samples collected, seven were PVY-positive using the Immuno-strip Kit (Agdia, Elkhart, IN), and six of these were determined to have a N-serotype according to the typing by the Pocket Diagnostics lateral flow kit (Forsite Diagnostics, Ltd., York, UK). PVY-positive samples came from cultivars Fabula (2 with N serotype), Mondial (4 with N serotype), and Fianna (1 with O serotype). Extracts of the seven PVY-positive leaf samples were applied to Whatman FTA cards (Sigma, St. Louis, MO), dried, and transported to the Plant Virology Laboratory at the University of Idaho for further characterization. All samples immobilized on FTA cards were subjected to RNA extraction and standard reverse transcriptase (RT)-PCR typing using a set of PVY-specific primers (2) to determine the strain type. All PVY isolates were recombinant. The six N-serotype samples were found to contain recombinant PVY^NTN isolates and produced characteristic bands of 181 and 452 bp in RT-PCR, which indicated the presence of two recombination junctions in the HC-Pro/P3 and VPg regions typical of European PVY^NTN isolates. The one O-serotype sample was identified as a recombinant PVY^N-Wi/N:O isolate, and produced 181 and 689 bp bands in RT-PCR, which indicated the presence of one recombination junction in the HC-Pro/P3 region. Sequence analysis of RT-PCR products amplified from five samples with N serotype identified them as PVY^NTN isolates, and from the one with O serotype identified it as PVY^N-Wi/N:O isolate. Sequence comparisons confirmed that N serotype samples contained PVY isolates most closely related to typical PVY^NTN sequences (Accession No. EF026075), while the O serotype sample contained the PVY isolate most closely related to PVY^N-Wi from Europe (HE608963). The data obtained suggest the presence of two different types of PVY recombinants, PVY^NTN and PVY^N-Wi, in seed potato in Jalisco. Additional surveillance for these recombinant isolates may be needed, as well as a survey of their effects on tuber quality in production areas. This is the first report of recombinant isolates of PVY often associated with PTNRD circulating in seed potato in Jalisco, Mexico. References: (1) S. M. Gray et al. Plant Dis. 94:1384, 2010. (2) J. H. Lorenzen et al. Plant Dis. 90:935, 2006. (3) V. R. Ramirez-Rodriguez et al. Virol. J. 6:48, 2009. (4) L. Robles-Hernandez et al. Plant Dis. 94:1262, 2010.

First Report of Grapevine fleck virus in Idaho Grapevines

Idaho has a growing viticulture industry, with nearly 1,600 acres of wine grapes (Vitis vinifera L.). Production is largely concentrated in two locations, the Snake River valley, which includes Canyon County in the southwest, and the Clearwater River valley, primarily Nez Perce County in the northwest. Grapevine fleck virus (GFkV) belongs to the genus Maculavirus, family Tymoviridae, comprising positive-sense, single-stranded RNA viruses with ca. 7.6-kb genome (3). It is one of five non-mechanically transmitted viruses associated with the fleck disease complex and has been previously documented to occur in the neighboring state of Washington (2). Main sources of wine grape nursery material imported to Idaho reside in Washington or in California, and it is important to monitor virus status of the planting material brought to the state. However, no information was available on the occurrence and prevalence of GFkV in wine grapes in Idaho. During three growing seasons in 2009 through 2011, random grapevine samples were collected in 14 vineyards in Canyon, Elmore, Ada, and Nez Perce counties. A total of 434 samples were tested by one step RT-PCR using GFkV-specific primers, GFkVf: 5'-TGACCAGCCTGCTGTCTCTA-3' and GFkVr: 5'-TGGACAGGGAGGTGTAGGAG-3' designed to amplify a fragment of the GFkV capsid protein gene (1). Twenty-four samples tested positive for GFkV by RT-PCR and produced the expected 179-bp DNA fragment. These samples came from five vineyards sampled across all surveyed counties, and represented seven wine grape cultivars, including Pinot Noir, Cabernet Sauvignon, Syrah, Lemberger, Riesling, Chardonnay, Pinot Gris, and one unknown table grape cultivar. Twelve PCR products were cloned into the pGEM-T Easy plasmid vector (Promega), sequenced (numbered ID1 to 12, available upon request), and confirmed to represent fragments of the GFkV CP gene between positions 6,453 and 6,631 in the genome of GFkV isolate MT48 (GenBank Accession No. AJ309022.1). Eight of the Idaho GFkV sequences (ID2, ID3, ID7 to 11, and ID12) matched closely with other GFkV sequences from Washington State, Italy, India, and South America, showing 97 to 99% identity at the nucleotide level in pair-wise comparisons. Four GFkV sequences from Idaho (ID1 and ID4 to 6) showed only modest (90 to 92%) identity in pair-wise comparisons with GFkV sequences available in GenBank. Consequently, in phylogenetic reconstructions eight Idaho GFkV sequences clustered in the same lineage with the six GFkV sequences deposited in GenBank, and four other GFkV sequences were placed outside of this main clade. It is possible that this phylogeny of the Idaho GFkV reflects different sources of the virus-infected planting material brought to the state. In the absence of symptoms expressed in wine grape cultivars infected with GFkV, laboratory methods remain the only tool to detect the virus. To our knowledge, this is the first report of GFkV found in wine grapes in Idaho demonstrating its substantial presence in production areas. References: (1) G. Gambino and I. Gribaudo. Phytopathology 96:1223, 2006. (2) R. A. Naidu et al. Plant Dis. 94:784, 2010. (3) S. Sabanadzovic et al. J. Gen. Virol. 82:2009, 2001.

First Report of Beet severe curly top virus in Jalapeño Pepper in Chihuahua, Mexico

Curly top is a serious problem in many irrigated crops in the semiarid areas in the western United States. The disease is caused by a complex of leafhopper-transmitted curtoviruses, one of which, Beet mild curly top virus (BMCTV), was previously found in chili pepper in Zacatecas and Aguascalientes, Mexico (3). During the past few years, sporadic symptoms similar to curly top disease were observed in jalapeño pepper in the south-central area of Chihuahua State. Symptomatic plants were scattered in otherwise healthy looking pepper stands and displayed stunting and yellowing. Affected leaves were brittle, showed upward curling, and a distinct green vein pattern with interveinal yellowing. In June and August of 2010, field surveys were conducted in Cordillera-Escuadra, Meoqui-Estacion Consuelo, Meoqui-Lomas del Consuelo, and Delicias-Presa Francisco I Madero. Ninety-four leaf samples were collected from symptomatic jalapeño pepper plants and subjected to ELISA and PCR testing for curly top. Of the 94 samples, 11 were found to be positive by triple-antibody sandwich-ELISA with polyclonal antibodies against curly top (2). To confirm the identification of curly top and type the specific curtovirus identified, four ELISA-positive samples were subjected to a PCR analysis using a virus-specific primer set for curtovirus typing designed by Chen et al. (1). All four samples tested produced a single 720-bp band with primers BSCTVv2688 and BGc396 (1) characteristic of the Beet severe curly top virus (BSCTV). These curly top-specific PCR amplicons were sequenced and found to be 99% similar to the BSCTV nucleotide sequence in the C1 gene region (GenBank Accession No. X97203); corresponding sequences were deposited in GenBank under Accession Nos. JF437870 to JF437873. To our knowledge, this is the first report of the curly top virus in the State of Chihuahua, demonstrating that curly top is established and common in jalapeño pepper here and will need surveillance in other vegetable crops under irrigation. References: (1) L. F. Chen et al. Plant Dis. 94:99, 2010. (2) J. Durrin et al. Plant Dis. 94:972, 2010. (3) R. Velásquez-Valle et al. Plant Dis. 92:650, 2008.

Study of the efficiency of transplantation of human neural stem cells to rats with spinal trauma: the use of functional load tests and BBB test

Human ensheating neural stem cells of the olfactory epithelium were transplanted to adult male rats immediately after contusion trauma of the spinal cord at T9 level rostrally and caudally to the injury. Voluntary movements (by a 21-point BBB scale), rota-rod performance, and walking along a narrowing beam were monitored weekly over 60 days. In rats receiving cell transplantation, the mean BBB score significantly increased by 11% by the end of the experiment. The mean parameters of load tests also regularly surpassed the corresponding parameters in controls. The efficiency of transplantation (percent of animals with motor function recovery parameters surpassing the corresponding mean values in the control groups) was 62% by the state of voluntary motions, 37% by the rota-rod test, and 32% by the narrowing beam test. Morphometry revealed considerable shrinking of the zone of traumatic damage in the spinal cord and activation of posttraumatic remyelination in animals receiving transplantation of human neural stem cells.

First Identification of an Unusual Recombinant Potato virus Y Strain in Potato in Mexico

Potato virus Y (PVY) has been reported in potato crops in Mexico (3), with tobacco necrotic variants found in the central State of Mexico (4). Nevertheless, many individual states are currently declared PVY free and distribution of individual strains of PVY in potato in different states of Mexico and in different solanaceous crops had not yet been studied. A limited field PVY survey was conducted on potato in the State of Chihuahua in August 2009. More than 900 random potato leaf samples were collected from cvs. Snowden, Atlantic, FL1867, Felsina, Fianna, Gigant, and Alpha. Seven were found to be PVY-positive and had been collected from cvs. Fianna, Snowden, and FL1867. The PVY status of the collected samples was initially determined with the PVY-specific Immunostrips (Bioreba, Reinach, Switzerland) and by double-antibody sandwich-ELISA using the polyclonal PVY detection kit (Agdia, Elkhart, IN). To determine the strain specificity of these PVY isolates following ELISA tests, the infected original samples were inoculated onto tobacco plants at the four-leaf stage and symptom appearance and development were observed for 8 weeks side-by-side with control isolates PB-Oz (PVY^O), N4 (PVY^NTN), and Mont (PVY^N) (1), followed by the standard PVY strain typing by reverse transcription (RT)-PCR (2). Only one of the PVY-positive samples, originally from symptomless potato cv. Fianna, induced systemic PVY infection in tobacco by producing stunting, mosaic, and vein clearing. No systemic vein necrosis, characteristic of isolates Mont and N4, was observed in Nicotiana tabacum cvs. Burley, Xanthi, or Samsun after inoculation with this isolate during all 8 weeks of observation. This isolate, PVY-M3, was typed as a PVY recombinant by RT-PCR, with two recombinant junctions characteristic of European PVY^NTN strains (2). It was further analyzed by triple-antibody sandwich-ELISA using four PVY^O and PVY^N strain-specific monoclonal antibodies. Monoclonals 1F5 (Agdia) and SASA-N (Scottish Agriculture Science Agency [SASA], Edinburgh) reacted to this isolate and identified PVY-M3 serologically as PVY^N serotype, characteristic of other PVY^NTN recombinants. Monoclonals MAb2 (Agdia) and SASA-O (SASA), specific to PVY^O and PVY^C strains, did not react to PVY-M3. Taken together, the combination of biological, serological, and molecular characteristics define this recombinant isolate from Mexico as belonging to the same PVY strain group represented by the isolate PVY-L26 (1). To our knowledge, this is the first report of such an unusual PVY^NTN recombinant strain from Mexico. Presence of this isolate, with no vein necrotic symptoms induced on tobacco and with PVY^NTN genome, will necessitate development of new detection methods for the seed potato industry in Mexico. References: (1) X. Hu et al. Virus Res. 143:68, 2009. (2) J. L. Lorenzen et al. Plant Dis. 90:935, 2006. (3) L. P. Moreno et al. Rev. Mex. Fitopatol. 22:187, 2004. (4) V. R. Ramirez-Rodriguez et al. Virol. J. 6:48, 2009.

First Report of Grapevine leafroll-associated virus-3 in Six Wine Grape Cultivars in Idaho

In recent years, wine grape (Vitis vinifera) acreage in Idaho has expanded because of favorable climatic conditions for premium wine production. Nearly 95% of the 491.7 ha (1,215 acres) of wine grapes are in the Snake River Valley with Canyon County accounting for 81% of the vines. Previous studies have shown that grapevine leafroll disease (GLD) is the most widespread and economically significant virus disease in wine grapes in Washington and Oregon (1,2). However, little is known about the incidence and economic impact of GLD on wine grapes in Idaho. During the 2008 growing season, leaf samples were collected from approximately 25 individual grapevines of red-berried cultivars (Cabernet Sauvignon, Merlot, Syrah, and Petit Syrah) showing GLD symptoms and white-berried (Chardonnay) cultivars with suspected GLD symptoms growing in 10 geographically separate vineyards in Canyon County. An additional five samples were collected from a Lemberger block in Elmore County. Petiole extracts from these samples were tested by single-tube reverse transcription (RT)-PCR with primers LC 1 (5'-CGC TAG GGC TGT GGA AGT ATT-3') and LC 2 (5'-GTT GTC CCG GGT ACC AGA TAT-3') specific for the heat shock protein 70 homologue (HSP-70 gene) of Grapevine leafroll-associated virus-3 (GLRaV-3) (3). All samples, except the Petit Syrah, produced a single band of the expected size of 546 bp. ELISA with GLRaV-3-specific antibodies (BIOREBA AG, Reinach, Switzerland) confirmed the presence of the virus in samples that were positive in RT-PCR. GLRaV-3-specific amplicons were cloned in pCR2.1 plasmid (Invitrogen Corp., Carlsbad, CA) and 2 to 3 independent clones per isolate were sequenced in both orientations. A pairwise comparison of 22 sequences, six from Chardonnay (GenBank Accessions GQ344810, GQ344811, GQ344823, GQ344824, GQ344825, and GQ344826), five from Cabernet Sauvignon (GQ344807, GQ344808, GQ344809, GQ344827, and GQ344828), four each from Merlot (GQ344815, GQ344816, GQ344817, and GQ344818) and Syrah (GQ344819, GQ344820, GQ344821, and GQ344822), and three from Lemberger (GQ344812, GQ344813, and GQ344814) showed 87 to 100% identity at the nucleotide level and 92 to 100% identity at the amino acid level. A pairwise comparison of HSP-70 sequences of GLRaV-3 isolates from Idaho with corresponding sequences of GLRaV-3 isolates from GenBank showed nucleotide sequence identities between 88% (AJ748519) and 100% (DQ780885). Phylogenetic analysis of HSP-70 sequences from Idaho and GenBank showed clustering of Idaho sequences into five groups, with 12 sequences clustering with a Washington isolate (DQ780885), six sequences in a second group clustering with an isolate from Tunisia (AJ748522), two sequences in a third group clustering with an isolate from Austria (AJ748513), and one sequence each in groups four and five clustering with isolates from Italy (AJ748520) and Washington (DQ780889), respectively. The clustering was not cultivar- or vineyard-specific, suggesting separate introductions of different GLRaV-3 isolates in planting materials. To our knowledge, this is the first report of GLRaV-3 in grapevines grown in Idaho. These and previous results (1,2), indicate the wide distribution of GLRaV-3 in several grapevine cultivars in the Pacific Northwest Region. References: (1) R. R. Martin et al. Plant Dis. 89:763, 2005. (2) R. A. Naidu et al. (Abstr.) Phytopathology 96(suppl.):S83, 2006. (3) M. J. Soule et al. Plant Dis. 90:1461, 2006.

[Problems and prospects of experimental modeling of hypoxy-ischemic lesions in the central nervous system]

Perinatal hypoxy-ischemic brain lesions are one of the main causes of mortality and dysfunction of the central nervous system in the neonatal period accounting for high disability rate among survivors. Numerous animal models were proposed to study this problem in ante-, intra-, and neonatal periods of ontogenesis. This paper is devoted to the analysis of the adequacy of these models. The processes of brain development in laboratory animals are considered along with etiopathogenetic factors that can be reproduced on the models of perinatal hypoxy-ischemic lesions in CNS. The available data on such models and their correspondence to known clinical syndromes are summarized. Current trends in the development of new models of hypoxy-ischemic brain lesions are discussed.

Identification of Potato virus Y Strains Associated with Tuber Damage During a Recent Virus Outbreak in Potato in Idaho

Potato virus Y (PVY) causes substantial losses in potato production by decreasing yields and affecting the quality of potato tubers. Management of PVY in potato is dependent primarily on potato seed certification programs to prevent or limit initial levels of virus inoculum. Prior to 1990, the ordinary strain of PVY (PVY^O) was the predominant virus in North America. PVY^O induces clear foliar symptoms in many potato cultivars, allowing successful management in seed potato through a combination of visual inspections and limited laboratory testing. In recent years, necrotic strains of PVY (PVY^N, PVY^NTN, and PVY^N:O) have begun to spread in the United States, many of which induce mild symptoms in potato, making them more difficult to manage through visual inspections. In addition to reducing yield, necrotic isolates may also cause external and internal damage in tubers of susceptible cultivars, which is known as potato tuber necrotic ringspot disease (PTNRD). Tuber necrotic strains of PVY have been reported across the northern United States (1,2,4), although limited information is available on their incidence and spread in commercial potato production. During June and July of 2007, 38 random samples were collected from three different commercial fields displaying disease problems (cvs. Russet Ranger, Alturas, and Russet Burbank) in the vicinity of Idaho Falls, ID. Plants collected showed various degrees of mosaic and leaf yellowing. By using double-antibody sandwich (DAS)-ELISA and reverse transcription (RT)-PCR, 25 of these plants were identified as PVY positive. The mutiplex RT-PCR assay (3) confirmed that nine plants were infected with PVY^NTN and 11 with PVY^N:O. No RT-PCR products were amplified from five samples. During September and October of 2007, 25 tuber samples (cv. Russet Burbank) showing various degrees of unusual internal symptoms (e.g., brown spots) were collected near Idaho Falls, ID. Twenty-two tubers were found PVY positive by DAS-ELISA, and multiplex RT-PCR determined 13 of those were PVY^NTN, three were PVY^O, one was a PVY^NTN/N:O mixture, and one was a PVY^O/N:O mixture. No RT-PCR products were amplified from four samples. In October 2007, six tubers showing distinct external tuber damage characteristic of PTNRD (cv. Highland Russet) were collected near Twin Falls, ID. All six tubers were determined to be PVY positive by DAS-ELISA, and RT-PCR identified five as infected with PVY^NTN and one with PVY^N:O. All the mixtures were easily separated by inoculating tobacco plants followed by subsequent testing of individual plants. Asymptomatic tubers from the same lot not showing PTNRD damage were found PVY negative by DAS-ELISA and RT-PCR. All PVY^NTN isolates collected during 2007 were inoculated into tobacco plants (Nicotiana tabacum L. cv. Xanthi) and confirmed to induce systemic vein necrosis. Limited sequencing of four of the PVY^NTN isolates determined that they contained recombinant junctions 2 and 3, identifying them as being related to the European strain of PVY^NTN (3). The data suggest an increase in distribution and incidence of necrotic strains of PVY in commercial, potato-production areas in Idaho during an outbreak in 2007 and the potential for an increase in PTNRD. References: (1) P. M. Baldauf et al. Plant Dis. 90:559, 2006. (2) J. M. Crosslin et al. Plant Dis. 90:1102, 2006. (3) J. H. Lorenzen et al. Plant Dis. 90:935, 2006. (4) L. M. Piche et al. Phytopathology 94:1368, 2004.

[Combined treatment including ozonotherapy of patients with viral hepatitis ]

Patients with viral hepatitis have disturbances of biliary tract motor function with the tendency to hypertonus of Oddi's sphincter, changes of physic-colloid properties of bile with increase in density of gall and hepatic bile, pH shift to acid side, microlites formation, disorders in biochemical composition of bile. More than 80% patients have biliar insufficiency. According to our data, with the purpose to correct of disturbances of hepatic exocrine function in patients with viral hepatitis and to prevent stone formation, it is reasonable to use together with antiviral therapy also intravenous injection of ozonated physiological solution and preparations of ursodeoxycholic acid.

Complete nucleotide sequence and genome organization of pineapple mealybug wilt-associated virus-1

Pineapple mealybug wilt-associated virus-1 (PMWaV-1; family Closteroviridae, genus Ampelovirus) belongs to a complex of mealybug-transmissible viruses found in pineapple worldwide. In this study, the complete genome of PMWaV-1 was sequenced and found to be 13.1 kb in length, making it the smallest in the family. The genome encoded seven open reading frames (ORFs) and was unusual for an ampelovirus due to the lack of an intergenic region between the RdRp and p6 ORFs, an ORF encoding a relatively small coat protein (CP), and the absence of an ORF encoding a coat protein duplicate (CPd). Phylogenetic analyses placed PMWaV-1, plum bark necrosis stem pitting-associated virus and some grapevine leafroll-associated viruses in a distinct clade within the genus Ampelovirus.

The complete nucleotide sequence and genome organization of tomato chlorosis virus

The crinivirus tomato chlorosis virus (ToCV) was discovered initially in diseased tomato and has since been identified as a serious problem for tomato production in many parts of the world, particularly in the United States, Europe and Southeast Asia. The complete nucleotide sequence of ToCV was determined and compared with related crinivirus species. RNA 1 is organized into four open reading frames (ORFs), and encodes proteins involved in replication, based on homology to other viral replication factors. RNA 2 is composed of nine ORFs including genes that encode a HSP70 homolog and two proteins involved in encapsidation of viral RNA, referred to as the coat protein and minor coat protein. Sequence homology between ToCV and other criniviruses varies throughout the viral genome. The minor coat protein (CPm) of ToCV, which forms part of the "rattlesnake tail" of virions and may be involved in determining the unique, broad vector transmissibility of ToCV, is larger than the CPm of lettuce infectious yellows virus (LIYV) by 217 amino acids. Among sequenced criniviruses, considerable variability exists in the size of some viral proteins. Analysis of these differences with respect to biological function may provide insight into the role crinivirus proteins play in virus infection and transmission.

Nucleotide sequence and taxonomy of Cycas necrotic stunt virus. Brief report

Cycas necrotic stunt virus (CNSV) is the only well-characterized virus from gymnosperm. cDNA segments corresponding to the bipartite genome RNAs (RNA1, RNA2) were synthesized and sequenced. Each RNA encoded a single polyprotein, flanked by the 5' and 3' non-coding regions (NCR) and followed by a poly (A) tail. The putative polyproteins encoded by RNA1 and RNA2 had sets of motifs, which were characteristic of viruses in the genus Nepovirus. The polyproteins showed higher sequence identities to Artichoke Italian latent virus, Grapevine chrome mosaic virus and Tomato black ring virus, all of which belong to subgroup b of the genus Nepovirus, than to other nepoviruses. Phylogenetic analysis of RNA dependent RNA polymerase and coat protein also showed closer relationships with these viruses than other viruses. The data obtained supported the taxonomical status of CNSV as a definitive member of the genus Nepovirus, subgroup b.

Nucleotide sequence of a Japanese isolate of Squash mosaic virus. Brief report

The complete nucleotide sequence of the RNA-1 of Squash mosaic virus (SqMV) was determined using a Japanese isolate (Y-SqMV). The sequence consisted of 5865 nucleotides excluding the poly (A) at the 3' terminus and contained a single long open reading frame with a coding capacity for a protein of Mr209971. Analysis of the deduced amino acid sequence suggested a genomic organization typical of comoviruses. The nucleotide sequence of the RNA-2 of Y-SqMV was also determined and compared with the SqMV isolates from the United States. The larger and smaller capsid protein (CP) coding region was compared to those of K-SqMV and Z-SqMV, which represent two subgroups of SqMV. The larger CP gene of Y-SqMV showed 93.0% and 88.0% identities with those of K-SqMV and Z-SqMV, respectively at the nucleotide level. The smaller CP gene of Y-SqMV was 94.1% and 88.4% identical with those of K-SqMV and Z-SqMV. The results suggested that the Japanese SqMV isolate (Y-SqMV) is distinct from those in the United States, and might represent a third subgroup.

Satsuma dwarf and related viruses belong to a new lineage of plant picorna-like viruses

Satsuma dwarf virus (SDV) and two closely related viruses, Citrus mosaic (CiMV), and Naval orange infectious mottling (NIMV), seriously affect citrus varieties grown in Japan and East Asia. All three viruses have icosahedral particles built of two proteins encapsidating two single-stranded genomic RNAs. The natural mode of transmission of these SDV-like viruses is unknown, and they were previously placed among tentative members of the family Comoviridae. Recently, a complete genome of SDV was sequenced, and its replication-related proteins were found only distantly related to those of viruses from the family Comoviridae (Iwanami T., Kondo Y., and Karasev A.V. J Gen Virol 80, 793-797, 1999). Here we present a partial genome sequence for another SDV-like virus, NIMV, and a thorough phylogenetic analysis of the gene products encoded by SDV, CiMV, and NIMV to assess their relationships with picorna-like viruses infecting plants, insects, and vertebrates. The RdRp's of SDV-like viruses form a new lineage, separate from members of Como- and Sequiviridae families. Phylogenetic analysis suggests that SDV-like viruses may represent a new family of plant picorna-like viruses. Sequence analysis of the capsid proteins (CPs) encoded by the SDV-like viruses revealed a region of similarity to CPs of animal calici- and picornaviruses that encompasses the structural core of the eight-strand beta-barrel characteristic of picornaviral CPs. These data suggest that SDV and related bipartite viruses evolved separately from the viruses in the family Comoviridae and that the split of an ancestor, monopartite picorna-like virus genome might have occurred more than once.

Differentiation, Distribution, and Elimination of Two Different Pineapple mealybug wilt-associated viruses Found in Pineapple

Surveys for Pineapple mealybug wilt-associated virus-1 (PMWaV-1) and PMWaV-2 were conducted on pineapple samples from Hawaii and around the world. Tissue blot immunoassays (TBIAs) with two different monoclonal antibodies (MAb) specific to either PMWaV-1 or PMWaV-2 indicated that both closteroviruses are widely distributed throughout the pineapple-growing areas of the world. In the worldwide survey, PMWaV-1 was found in 80% of the mea-lybug wilt of pineapple (MWP)-symptomatic and 78% of the asymptomatic pineapple plants tested. A subset of plants was tested for PMWaV-2; 100% of the symptomatic plants and 12% of the asymptomatic plants were positive for this virus. A reverse transcription-polymerase chain reaction (RT-PCR) assay was developed to differentiate between PMWaV-1 and PMWaV-2. Oligonucleotide primers were designed using distinct regions of the HSP 70 homolog genes of the two viruses. PMWaV-specific RT-PCR assays and TBIAs were used to screen the pineapple accessions maintained at the United States Department of Agriculture-Agricultural Research Service National Clonal Germplasm Repository for PMWaV infection; 73% of the accessions were found infected with at least one PMWaV. Pineapple accessions found PMWaV-free were challenged with viruliferous mealybugs to test for immunity to PMWaV-1. No immune germ plasm was identified. Potential alternative virus hosts were screened for infection with virus-specific RT-PCR assays and TBIAs and were also challenged with viruliferous mealybugs. No alternate hosts of PMWaV-1 or PMWaV-2 were identified. PMWaV-1 infection was eliminated through axillary and apical bud propagation from infected crowns. Strategies to manage MWP are discussed.

Sequence diversity and interrelationships among isolates of satsuma dwarf-related viruses

The 3'-region of RNA2 of three viruses (Natsudaidai dwarf virus (isolate ND-1), and two unidentified isolates (LB-1, Az-1)), which were related to Satsuma dwarf virus (SDV), were sequenced. Phylogenetic analysis including the previously reported SDV-related viruses (Citrus mosaic virus (CiMV, Ci-968), Navel orange infectious mottling virus (NIMV, NI-1)) showed that they were classified into three groups, SDV (S-58), CiMV (Ci-968, LB-1, Az-1, ND-1), and NIMV (NI-1). The results suggested these groups might correspond to the three distinct virus species. ND-1, LB-1, and Az-1 were considered strains of CiMV, although they do not induce citrus mosaic on the fruit rind.

Nucleotide sequence, genome organization and phylogenetic analysis of pineapple mealybug wilt-associated virus-2

The genome of pineapple mealybug wilt-associated closterovirus-2 (PMWaV-2) was cloned from double-stranded RNA isolated from diseased pineapple and its sequence determined. The 3'-terminal 14861 nt of the single-stranded RNA genome contains ten open reading frames (ORFs) which, from 5' to 3', potentially encode a >204 kDa polyprotein containing papain-like protease, methyltransferase and helicase domains (ORF1a), a 65 kDa RNA-dependent RNA polymerase (ORF1b), a 5 kDa hydrophobic protein (ORF2), a 59 kDa heat shock protein 70 homologue (ORF3), a 46 kDa protein (ORF4), a 34 kDa coat protein (ORF5), a 56 kDa diverged coat protein (ORF6), a 20 kDa protein (ORF7), a 22 kDa protein (ORF8) and a 6 kDa protein (ORF9). A 132 nt untranslated region was present at the 3' terminus of the genome. This genome organization is typical of the monopartite closteroviruses, including the putative +1 ribosomal frameshift allowing expression of ORF1b. Phylogenetic analysis revealed that within the family CLOSTEROVIRIDAE: the mealybug-transmitted PMWaV-2 is more closely related to other mealybug-transmitted members than to those which are transmitted by aphids or whiteflies. Within this group, PMWaV-2 shares the greatest sequence identity with grapevine leafroll-associated virus-3, another mealybug-transmitted closterovirus.

An engineered closterovirus RNA replicon and analysis of heterologous terminal sequences for replication

Citrus tristeza virus (CTV) populations in citrus trees are unusually complex mixtures of viral genotypes and defective RNAs developed during the long-term vegetative propagation of the virus and by additional mixing by aphid transmission. The viral replication process allows the maintenance of minor amounts of disparate genotypes and defective RNAs in these populations. CTV is a member of the Closteroviridae possessing a positive-stranded RNA genome of approximately 20 kilobases that expresses the replicase-associated genes as an approximately 400-kDa polyprotein and the remaining 10 3' genes through subgenomic mRNAs. A full-length cDNA clone of CTV was generated from which RNA transcripts capable of replication in protoplasts were derived. The large size of cDNA hampered its use as a genetic system. Deletion of 10 3' genes resulted in an efficient RNA replicon that was easy to manipulate. To investigate the origin and maintenance of the genotypes in CTV populations, we tested the CTV replicase for its acceptance of divergent sequences by creating chimeric replicons with heterologous termini and examining their ability to replicate. Exchange of the similar 3' termini resulted in efficient replication whereas substitution of the divergent (up to 58% difference in sequence) 5' termini resulted in reduced but significant replication, generally in proportion to the extent of sequence divergence.

Two paths of sequence divergence in the citrus tristeza virus complex

ABSTRACT Comparison of a sampling of complementary DNA (cDNA) sequences from the Florida citrus tristeza virus (CTV) isolates T3 and T30 to the sequence of the genome of the Israeli isolate VT showed a relatively consistent or symmetrical distribution of nucleotide sequence identity in both the 5' and 3' regions of the 19.2-kb genome. In contrast, comparison of these sequences to the sequence of isolate T36 showed a dramatic decrease in sequence identity in the 5' proximal 11 kb of the genome. A cDNA probe derived from this region of the T36 genome hybridized to double-stranded RNA (dsRNA) of only 3 of 10 different Florida CTV isolates. In contrast, analogous probes from T3 and T30 hybridized differentially to the seven isolates not selected by the T36 probe. Primers designed from cDNA sequence for polymerase chain reaction (PCR) selectively amplified these 10 isolates, allowing them to be classified as similar to T3, T30, or T36. In contrast, individual cDNA probes derived from the 3' terminal open reading frames of the T3, T30, and T36 genomes all hybridized to dsRNA from all Florida CTV isolates tested, and PCR primers designed from the T36 capsid protein gene sequence amplified successfully from all isolates. Based on these data, we propose the creation of two groups of CTV, exemplified by the VT and T36 isolates, respectively. Isolates in the VT group, which include isolates VT, T3, and T30, have genomic sequence divergence that is relatively constant in proportion and distribution throughout the genome, and candidate isolates for that group could be considered strains of the same virus. The T36 group is differentiated from the VT group by the highly divergent 5' genomic sequence. This 5' region of the CTV genome, thus, can serve as a measure of the extent of sequence divergence and can be used to define new groups and group members in the CTV complex.

[A biomechanical study of dental implants using a method for 3-dimensional volumetric mathematical modelling]

Biomechanics of the dental implants introduced into alveoli immediately after tooth extraction has been investigated. The programme ANSYS has been used. Three-dimension volume mathematical models were calculated, with the help of which the tense-deformed state of the supportive biological tissues has been investigated in the area of direct implantation. On the grounds of the results obtained a conclusion has been made that there is an essential improvement of the load distribution under investigation of the inner bone modified biologically designed implants for direct implantation.

Nucleotide sequences and taxonomy of satsuma dwarf virus

The nucleotide sequences of genomic RNA1 (6795 nt) and RNA2 (5345 nt) of satsuma dwarf virus (SDV), a tentative member of the genus Nepovirus, were determined. The deduced genome organization of SDV showed similarities to the organization in como-, faba- and nepoviruses. There is extensive amino acid sequence similarity in the N-terminal regions of the proteins encoded by RNA1 and RNA2, as reported previously only for tomato ringspot nepovirus. However, unlike definitive nepoviruses, which have a single coat protein, SDV has two coat proteins. SDV RNA2 does not contain the long (> 1300 nt) 3' non-coding region characteristic of some nepoviruses. Phylogenetic analysis of SDV RNA polymerase placed SDV apart from como-, faba- and nepoviruses. These unique features suggest that SDV is distinct from the Comovirus, Fabavirus and Nepovirus genera, and needs to be separated into a new genus, probably within the family Comoviridae.

Characterization of the beet yellow stunt virus coat protein gene

ABSTRACT The beet yellow stunt virus (BYSV) genome contains at least nine open reading frames (ORFs) that code for proteins ranging from 6 to 66 kDa. Based on amino acid sequence comparisons, the coat protein (CP) was previously identified as the product of ORF7. We expressed the product of ORF7 in bacteria and confirmed that ORF7 codes for the BYSV CP by immunoblotting. BYSV is a phloem-limited virus, and virus CP antigen of a quality sufficient for diagnostic antisera production has not been available. To produce BYSV antigen free of plant host contaminants, ORF7 was cloned into a pMAL bacterial expression vector. The resulting fusion protein was affinity-purified and used as an antigen to raise anti-BYSV CP antisera in rabbits and guinea pigs. Using these antisera, an indirect double-antibody sandwich (DAS) enzyme-linked immunosorbent assay (ELISA)-based diagnostic system was developed. This indirect DAS-ELISA format enabled reliable detection of BYSV in tissue extracts from virus-infected lettuce diluted up to 5,000 times. The diagnostic system developed may enable large-scale epidemiological studies of BYSV using simple serological techniques. The antisera raised had a titer exceeding 1 x 10(5) in immunoblots and easily detected the 23.7-kDa BYSV CP in virus-infected lettuce and sowthistle plants. In these two plant species, BYSV CP was detected as two closely migrating bands during electrophoresis, which may suggest posttranslational CP modifications. To further characterize the BYSV CP gene, the 5'-untranslated region (UTR) of the BYSV CP subgenomic RNA (sgRNA) was cloned and sequenced. The CP-encoding, approximately 1.9-kb sgRNA has an AT-rich, 66-nucleotide-long 5'-UTR colinear to the genomic sequence upstream of ORF7.

[The enhancement of the efficacy of patient orthodontic treatment based on the mathematical modelling of prospective implant designs]

Opportunities to increase prosthetic treatment efficiency by means of applying osseointegrated implants of traditional and prospective types are analysed. A technique of mathematical modelling of the interaction between implants and jaw bone is exposed. The numerical model and applied program, developed on the basis of finite element method, enabling to analyse a stress strain state of the bone and to determine extreme safe loads on implants are described. It is shown, that the most loaded zone is a layer of the compact bone directly contiguous to the neck of the implant. That is in good agreement with the results of clinical research, according to which just this zone has the highest percentage of complications. Methods for further optimisation of implants and prosthetic structures for the purpose to perfect the techniques of prosthetic treatment are discussed.

[The effect on painful and silent myocardial ischemia of the preparations Efox and Efox Long in patients with stenocardia of effort]

The study of two novel drugs for management of both painful and silent myocardial ischemia isosorbide-5-mononitrate (IS-5-MN), efox, and its long-acting variant efox-long demonstrated that both drugs exerted noticeable antianginal effect at maximal concentration in blood. This was achieved by a single dose and course administration. The differences in the effects of the two dosage forms of IS-5-MN on painless ischemia may be explained by limited coronary reserves of anginal patients.

Modulation of the antigenic reactivity of the citrus tristeza virus coat protein

Trapping properties of a panel of monoclonal antibodies (Mabs) raised against citrus tristeza virus (CTV) were analyzed in an indirect double-antibody sandwich ELISA (I-DAS-ELISA). These antibodies had been previously assigned by serological specificity into five groups (I to V). Mabs from group V, which are directed to conformational epitopes, trapped significant amounts of virus antigen from CTV-infected plant tissue at IgG concentration above 10 ng/ml. Mabs from groups I to IV, which are directed to linear, continuous epitopes, performed poorly as coating antibodies, even at a 1 microgram/ml concentration of the IgG's, indicating that the respective linear epitopes were inaccessible. However, when Mabs from groups I to IV were combined with a small amount of Mabs from group V, a substantial increase in trapping of the CTV antigen was recorded. In this 'two antibody-binding assay' previously cryptic, linear epitopes of the CTV CP apparently became accessible to the Mabs from groups I to IV. Modulation of the antigenic reactivity of the CTV CP was also recorded upon binding of the Mabs directed to the conformational epitopes in solution. Induced exposure of the linear epitopes of the CTV CP was revealed in 'two antibody-binding assays' with pairwise combinations of different mouse Mabs and several rabbit and chicken polyclonal antisera with different serological specificities, including antisera to bacterially expressed CP fragments. This mixed coating in I-DAS-ELISA resulted in substantially increased efficiency of the virus antigen trapping by antisera produced against bacterially expressed protein fragments and an increased sensitivity of the CTV detection after optimization of the ratio between conformational and linear antibodies.

Transcriptional strategy of closteroviruses: mapping the 5' termini of the citrus tristeza virus subgenomic RNAs

Citrus tristeza virus (CTV) induces formation of a nested set of at least nine 3' coterminal subgenomic RNAs (sgRNAs) in infected tissue. The organization and expression of the 19,296-nucleotide (nt) CTV genome resembles that of coronaviruses, with polyprotein processing, translational frameshifting, and multiple sgRNA formation, but phylogenetically the CTV polymerase, like polymerases of other closteroviruses, belongs to the Sindbis virus-like lineage of RNA virus polymerases. Both positive-strand RNA virus supergroups, coronaviruses and Sindbis-like viruses, utilize different mechanisms of transcription. To address the mechanism of CTV transcription, 5' termini for the two most abundant sgRNAs, 1.5 and 0.9 kb, respectively, were mapped by runoff reverse transcription. The two sgRNAs were demonstrated to have 48- and 38-nt 5' untranslated regions (5'-UTRs), respectively. The 5'-UTR for the 1.5-kb RNA was cloned, sequenced, and demonstrated to be colinear with the 48-nt genomic sequence upstream of the initiator codon of the respective open reading frame 10, i.e., to be of continuous template origin. The data obtained suggest that the sgRNA transcription of CTV is dissimilar from the coronavirus transcription and consistent with the transcriptional mechanism of other Sindbis-like viruses. Thus, the Sindbis virus-like mechanism of transcription of the positive-strand RNA genomes might be successfully utilized by the closterovirus genome of up to 19.3 kb with multiple sgRNAs.

Organization of the 3'-terminal half of beet yellow stunt virus genome and implications for the evolution of closteroviruses

The 3'-terminal half of the beet yellow stunt virus (BYSV) genome 10,545 nt, has been cloned and sequenced. The sequenced portion of the BYSV genome encompasses 10 open reading frames (ORFs) and 241 nt of the 3' untranslated region. The sequence spans, in the 5' to 3' direction, the C-terminal region of the replication-associated polyprotein gene (ORF 1a) which includes the set of motifs typical of helicases (HEL), the entire 53-kDa polymerase (RdRp) gene (ORF 1b), and genes encoding 30-kDa (ORF 2), 6-kDa (ORF 3), 66-kDa (ORF 4), 61-kDa (ORF 5), 25-kDa (ORF 6), 23.7-kDa (coat protein, CP) (ORF 7), 18-kDa (ORF 8), and 22-kDa (ORF 9) proteins. The double-stranded RNA "replicative form" of the BYSV was demonstrated to have a nontemplate G residue at the 3' terminus of the (+) strand. The RdRp of BYSV is presumably expressed via a +1 ribosomal frameshift. The five-gene module conserved among closteroviruses was identified in BYSV; it includes a gene array coding for a 6-kDa small hydrophobic protein, a 66-kDa homolog of the cellular HSP70 heat shock proteins, a 61-kDa protein, and a 25-kDa diverged copy of the CP followed by the CP gene itself. Phylogenetic analysis of the replication-associated HEL and RdRp domains as well as proteins from the five-gene module demonstrated the closest relationship between BYSV and two other closteroviruses, beet yellows (BYV) and citrus tristeza (CTV) viruses. Like CTV, the BYSV genome contains a 30-kDa protein gene between the RdRp and the 6-kDa protein genes, and like BYV it has only two genes downstream of the CP gene. The organization of the BYSV genome appears to be intermediate between BYV and CTV, which suggests that these three viruses might represent three distinct but probably close stages in the closterovirus evolution.

Multiple species of defective RNAs in plants infected with citrus tristeza virus

Alemow (Citrus macrophylla) and sweet orange (C. sinensis) plants infected, respectively, with several Israeli and Florida isolates of the citrus tristeza virus (CTV) were found to contain multiple species of RNA molecules with features similar to defective-interfering RNAs. Northern blot hybridizations of dsRNAs extracted from serial passages of the Israeli VT isolate (CTV-VT) and from different plants infected with a single source of inoculum showed considerable variation both in the presence and in the relative abundance of the defective RNA (D-RNA) bands. The D-RNA molecules were found to be encapsidated in the CTV particles. Sequence analysis of two VT D-RNA molecules of 2.7 and 4.5 kb revealed that they were composed of two regions corresponding to 1818 and 4036 nucleotides from the 5' and 938 and 442 nucleotides from the 3' termini of the CTV-VT genomic RNA, respectively. A short (ca. 0.8 kb) nonencapsidated single-stranded positive-sense RNA species was also found in infected plants. This ssRNA, which copurified with dsRNAs, was shown by hybridization to encompass the 5'-terminal part of the CTV genome and might have an extensive secondary structure.

Characterization of citrus tristeza virus subgenomic RNAs in infected tissue

Citrus tristeza virus (CTV) specific RNAs extracted from infected citrus tissue were analyzed by Northern blot hybridization. RNAs were characterized by size and identified using cDNA probes specific to nine open reading frames (ORFs) identified by the analysis of sequence obtained from cDNA clones of the T36 isolate of CTV. Sequence specific cDNA probes identified the genomic RNA as well as subgenomic RNAs representing the p33, p65, p61, p27, p25, p18, p13, p20, and p23 ORFs in extracts of total or double-stranded RNA (dsRNA) isolated from infected tissue. A probe derived from the 3' terminal ORF (p23) hybridized to each of these subgenomic RNAs, indicating that the RNAs are 3' coterminal. The relative amounts of the different subgenomic RNAs varied widely. The RNAs for the p20 and p23 ORFs were the most abundant and surpassed the amount of the p25 or capsid protein specific subgenomic RNA. The number and sizes of the CTV subgenomic RNAs were the same in total RNA and dsRNA preparations. Propagation of T36 in seven different citrus hosts did not alter the pattern of subgenomic RNAs.

Complete sequence of the citrus tristeza virus RNA genome

The sequence of the entire genome of citrus tristeza virus (CTV), Florida isolate T36, was completed. The 19,296-nt CTV genome encodes 12 open reading frames (ORFs) potentially coding for at least 17 protein products. The 5'-proximal ORF 1a starts at nucleotide 108 and encodes a large polyprotein with calculated MW of 349 kDa containing domains characteristic of (from 5' to 3') two papain-like proteases (P-PRO), a methyltransferase (MT), and a helicase (HEL). Alignment of the putative P-PRO sequences of CTV with the related proteases of beet yellows closterovirus (BYV) and potyviruses allowed the prediction of catalytic cysteine and histidine residues as well as two cleavage sites, namely Val-Gly/Gly for the 5' proximal P-PRO domain and Met-Gly/Gly for the 5' distal P-PRO domain. The autoproteolytic cleavage of the polyprotein at these sites would release two N-terminal leader proteins of 54 and 55 kDa, respectively, and a 240-kDa C-terminal fragment containing MT and HEL domains. The apparent duplication of the leader domain distinguishes CTV from BYV and accounts for most of the size increase in the ORF 1a product of CTV. The downstream ORF 1b encodes a 57-kDa putative RNA-dependent RNA polymerase (RdRp), which is probably expressed via a +1 ribosomal frameshift. Sequence analysis of the frameshift region suggests that this +1 frameshift probably occurs at a rare arginine codon CGG and that elements of the RNA secondary structure are unlikely to be involved in this process. The complete polyprotein resulting from this frameshift event has a calculated MW of 401 kDa and after cleavage of the two N-terminal leaders would yield a 292-kDa protein containing the MT, HEL, and RdRp domains. Phylogenetic analysis of the three replication-associated domains, MT, HEL, and RdRp, indicates that CTV and BYV form a separate closterovirus lineage within the alpha-like supergroup of positive-strand RNA viruses. Two gene blocks or modules can be easily identified in the CTV genome. The first includes the replicative MT, HEL, and RdRp genes and is conserved throughout the entire alpha-like superfamily. The second block consists of five ORFs, 3 to 7, conserved among closteroviruses, including genes for the CTV homolog of HSP70 proteins and a duplicate of the coat protein gene. The 3'-terminal ORFs 8 to 11 encode a putative RNA-binding protein (ORF 11), and three proteins with unknown functions; this gene array is poorly conserved among closteroviruses.(ABSTRACT TRUNCATED AT 400 WORDS)

Defective RNA molecules associated with citrus tristeza virus

Preparations of single-stranded (ss) RNA extracted from particles of the Israeli VT strain of citrus tristeza virus (CTV-VT), and ss- and double-stranded (ds) RNA preparations extracted from infected Alemow (Citrus macrophylla) plants, contained a population of molecules with features that suggest that they are defective RNAs. The prototype of 2424 nt was cloned and sequenced and was found to be composed of two genomic regions corresponding to the 5' (1151 nt) and the 3' (1259 nt) termini of the genomic CTV-RNA, with two perfect direct repeats of eight nucleotides of unknown origin at the junction site. Northern hybridization analysis demonstrated that this 2.4-kb defective RNA is an abundant species among the other CTV-specific ss- and ds-RNAs in infected plants. The 2.4-kb RNA was found encapsidated by the CTV coat protein indicating that the CTV origin of assembly is located close to the 5' or 3' terminus. This is the first defective RNA to be reported for a member of the closterovirus group.

Screening of the closterovirus genome by degenerate primer-mediated polymerase chain reaction

The genome of beet yellows virus (BYV), the type representative of the closterovirus group, encodes a homologue of the cellular heat-shock protein (HSP) 70 family. A pair of degenerate primers targeted to motifs A and E, which are highly conserved in HSP70s, was synthesized. Genomes of several definite and possible members of the closterovirus group were screened for the presence of the HSP70 gene with PCR using these degenerate primers. BYV, citrus tristeza virus (CTV), beet yellow stunt virus (BYSV) and carnation necrotic fleck virus templates produced 1 kb amplification products, which were shown by sequencing to represent fragments of the respective HSP70 genes. Further screening was performed with an additional degenerate primer targeted to the motif IV of the putative viral polymerase. This degenerate primer and specific primers complementary to the 5' region of the HSP70 genes of the respective viruses were used to estimate the distance between polymerase motif IV and the start point of the HSP70 gene for BYV (approximately 1.1 kb), CTV and BYSV (around 2.0 kb) by PCR. The amplified genome regions of CTV (3026 nucleotides) and BYSV (2837 nucleotides) were cloned and sequenced. CTV and BYSV were found to encode the gene for an additional 30K (BYSV) or 33K (CTV) protein between the polymerase and the small hydrophobic protein genes, which was absent in BYV. These two 30K proteins displayed very weak similarity to each other, unlike the highly conserved polymerases, hydrophobic proteins and HSP70s of BYV, CTV and BYSV. Degenerate primer-mediated PCR proved to be an efficient tool for rapid screening and subsequent cloning of the viral genomes.

Nucleotide sequence and organization of eight 3' open reading frames of the citrus tristeza closterovirus genome

The citrus tristeza closterovirus (CTV) RNA genome was cloned as cDNA generated from both CTV-specific double-stranded RNA and genomic RNA, and the sequence of the 3' 7292 nucleotides was determined. The sequenced portion contained eight open reading frames potentially encoding, in the 5' to 3' direction, proteins with the apparent molecular weights of 65, 61, 27, 25 (capsid protein, CP), 18, 13, 20, and 23 kDa, and a potential noncoding region of 277 nucleotides. The 65-kDa protein is a viral homolog of cellular hsp70 heat shock proteins (hsp), the 61-kDa protein is distantly related to the hsp90 proteins, and the 27-kDa protein is a diverged copy of the CP. Database searches did not identify any protein sequences of significant similarity to the remaining four ORFs downstream of the CP. A specific four-gene module consisting of the hsp70 protein, the hsp90-related protein, the diverged copy of the CP, and the CP itself was found to be common in organization between CTV and beet yellows closterovirus. All four proteins in this module were highly conserved, indicating that these viruses probably have evolved from a common ancestor.

Coat protein gene duplication in a filamentous RNA virus of plants

Computer-assisted analysis revealed a striking sequence similarity between the putative 24-kDa protein (p24) encoded by open reading frame (ORF) 5 of beet yellows closterovirus and the coat protein of this virus encoded by the adjacent ORF6. Both of these proteins are closely related to the homologous proteins of another closterovirus, citrus tristeza virus. It is hypothesized that the genes for coat protein and its diverged tandem copy have evolved by duplication. Phylogenetic analysis using various methods for tree generation suggested that the duplication was already present in the genome of the common ancestor of the two closteroviruses. The genes for p24 and coat protein of beet yellows closterovirus were cloned, transcribed, and translated in vitro yielding products of the expected size. It was shown that p24 is translated starting from the first of the two alternative AUG codons located near the 5' terminus of ORF5. The presence of a single protein species in beet yellows closterovirus virions and the near identity of the amino acid composition of this protein with the composition of the ORF6 but not the ORF5 product indicated that p24 is not a major virion component. Most of the amino acids that are conserved in the coat proteins of filamentous viruses of plants are retained also in p24. These observations suggest that p24 may share some structural and functional features with the coat protein but probably fulfills a distinct function in virus reproduction.

Poa semilatent virus, a hordeivirus having no internal polydisperse poly(A) in the 3' non-coding region of the RNA genome

RNA from the Hungarian isolate of poa semilatent virus (PSLV) directed in vitro synthesis of 120K, 75K, 25K (coat protein) and 20K polypeptides. In vitro translation of PSLV RNA was blocked by the cap analogue, m7Gpp, thus suggesting that the virus RNA was capped. PSLV RNA could be aminoacylated with [14C]tyrosine in vitro. The sequence of 1.5 kb from the 3' end of the PSLV RNA gamma component revealed two open reading frames (ORFs) separated by a uridine-rich intergenic region. The putative product of the incomplete 5'-proximal ORF showed a close amino acid sequence similarity with the C-terminal segment of the gamma a protein (putative RNA replicase) encoded in the barley stripe mosaic virus (BSMV) RNA gamma, and the 20K product of the 3'-proximal ORF was found to be related to the 17K gamma b product of BSMV. The sequence of 0.8 kb from the 3' end of PSLV RNA beta encompassed two (incomplete) overlapping ORFs whose putative products are related to the beta c and beta d proteins encoded in the similarly arranged ORFs of BSMV RNA beta. Nucleotide sequence homology between the respective parts of the two hordeivirus genomes was restricted to the ORF for gamma a, the spacer between the ORFs for gamma a and gamma b, and the 3' non-coding region, particularly the 95 nucleotide segment at the 3' end representing a tRNA-like structure. Despite limited sequence conservation beyond this segment, the entire 3' non-coding region of PSLV RNA could be folded in a tight pseudoknotted structure closely resembling that of BSMV RNA. Surprisingly, the 'signature' sequence typical for BSMV RNA, internal polydisperse poly(A) intercalated between the coding part of the 3' tRNA-like structure, was not detected in the PSLV genome. Instead, the virus RNA contained several oligoadenylate stretches spaced by other residues, close to the junction of its coding and 3' non-coding portions.

HSP70-related 65 kDa protein of beet yellows closterovirus is a microtubule-binding protein

Beet yellows virus (BYV) genome encodes a 65 kDa protein homologous to the HSP70 family of cellular heat-shock proteins (Agranovsky, A.A., Boyko, V.P., Karasev, A.V., Koonin, E.V. and Dolja, V.V. (1991) J. Mol. Biol. 217, 603-610). The respective gene was cloned and expressed in vitro yielding a product of the expected size (p65). This product was found to bind to the purified microtubules with a binding constant of 4 x 10(-7) M. The binding of p65 was stimulated if ATP presented in the translation mixture was hydrolyzed by apyrase. Removal of the short C-terminal domains of alpha- and beta-tubulin by subtilisin digestion abolished the binding, demonstrating its specificity. The possible role of p65 association with microtubules in the movement of virus within and/or between plant cells is proposed.

Tombusvirus genome may encode the sixth small protein near its 3' terminus

A short open reading frame (ORF), ORF6, potentially encoding a polypeptide (pX) of 32-69 amino acids, was revealed upon computer translation of the 3' terminal regions of tomato bushy stunt, cymbidium ringspot, cucumber necrosis and artichoke mottled crinkle tombusviruses. ORF6 has an initiating AUG codon in a favorable context and is evaluated as expressible, judging the distribution of guanosine residues within the codons. Inspection of the alignment of the four putative products encoded by ORF6 shows statistically significant sequence conservation over 11 SD above the random expectation. Secondary structure predictions based on the Garnier method demonstrate strict conservation of a loop between two beta-strands, thus suggesting functional conservation of pXs. It is suggested that pX is not involved in tombusvirus genome replication and encapsidation in cis.

Expression strategy of the potato virus X triple gene block

The mode of expression of the overlapping genes of the triple block positioned internally in potato virus X (PVX) RNA was examined. The results of In vitro translation of synthetic RNA transcripts and natural PVX-specific methylmercuric hydroxide-denatured dsRNAs suggest that the 25K protein is expressed as a single translation product of the 2.1 kb subgenomic (sg) RNA and that both the 12K and 8K proteins are expressed from the same 1.4 kb sgRNA.

[Newly developed stenocardia: effect of intensive physical training on the indicators of the blood coagulation system and fibrinolysis]

The impact of 6-week strenuous exercise training (SET) on blood coagulative and fibrinolytic parameters (levels of fibrinogen, soluble fibrin, fibrinogen-fibrin degradation products, activities of plasminogen and plasmin) was studied in 28 patients with first angina pectoris, in 16 of whom in the first 3 months of onset of the disease, but angina pectoris lasting 3-4 prior to SET. The 6-week strenuous exercises in patients with first angina were found to cause a decrease in fibrinogen levels, exert no action on thrombin and fibrin formation. They did not diminish plasminogen activator release during exercise in patients with pre-exercise unstable angina.

Putative 65 kDa protein of beet yellows closterovirus is a homologue of HSP70 heat shock proteins

A portion of the RNA genome of beet yellows closterovirus (BYV) has been sequenced encompassing a complete long open reading frame (ORF) potentially encoding a 65 kDa protein. The sequence of this putative protein was strikingly similar to those of HSP70-related heat shock proteins. The counterparts of all the eight segments strongly conserved in HSP70s could be confidently identified in the BYV 65 kDa protein. It is suggested that some of these segments might be the ATP-binding site(s) and that, similarly to the heat shock proteins, the 65 kDa is probably ATP-binding. Generally, however, the divergence between the 65 kDa sequence and the sequences of the HSP70s was much more pronounced than that between any two members of the latter family, allowing a clearer delineation of clusters of conserved residues that might be crucial for protein function. It is suggested that these observations will be helpful in functional dissection of the proteins of the HSP70 family. Analysis of the sequence of a portion of the ORF found upstream from the 65 kDa ORF showed that the C-terminal domain of the encoded protein could be an RNA-dependent RNA polymerase closely related to those of tricornaviruses, a family of RNA plant viruses with three component genomes.

Nucleotide sequence of the 3'-terminal half of beet yellows closterovirus RNA genome: unique arrangement of eight virus genes

The sequence of 6746 nucleotides representing the 3'-proximal half of the beet yellows closterovirus (BYV) genome was determined. In the direction 5' to 3', the sequence was composed of eight open reading frames (ORFs) potentially encoding proteins of 6.4K (ORF2), 65K (ORF3), 64K (ORF4), 24K (ORF5), 22K (ORF6), 20K (ORF7) and 21K (ORF8). An incomplete ORF, ORF1, encoded the C-terminal part of a putative RNA-dependent RNA polymerase, most closely related to polymerases of tricornaviruses; the putative product of ORF3, 65K, was found to be a homologue of the hsp70 family of cell heat-shock proteins. ORF2 potentially encoded a small hydrophobic 6.4K protein, apparently homologous to small hydrophobic proteins of potex- and carlaviruses. ORF6 encoded the viral coat protein, as indicated by its deduced Mr and amino acid composition. The products of ORFs 4, 5, 7 and 8 showed no significant similarities with protein sequences in the database and there are therefore no justifiable speculations concerning their possible functions. BYV RNA contains a 3'-terminal non-coding region of 181 nucleotides, with two stem-loop structures potentially folded within the 86 nucleotide sequence at the extreme 3' end. Analysis of the primary and secondary structure of this region together with the absence of aminoacylation and adenylylation in vitro showed that the BYV genome is devoid of a tRNA-like structure at its 3' end.

[Newly developed stenocardia: fibrinolysis and hemostasis at rest and during physical exercise after myocardial infarction]

Postmyocardial infarction patients with angina of new onset showed increased blood levels of fibrinogens, soluble fibrin and fibrinogen-fibrin degradation products one month after the acute onset of MI, while their baseline fibrinolysis had been normal. A variety of fibrinolytic disorders were revealed in response to physical stress.

Anomalous electrophoretic behavior of the major potato virus X RNA translation product

The major potato virus X (PVS) RNA translation product migrates in Laemmli's electrophoresis system as a 210 kDa polypeptide ('p210'). If a Tris-phosphate-SDS buffer system is used instead of a Tris-glycine-SDS one, the mobility of p210 is higher than that of the largest TMV RNA translation product, the 183 kDa protein. It is suggested that anomalous electrophoretic behavior of the largest PVX polypeptide during SDS-electrophoresis is due to its primary structure, namely to the presence of hydrophilic domains.

[Insulin and C-peptide secretion after physical exertion in men with newly manifested stenocardia and chronic ischemic heart disease]

Variation in insulin and C peptide levels was examined in patients with angina of new onset and chronic coronary heart disease. Insulin secretion was increased in all coronary patients, as compared to the controls, and hormonal response to additional stress was abnormal in postmyocardial infarction patients. It is demonstrated that insulin secretion is already changed at early stages of coronary disease, and the pattern of change is presented.