Molecular and serological characterization of iris yellow spot virus, a new and distinct tospovirus species

ABSTRACT A new tospovirus was identified in iris cultivations in the Netherlands. Both serological comparisons and sequence determination of the S RNA demonstrate that this virus represents a new and distinct species, belonging to a separate serogroup, and for which the name iris yellow spot virus (IYSV) is proposed. The disease symptoms on iris are characterized by yellow spots on the leaves. Its experimental host range is very narrow and, in addition to iris, only includes Nicotiana benthamiana and Datura stramonium. The nucleoprotein of IYSV shows only 30 to 44% sequence identity with those of other tospoviruses identified so far; the highest homology being found with the tospovirus species of serogroup IV.

Molecular characterization of tomato spotted Wilt virus defective interfering RNAs and detection of truncated L proteins

Junction sites of 25 different defective interfering (DI) RNAs of tomato spotted wilt virus (TSWV) were characterized. The DI RNAs varied in size from 2.0 to 5.2 kilobases (kb) and contained a single internal deletion. The absence of DI RNAs smaller than 2 kb suggested a size constraint for the survival of TSWV DI RNAs. This hypothesis was reinforced by the finding of a dimeric DI RNA formed by two 1.6-long monomers linked head to tail. Three types of junction sites were found, one type originating from a simple deletion; the second type contained a few extra nucleotides of unknown origin; and the third type contained a stretch of three to five nucleotides, originally occurring at both sides of the deletion and of which one was deleted. In 19 of the 25 DI RNAs studied, the original reading frame was maintained, suggesting a selective preference of DI RNAs with translational potency. Truncated proteins encoded by these DI RNAs were indeed detected in the nucleocapsid preparations. Folding studies of the complete L RNA revealed that the calculated minimal energy of folding was at 16 degreesC lower than at 23 degrees, indicating a higher stability of this molecule at low temperatures. The results suggest an involvement of locally folded secondary structures in the process of deletion, rather than the requirement of certain sequences around the deletion point. The DI RNA generation in TSWV is essentially, as discussed, similar to the process of RNA recombination described in many viruses.

Characterization of petunia flower mottle virus (PetFMV), a new potyvirus infecting Petunia x hybrida

With the introduction of cutting-grown Petunia x hybrida plants on the European market, a new potyvirus which showed no serological reaction with antisera against any other potyviruses infecting petunias was discovered. Infected leaves contained flexuous rod-shaped virus particles of 750-800 nm in length and inclusion bodies (pinwheel structures) typical for potyviruses in ultrathin leaf sections. The purified coat protein with a Mr of approximately 36 kDa could be detected in Western immunoblots with a specific antibody to the coat protein of the petunia-infecting virus. The 3' end of the viral genome encompassing the 3' non-coding region, the coat protein gene, and part of the NIb gene was amplified from infected leaf material by IC/PCR using degenerate and specific primers. Sequences of PCR-generated cDNA clones were compared to other known sequences of potyviruses. Maximum homology of 56% was found in the 3' non-coding region between the petunia isolate and other potyviruses. A maximum homology of 69% was found between the amino acid sequence of the coat protein of the petunia isolate and corresponding sequences of other potyviruses. These data indicate that the petunia-infecting virus is a previously undescribed potyvirus and the name petunia flower mottle virus (PetFMV) is suggested.

Comparative cytophotometric analysis of reactive lymphoid hyperplasia and low malignant non-Hodgkin lymphoma

In fine needle aspiration biopsy (FNAB) of lymph nodes, differential diagnosis between reactive lymphoid hyperplasia (RLH) and low grade non-Hodgkin lymphoma (NHL) may be sometimes difficult. Cytophotometric analysis of DNA content using image analysis has found practical application in the determination of malignancy in different tumours. In this study, image cytometry was applied to compare the ploidy status of the above mentioned lesions to obtain diagnostically helpful information. Thirty smears of histologically proven low grade NHL (10 follicular lymphomas of centroblastic-centrocytic type, 10 lympho-plasmocytoid immunocytomas, 10 chronic lymphocytic leukemias) and 15 smears of RLH were stained with Feulgen and examined by image analysis (CAS 200, Becton Dickinson). The 5c exceeding rate was determined according to the Boecking's definition of aneuploidy. Concerning the histogram types the Auer classification was used. The aneuploidy was found in 4/10 follicular lymphomas and 4/10 lymphoplasmocytoid immunocytomas. All chronic lymphocytic leukemias were diploid. In none RLH a 5c exceeding rate was found. The results verify the value of image cytophotometry as a helpful method in some diagnostically difficult cases.

The sector-wide approach in health: what is it? Where is it leading?

This paper describes early experience with the Sector-Wide Approach (SWAp), an emerging trend in development practice in low-income countries. The paper describes what a SWAp is, and why it is now being pursued. The SWAp is characterized as a sustained government-led partnership with donor agencies and other groups. By applying sector-wide policies to an expenditure framework and national implementation systems, explicit health sector reforms are undertaken to meet sectoral and national development objectives. The approach has changed the dynamic between governments and donor agencies, requiring systemic changes in policy-making and management in both governments and donor agencies. With the SWAp, ongoing joint assessment and negotiations around sectoral plans and review of performance replaces the old way of preparing and supervising projects. Early experiences in countries undergoing SWAps are discussed, including the problem of reconciling priority programs and old practices with broader health sector reforms and new ways of managing development assistance. The paper concludes by identifying some of the key challenges for the future of SWAps.

Binding of Tomato Spotted Wilt Virus to a 94-kDa Thrips Protein

ABSTRACT Using protein blot assays, a 94-kDa thrips protein was identified that exhibited specific binding to tomato spotted wilt virus (TSWV) particles. Renaturation of the 94-kDa protein, which is conserved among the two major vector species of TSWV, Frankliniella occidentalis and Thrips tabaci, was crucial for its virus-binding properties, whereas under the same conditions no specific binding was observed with aphid (Myzus persicae) proteins. The 94-kDa protein species was present in all developmental stages of both vectoring thrips, whereas it was present mainly in the adult stage of a nonvectoring thrips species, Parthenothrips dracenae. Using antibodies against the different TSWV structural proteins, the G2 envelope glycoprotein was identified as the viral determinant involved. Because the virus-binding protein is present throughout the thrips body, but not in the gut, it may represent a receptor protein involved during circulation of the virus through its vector but probably not during viral uptake in the midgut.

A natural classification of alcoholics by means of statistical grouping methods

AIMS

The results of previous studies using statistical grouping methods for subtyping of alcoholics did not converge to a coherent natural classification, probably among other things as a consequence of improper selection of methods. As an alternative an analytic strategy is formulated and tested. First, a cluster procedure tests a categorical model of the data. If no compact isolated groups are detected non-metric multi-dimensional scaling is used to unravel the complex relations in the data by reconstructing a low dimensional spatial solution.

DESIGN

Cross-sectional study.

SETTING

In and outpatient treatment programs of the Amsterdam health region in The Netherlands.

PARTICIPANTS

A consecutive sample of 277 men and women voluntarily seeking treatment for their alcohol problems. No exclusion criteria were applied.

MEASUREMENTS

A sample of 102 symptoms reflecting various aspects of alcoholism measured by structured self-report questionnaire (93 symptoms) or derived from a semi-structured interview taken by treatment staff (nine symptoms).

FINDINGS

The cluster procedure failed to show a fitting categorical model. Non-metric multi-dimensional scaling produced a three-dimensional spatial solution. The first dimension reflects the alcohol dependence syndrome. The second bipolar dimension reveals a male-dominated anti-social alcoholism, and a female-dominated pattern of isolated home drinking. The third bipolar dimension represents chronic alcoholism, and young quarrelsome people from troubled families.

CONCLUSIONS

The three-dimensional solution obtained has a high face validity and incorporates a number of aspects of previous classifications. The results illustrate the strength of the analytic strategy in unravelling complex symptomatology. Limitations of the classification obtained are stressed and directions for subsequent validation research are given.

Population predictors of community health and social service use in Northern Ireland

STUDY OBJECTIVE

To investigate the characteristics of elderly populations associated with variations in their use of community health and personal social services and to test the hypotheses that the variations are related to: (a) the age structure of an elderly population; (b) the population's socioeconomic composition, including the level of deprivation; and (c) household or living arrangements.

DESIGN

A common file of 1991 population census and 1994 NHS community trust operational variables was constructed for 67 postcode sectors, with the independent variables describing the age-sex groups to be studied. Clear criteria for the exclusion of "empty" sectors were developed. Relationships using bivariate and multivariate correlation and stepwise multiple regression were explored.

SETTING

Eastern Health and Social Services Board area, Northern Ireland (Belfast and hinterland).

PARTICIPANTS

Population of statutory pensionable age; in aggregate, younger and older age bands.

MAIN RESULTS

The age structure or mean age of the elderly population had only a weak association with the community health and social service client rate, but there were strong associations with socio-economic variables, particularly the percentage of those living alone who were without a car and the percentage of pensioner households that included an adult of below pensionable age. Parsimonious multiple regression models accounted for between 46% and 80% of the variation in the NHS community trust client rate. Greater explanations were achieved for the young elderly population than for those aged 75+ years and, when the population was divided between young and old age bands, for men than for women.

CONCLUSIONS

Community health and social services for elderly people in eastern Northern Ireland were focused on those with a low income and those who were not co-resident with adults of working age. When local elderly populations are compared, per capita morbidity and dependency are often higher where the mean age is low, and vice versa, because of the inverse relationship between socioeconomic status and survival in old age. Capitation scales for resource allocation with positive age weighting will be of little use if no account is taken of the relative prevalence of need in the youngest or base age group.

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis

BACKGROUND

We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate.

METHODS

After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 micrograms/application), heparin (250 micrograms/application) or suramin (250 micrograms/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n = 48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed.

RESULTS

Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs.

CONCLUSIONS

These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.

Effects of Temperature and Host on the Generation of Tomato Spotted Wilt Virus Defective Interfering RNAs

ABSTRACT The generation of defective interfering (DI) RNA molecules of tomato spotted wilt tospovirus (TSWV) was studied by serially passaging in-ocula from plant to plant under different controlled conditions. DI RNAs were generated at higher rates in plants at 16 degrees C than in plants incubated at higher temperatures. Another factor promoting the TSWV DI RNA generation was the use of high virus concentrations in the inocula. The solanaceous species Capsicum annuum, Datura stramonium, Lycopersicon esculentum, Nicotiana benthamiana, and N. rustica supported the generation of DI RNAs, whereas the virus recovered from the inoculated composite species, Emilia sonchifolia, remained free of any DI RNA under all conditions tested. This study resulted in a strategy to maintain DI RNA-free TSWV isolates, as well as in an efficient way to produce a large population of different DI RNA species. A single DI RNA species usually became dominant in an isolate after a few rounds of serial inoculations. The possible mechanisms involved in TSWV DI RNA generation under different inoculation circumstances are discussed.

Multiplication of tomato spotted wilt virus in primary cell cultures derived from two thrips species

Primary cell cultures prepared from embryos of the thrips species Frankliniella occidentalis and Thrips tabaci were tested for their potential to support replication of tomato spotted wilt virus (TSWV). Using polyclonal antibodies against the viral nucleocapsid protein (N) and indirect immunofluorescent staining, discrete spots with strong signals were observed in the cytoplasm at 48 h post-inoculation in the cell cultures of a F. occidentalis, and a T. tabaci population which failed to transmit the virus. The infection was found in approximately 40% of the monolayer cells. Using antibodies against a nonstructural protein (NSs) of TSWV, uniform and more diffused staining was observed throughout the cytoplasm of these cells, underlying active genome replication. The NSs protein accumulated slower than the N protein in the cells of both thrips species. No multiplication of TSWV was observed in a heterologous insect cell line, i.e. from Spodoptera frugiperda, suggesting the existence of specific host factors in the thrips-derived cells.

Enhanced cyclooxygenase-2 gene expression in alcoholic liver disease in the rat

BACKGROUND & AIMS

Inflammatory stimuli and lipid peroxidation up-regulate cyclooxygenase (COX)-2. This study evaluated the relationship between inflammatory mediators, COX expression, and pathological changes in experimental alcoholic liver disease.

METHODS

Rats (5 per group) were fed ethanol and a diet containing saturated fat, corn oil, or fish oil by intragastric infusion. Dextrose isocalorically replaced ethanol in controls. In the first set of experiments, whole livers were analyzed. In the second set of experiments, Kupffer cells, endothelial cells, and hepatocytes were isolated from rats in each group. Pathological analyses and measurements of lipid peroxidation, tumor necrosis factor (TNF)-alpha, COX-1 and COX-2 messenger RNA (mRNA), endotoxin, and liver and plasma thromboxane were performed.

RESULTS

Increased expression of COX-2 mRNA was detected in the livers of rats showing necroinflammatory changes. The Kupffer cell was the cell primarily responsible for the increase in COX-2 mRNA level. Increased expression of COX-2 was associated with increased levels of endotoxin, TNF-alpha mRNA, lipid peroxidation, and synthesis of thromboxane. COX-1 mRNA was decreased in Kupffer cells in rats with the most severe liver injury.

CONCLUSIONS

Up-regulation of COX-2 in alcoholic liver injury occurred in the presence of proinflammatory stimuli and resulted in increased synthesis of inflammatory and vasoactive eicosanoids. Down-regulation of COX-1 may result in decreased synthesis of cytoprotective eicosanoids and additionally exacerbate liver injury.

Serological comparison of tospoviruses with polyclonal antibodies produced against the main structural proteins of tomato spotted wilt virus

A new purification procedure for the tospoviruses of serogroups II and III was developed. SDS-polyacrylamide gel electrophoresis of purified tomato spotted wilt virus (TSWV; serogroup I), groundnut ringspot virus (GRSV: serogroup II), tomato chlorotic spot virus (TCSV; serogroup II) and impatiens necrotic spot virus (INSV; serogroup III) showed that the glycoprotein G2 of serogroup II members differs significantly in size from that of the serogroup I virus. Western immunoblot analysis using polyclonal antisera produced against purified glycoproteins TSWV-G1 and G2 as well as peptides of hydrophilic sequences of TSWV-G1 and G2 expressed in Escherichia coli demonstrated a higher homology amongst G1 of different serogroups than for G2. These results are supported by comparing the glycoprotein gene sequences of different serogroups.

Isolated polycystic liver disease as a distinct genetic disease, unlinked to polycystic kidney disease 1 and polycystic kidney disease 2

Polycystic liver disease (PLD) is proven to occur either sporadically or in association with autosomal dominant polycystic kidney disease (ADPKD), whereas the existence of an isolated (i.e., without any kidney cyst) familial form is disputed. We describe a family with definitely isolated PLD transmitted through three generations and exclude the linkage of the disease to the genetic markers of PKD1 and PKD2, the two main loci responsible for ADPKD. These findings strongly support the existence of PLD as a genetic disease distinct from the known forms of ADPKD.

Isolated polycystic liver disease as a distinct genetic disease, unlinked to polycystic kidney disease 1 and polycystic kidney disease 2

Polycystic liver disease (PLD) is proven to occur either sporadically or in association with autosomal dominant polycystic kidney disease (ADPKD), whereas the existence of an isolated (i.e., without any kidney cyst) familial form is disputed. We describe a family with definitely isolated PLD transmitted through three generations and exclude the linkage of the disease to the genetic markers of PKD1 and PKD2, the two main loci responsible for ADPKD. These findings strongly support the existence of PLD as a genetic disease distinct from the known forms of ADPKD.