Mosaic Group Research Articles

Mosaic structure of the emission region of pulsar PSR 0329+54

AbstractWe performed the multifrequency time aligned measurements and the component structure analysis of the integrated profile of PSR 0329+54 in frequency range from 0.1 to 10 GHz. The result is that a commonly adopted five-component structure of the integrated profile does not provide a good match to the observed profiles. Only a six-component structure fits observations well. This result calls into question the validity of the two conal and core zones emission model. We suggest that the emission region inside of the cone of the open magnetic field lines represents a mosaic bunch of the discrete outflows of relativistic charges along magnetic field lines, injected by mosaic group of localized sparks in the polar cap. Our suggestion is based on the Rutherman and Sutherland belief that the polar gap discharges through a group of localized sparks, spaced at distances nearly equal to the height of the polar gap.Mode changing may be produced by the change of an activity of some sparks pattern without rearranging the structure of the emission region.

Bone mineral density in middle-aged women with Turner's syndrome.

Bone mineral density (BMD), bone mineral content and body composition were determined in 47 middle-aged (mean age 47.9 +/- 1.1 years) women with Turner's syndrome. Bone mineral density was measured in the forearm, femoral neck and total body. The women investigated had a BMD lower than the normal mean. When expressed as Z scores (individual values compared to normal reference data matched for age, weight and sex), the median Z score of the total body was -1.23. When comparing women with the karyotype 45,X and mosaic women, the latter showed a higher BMD in all sites of measurement. Duration of hormonal replacement therapy (HRT) differed significantly between the mosaic and the 45,X women, with a longer duration in the mosaic group (20.7 +/- 2 vs 12.1 +/- 2.6 years; p < 0.01). The duration of HRT was found to be the more important factor to maintain bone mass, not the karyotype. Bone mineral density increased with years of HRT but not until after > 20 years of HRT could a significant difference be shown between the women with HRT < or = 20 years and those with HRT > 20 years. No correlation was found between BMD and body weight, body fat or percentage body fat. Whether the osteopenia found in women with Turner's syndrome is similar to that found postmenopausally or is a specific form related to the chromosome aberration remains to be investigated further. The present data support a relation to estrogen deficiency.

The effects of sex steroids, and the X chromosome, on female brain function: A study of the neuropsychology of adult turner syndrome

Sex steroids and the X chromosome can independently affect cognitive abilities. Because subjects with Turner syndrome (TS) have gonadal aplasia, and various alterations in X chromosome structure and number, they provide a model to study the effects of sex steroids and of the X chromosome on human brain function. We used neuropsychological tests to study the cognitive abilities of 18 TS adults and 19 age/sex matched healthy controls. Nine TS subjects were mosaic for the 45,X karyotype, and 9 were non-mosaic 45,X (full TS). The TS group as a whole, compared to controls, had (i) significantly lower scores in tests of language and visual-spatial function, attention and memory, and (ii) a significantly greater discrepancy between verbal and performance scores. Mosaic TS subjects were intermediate between full TS and controls in some tests of verbal ability, but did not differ significantly from controls in others. Visuospatial ability was significantly lower than controls in both mosaic and full TS. Within the mosaic TS group, there was a significant negative correlation between visuospatial ability and % lymphocytes having a 45,X karyotype. Memory test scores were reduced independently of “X chromosome dosage” in all TS subjects. We conclude that in humans, the X chromosome is involved in development of both cerebral hemispheres, but moreso of the association neocortices. Also, sex steroids may modulate this effect— particularly in hippocampus.

The dermatological spectrum of Turner syndrome

AbstractTurner syndrome, characterized by monosomy of X chromosome, has a peculiar phenotype, including short stature, sexual infantilism, cardiovascular, renal, skeletal and skin abnormalities (in particular melanocytic naevi and skin appendage abnormalities). Fifty‐four patients affected by Turner syndrome were investigated. The skin and adnexal changes of Turner syndrome patients were analysed and their frequency was correlated with two karyotype groups (45, X and mosaicism group). A wide spectrum of skin findings was observed in Turner syndrome; in particular melanocytic naevi and pterygium colli were the most frequent findings. Pterygium colli was more frequent in patients with X monosomy than in those with other karyotypes (P &lt; 0.05). The frequency of congenital/congenital‐naevus‐like naevi (CN/CNLN) and acquired melanocytic naevi (AN) (81.6%) was higher in Turner syndrome subjects, independently of their karyotype, than in the general Caucasian population. However, there was an unexpectedly high frequency of ichthyotic changes, café‐au‐lait spots and halo naevi. Hypertrichosis, nail changes and keloid formation were also seen. No significant correlation was found between these dermatological findings and the two karyotype groups considered.Although there are no reports on the occurrence of melanoma in Turner syndrome, given the high prevalence of both small congenital and acquired naevi, these patients should also be considered for melanoma prevention.

X-chromosome effects on female brain: a magnetic resonance imaging study of Turner's syndrome

Summary Many neuropsychiatric disorders differ between the sexes in incidence, symptoms, and age at onset. To investigate the effects of X-chromosome aneuploidy and of sex steroid deficiency during childhood on brain structure and function, we used neuropsychological tests and quantitative magnetic resonance imaging (MRI) to study the brains of eighteen women with Turner's syndrome (TS) and nineteen healthy control women of similar age. Nine TS subjects had mosaic 45,X karyotypes, and 9 had non-mosaic 45,X. The TS group had significantly lower scores than the controls for all the Wechsler adult intelligence scale tests, except verbal comprehension and reading level. The greatest difference was in visuospatial construction (mean 90 [SD 12] vs 118 [13], p < 0·0001). The TS subjects also had a greater discrepancy than controls between verbal and performance intelligence quotients (9 [8] vs -5 [9], p<0 001). We found that TS subjects had significantly smaller values than controls in MRI-measured volumes of hippocampus, caudate, lenticular, and thalamic nuclei, and parieto-occipital brain matter, on both sides. Women with mosaic TS had values between the full TS and control groups for cerebral hemisphere and lenticular and thalamic nuclei volume and for verbal ability. Within the mosaic TS group, visuospatial ability was significantly correlated with the percentage of lymphocytes that had the 45,X karyotype. Hippocampal volume and memory test scores were significantly lower in mosaic and non-mosaic 45,XTS subjects than in controls. We postulate that in human beings the X chromosome plays an important part in the development and ageing of grey matter in striatum, diencephalon, and cerebral hemispheres.

Particle purification and properties of cassava Ivorian bacilliform virus

SummaryA virus found in cassava from the north‐west of the Ivory Coast was transmitted by inoculation with sap extracts to herbaceous species in six plant families. Chenopodium quinoa was used as a propagation host and C. murale was used for local lesion assays. The virus particles are bacilliform, c. 18 nm in diameter, with predominant lengths of 42,49 and 76 nm and a structure apparently similar to that found in alfalfa mosaic virus. Purified preparations of virus particles had A260/A280 of 1.7 ±0.05, contained one protein of Mrc. 22 000, and yielded three species of RNA with Mr (× 10‐6) of c. 0.7, 0.8 and 1.2. Although the virus particles were poorly immunogenic, an antiserum was produced and the virus was detected by enzyme‐linked immunosorbent assay (DAS‐ELISA) in leaf extracts at concentrations down to c. 6 ng/ml. Four other field isolates were also detected, including a strain which caused only mild systemic symptoms in C. quinoa instead of necrosis. The naturally infected cassava source plants were also infected with African cassava mosaic virus (ACMV) but when the new virus was cultured in Nicotiana benthamiana, either separately or together with ACMV, its concentration was the same. The new virus did not react with antisera to several plant viruses with small bacilliform or quasi‐bacilliform particles, and alfalfa mosaic virus reacted only weakly and inconsistently with antiserum to the cassava virus. The new virus, for which the name cassava Ivorian bacilliform virus is proposed, is tentatively classified as the second member of the alfalfa mosaic virus group.

Cognitive Development of Unselected Girls with Complete and Partial X Monosomy

The cognitive development of nine girls with 45,X and 45,X variant karyotypes, seven 45,X mosaics, and nine 46,XX control subjects (ages 8 to 17 years) followed since birth was evaluated. The nonmosaic group was slightly delayed in walking, had a moderately decreased full-scale and performance IQ, demonstrated a striking deficit in perceptual organization and fine motor execution, but had generally average language skills. Three nonmosaic girls with low intelligence were identified and one subject had above average intelligence. Intelligence was not correlated with the presence of physical stigmata. No obvious developmental differences were found between the three girls with 45,X variant, two with partial Xq deletions and one with a ring X chromosome, and the six girls with 45,X genotype. The 45,X mosaic group did not experience early developmental delays and was not significantly different from control subjects on any IQ score. A large amount of variability between subjects was noted, which could be partially attributed to family characteristics and socioeconomic conditions. Whereas this study corroborates previous findings of specific intellectual deficits in 45,X populations, it emphasizes the need for caution in estimating the cognitive development of any X and partial X monosomic infant.

Cutaneous and mucosal warts. Clinical and histopathological criteria for classification.

The clinical and histopathological study of cutaneous and mucosal warts demonstrates divergences between clinical and histopathological diagnoses among the group of myrmecias, mosaics, acrodigitate, and common warts. There is correlations criteria (when considered separately), such as hyperkeratosis and absence of keratohyaline granules in flat warts, and in ano-genital vegetations. The existence of clinical and histological overlaps emphasizes that it is not clear whether these cases are rare clinical varieties caused by as yet unknown types of human papillomaviruses, or rather by differences in the degree of keratinization at different sites in the body.

Viroid-like RNA encapsidated in lucerne transient streak virus

Lucerne transient streak virus (LTSV) has been isolated from lucerne crops in Australia and New Zealand [ 121. The virus was characterised and shown to share many properties with members of the southern bean mosaic virus group [3]. Velvet tobacco mottle virus (VTMOV), solanum nodiflorum mottle virus (SNMV) and subterranean clover mottle virus (SCMoV) have properties similar to those of southern bean mosaic virus (SBMV), but have an unusual RNA complement [4,.5]. In addition to virus-like linear single-stranded (ss)-RNA molecules, viroid-like circular ss-RNA molecules were also present [4-61. Virusand viroid-like RNA molecules of VTMoV and SNMV have no base sequence homology and both are essential for infection [7,8]. Here we examine the RNA complement of highly purified preparations of LTSV and show it to consist of both virusand viroid-like RNA molecules. instrument, virus preparations were stained with 2% uranyl acetate and RNA preparations were spread under denaturing conditions and rotary shadowed [4]. Preparations of RNA 2 and RNA 3 were isolated by polyacrylamide gel electrophoresis under denaturing conditions followed by sucrose density-gradient centrifugation [7]. Thermal denaturation of the RNAs in 1 X SSC buffer (0.15 M NaCl t 0.015 M sodium citrate pH 7.0) was determined as in [7].

Correlation between particle multiplicity and location on virion RNA of the assembly initiation site for viruses of the tobacco mosaic virus group

The initiation site for reconstitution on genome RNA was determined by electron microscopic serology for a watermelon strain of cucumber green mottle mosaic virus (CGMMV-W), which is chemically and serologically related to tobacco mosaic virus (TMV). The initiation site was located at the same position as that of the cowpea strain, a virus that produces short rods of encapsidated subgenomic messenger RNA for the coat protein (a two-component TMV), being about 320 nucleotides away from the 3' terminus, and hence within the coat protein cistron. Although CGMMV-W was until now believed to be a single-component TMV, the location of the initiation site indicated the presence of short rods containing coat protein messenger RNA in CGMMV-W-infected tissue, as in the case for the cowpea strain. We found such short rods in CGMMV-W-infected tissue. The results confirmed our previous hypothesis that the site of the initiation region for reconstitution determines the rod multiplicity of TMV. The finding of the second two-component TMV, CGMMV, indicates that the cowpea strain of TMV is not unique in being a two-component virus and that the location of the assembly initiation site on the genome RNA can be a criterion for grouping of viruses.

Crystallization of cowpea chlorotic mottle virus.

Abstract Cowpea chlorotic mottle virus belongs to the brome mosaic virus group of the small spherical plant viruses. It contains 180 protein subunits, which are arranged on a T = 3 icosahedral surface lattice. The virus crystallizes in orthorhombic space group P 2 1 2 1 2 ( a = 394 A , b = 382 A , and c = 397 A ). The unit cell contains four virus particles, while the crystallographic asymmetric unit consists of one complete virion. X-ray diffraction data from the crystals extend to nearly 3.0 A resolution.

Crystallization of belladonna mottle virus

Abstract Belladonna mottle virus belongs to the turnip yellows mosaic virus group of the small spherical plant viruses. It contains 180 protein subunits, which are arranged in a T = 3 icosahedral surface lattice. The top and bottom viral components crystallize isomorphously in hexagonal space group R 3 ( a = b = 296 A , c = 729 A ). The unit cell contains three virus particles, while the crystallographic asymmetric unit consists of only one-third of a particle. X-ray diffraction data from the crystals extend to at least 3.8 A resolution.

Serological Studies on the Relationships of Some Isometric Viruses of Gramineae

SUMMARY Particles of 17 isolates of viruses from Gramineae were purified and the virus relationships assessed by different serological techniques. From the reaction end-points of antisera in agar gel double diffusion tests the serological differentiation indices of reciprocal tests were calculated. These indices were used to construct a scheme of serological interrelationship. Spur formation tests were used to distinguish between closely related, non-identical viruses. The isolates were shown to belong to four groups, one of which (the cocksfoot mild mosaicpanicum mosaic virus group) contains most of the isolates and can be subdivided into two main clusters (typified by cocksfoot mild mosaic and panicum mosaic viruses, respectively). Additional information was obtained by immunoelectrophoresis of the viruses with their homologous antisera and by the determination of the mol. wt. of the coat protein subunits using SDS-polyacrylamide gel electrophoresis. The data obtained by both methods agree with the above mentioned results, although some minor differences were found between the immunoelectrophoretic patterns of panicum mosaic virus and its relatives and also the three isolates of Cynosurus mottle virus. Reversed rocket electrophoresis did not provide any information of use in virus grouping. Brome mosaic virus did not react with the antisera to the 17 viruses, but tobacco mosaic virus reacted weakly with all the antisera and also with one of the antisera to brome mosaic virus. These and other recently published results are discussed.

The banding behaviour of the viruses of southern bean mosaic virus group in gradients of caesium sulphate

At pH 5.0 type and severe bean strains of southern bean mosaic virus (SBMV) form multiple bands in Cs 2SO 4 gradients. Two banding zones, heavy and light, were recognized; the SBMV type strain had 3–5 bands in the light zone and 1 or 2 bands in the heavy zone. SBMV cowpea and Ghana strains formed one band in each zone as did sowbane mosaic, rice yellow mottle, and turnip rosette viruses. Carnation mottle virus formed two bands in the light zone and cocksfoot mottle virus formed two bands in the heavy zone. Each of these viruses formed one band in CsCl gradients. The effects of pH, chelating agents, and divalent cations on the banding behaviour of these viruses in Cs 2SO 4 gradients was examined, and the possible causes of the heterogeneity are discussed.

The stabilization of the particles of turnip rosette virus and of other members of the southern bean mosaic virus group

The particles of turnip rosette virus and of other members of the southern bean mosaic virus (SBMV) group can be swollen and become salt labile by the addition of EDTA at alkaline pH values. By studying the effects of type and concentration of chelator, of pH and of salt concentration, it is concluded that the particles of these viruses are stabilized by three types of bond, one involving divalent cations, one being pH-dependent, and one a salt link between protein and RNA. Carnation mottle virus (not a member of the SBMV group) particles are stabilized by the first two bond types but not effectively by the protein-RNA link.

Comparison of Mental Development in Individuals With Mosaic and Trisomy 21 Down's Syndrome

During the past 15 years about 350 children with Down's syndrome have been seen at Children's Hospital of Los Angeles for psychological evaluation along with medical visits and other laboratory tests. Among this group there were 25 mosaic Down's syndrome children identified by chromosome analyses. They were matched for sex and chronological age with 25 trisomy 21 subjects and compared on psychological tests. The mosaic group demonstrated significantly higher intellectual potential, better verbal facility, and less visual perceptual difficulties than the trisomy 21 group. Their behavioral adjustment and personality characterisitcs were similar to those observed in other types of Down's syndrome. Since present psychological assessment techniques do not permit reaching valid conclusions about the ultimate intellectual status in very young infants with Down's syndrome, physicians and other professionals need to be careful when recommending early placement outside the home based merely upon the diagnosis.

Host range and some properties of Physalis mosaic virus, a new virus of the turnip yellow mosaic virus group

An apparently undescribed virus was isolated fromPhysalis subglabrata in Illinois, USA, and its properties were studied. The virus was namedPhysalis mosaic virus (PMV). It was readily transmitted by sap inoculation to 23 out of 34 Solanaceae tested, toChenopodium foetidum andSonchus oleraceus but not to 28 other non-solanaceous species inoculated. Purified preparations of PMV contained isometric particles of 27 nm in diameter, which sedimented as two components with sedimentation coefficients of 50 and 112 S. The 112 S component was infectious, the 52 S component was not. The virus contained 38% ribonucleic acid with a molar base content of G 14.4%, A 22.9%, C 37,2% and U 25.5%.

Serological interrelationships in the turnip yellow mosaic virus group

The serological interrelationships between eleven viruses in the turnip yellow mosaic virus group (tymoviruses) were studied with 286 antisera from 48 rabbits. Antisera from different rabbits and from different bleedings of the same rabbit showed considerable differences in their homologous and heterologous reactivities. A classification based on average serological differentiation indices is proposed. There is a continuous range of serological relationships in the tymovirus group and subdivision into a turnip yellow mosaic virus and an Andean potato latent virus subgroup does not seem justified.

Strawberry Vein-Banding Virus, a Member of the Cauliflower Mosaic Virus Group

SUMMARY Cytoplasmic inclusions, made up of a dense, finely granular matrix up to 3 to 4 µm in diam. were consistently found in ultrathin sections of leaf tissues from Fragaria vesca infected with strawberry vein-banding virus (SVBV). Isometric particles, usually with ring-like profiles, 40 to 45 nm in diam. were seen either embedded in the dense matrix or scattered in some electron-lucent areas of the inclusion. The particle morphology and the type of the inclusion found associated with SVBV places it in the cauliflower mosaic virus group.

Intracellular Location and some Properties of Mirabilis mosaic virus, a New Member of the Cauliflower mosaic Group of Viruses

Intracellular Location and some Properties of Mirabilis mosaic virus, a New Member of the Cauliflower mosaic Group of Viruses