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PubMed1976

Increased production of genetic mosaics in Habrobracon juglandis by cold shock of newly oviposited eggs.

Eggs from an ebony stock exposed to 5-5 degrees C prior to syngamy exhibited increased production of genetic mosaics in comparison with untreated eggs from the same females. No increase in mosaic production occurred for cold-shocked cleavage-stage embryos from the ebony stock or from pre-cleavage cold-shocked eggs from a wild-type stock. Heat shock of pre-syngamy eggs also failed to increase the production of genetic mosaics. These findings are consistent with predictions based on the post-cleavage fertilization theory of mosaic origin in Habrobracon or with a hypothesis of differential mortality.

Animals↗
PubMed2000

Third Prader-Willi syndrome phenotype due to maternal uniparental disomy 15 with mosaic trisomy 15.

We report on a boy with mosaicism for trisomy 15 and Prader-Willi syndrome (PWS) due to maternal isodisomy for chromosome 15. His phenotype is consistent with PWS and trisomy 15 mosaicism. Although our patient is unusual in having maternal isodisomy rather than the more common maternal heterodisomy, we think that his more severe PWS phenotype is due to his trisomy 15 mosaicism rather than to homozygosity for deleterious chromosome 15 genes. We propose that individuals with PWS have one of three similar but distinctive phenotypes depending on the cause of their condition. Patients with paternal deletions have the typical PWS phenotype, patients with maternal UPD have a slightly milder phenotype with better cognitive function, and those with maternal UPD and mosaic trisomy 15 have the most severe phenotype with a high incidence of congenital heart disease. These phenotype-genotype differences are useful to guide the work-up of patients with suspected PWS and to provide prognostic counseling for families.

Chromosome Aberrations↗
PubMed2002

Horizontal cell density and mosaic regularity in pigmented and albino mouse retina.

The present study has examined the density and mosaic regularity of the population of horizontal cells in the pigmented and albino mouse retina. Retinal wholemounts were immunostained for calbindin, and labeled cells within sampled fields were analyzed to determine horizontal cell soma size and density. The X-Y positional coordinates of each cell were determined, from which the geometrical properties of the mosaic were examined using nearest neighbor and Voronoi domain analyses, and regularity indices were derived from those measures. Autocorrelation and density recovery profile analyses were also conducted to identify the presence of exclusion zones within the population of horizontal cells. For each sampled field, random simulations of matched density, constrained by the physical size of the horizontal cells, were generated and analyzed in parallel. Neither retinal area, nor horizontal cell soma size, nor density differed between the pigmented and albino retinas. Mosaic regularity in pigmented and albino retinas did not differ, but each differed significantly from random simulations of identical density. Horizontal cells in the mouse retina exhibit exclusion zones extending beyond the physical size of the soma, but these were identical in size in the pigmented and albino retina. Such exclusion zones are suggested to reflect homotypic interactions between horizontal cells during early development that mediate cellular repulsion and tangential movement. The lack of any discernable effect brought about by the albino mutation, despite numerous developmental abnormalities associated with the retinal neuroepithelium in albino mice, is consistent with other results showing that homotypic interactions are sufficient for the genesis of the global patterning characteristic of mature retinal mosaics.

Albinism↗
PubMed1997

Mosaic pattern of gliosis in the neostriatum of a North American man with craniocervical dystonia and parkinsonism.

We present the case of a 51-year-old patient with a 31-year history of psychiatric symptoms, craniocervical dystonia, bulbar dysfunction, and parkinsonism. His dystonic movements included blepharospasm, jaw opening and lingual dystonia, and spasmodic retrocollis. Psychiatric symptoms included psychosis and depression, with onset years before the movement disorder. After his death by aspiration, examination of his brain revealed abnormalities limited to the neostriatum. Staining of brain sections, including Holzer, glial fibrillary acidic protein, and immunohistochemical stain for calbindin D28k, revealed the presence of a mosaic pattern of gliosis with neuronal loss (sparing large neurons) within this region. The islands of tissue between stands of gliosis had a normal appearance. This patient represents only the fourth case (and first North American born) with a mosaic pattern of gliosis in the neostriatum. The clinical and pathologic features were similar in all four cases except that our patient was the first with prominent psychiatric symptoms and a more stable, less progressive course. Mosaicism has been described in the X-linked Filipino disorder Lubag. Occurrence in non-Filipino patients, such as ours, suggest that either Lubag can develop in non-Filipino families or that mosaicism is a nonspecific pathologic finding in some patients with idiopathic dystonia. Finally, our case reports the notion that craniocervical dystonia may result from neostriatal dysfunction.

Age of Onset↗
PubMed2004

Prenatal diagnosis of mosaic trisomy 16 associated with congenital diaphragmatic hernia and elevated maternal serum alpha-fetoprotein and human chorionic gonadotrophin.

OBJECTIVES: To present the clinical, cytogenetic, and molecular findings of prenatally diagnosed mosaic trisomy 16. CASE: A 30-year-old gravida 2, para 1 woman was referred for amniocentesis because of a positive maternal serum screen result with elevated maternal serum alpha-fetoprotein (MSAFP) and maternal serum free beta-human chorionic gonadotrophin (MSfreebeta-hCG). Cytogenetic analysis of amniotic fluid at 21 weeks' gestation revealed mosaicism for trisomy 16, 47,XX,+16[3]/46,XX[15]. Ultrasonography demonstrated right diaphragmatic hernia and agenesis of left umbilical artery. The pregnancy was terminated subsequently. The karyotype of the cord blood was 46,XX. Cytogenetic analyses of the multiple sampled tissue specimens showed a karyotype of 47,XX,+16 in the placenta and 47,XX,+16/46,XX with various levels of trisomy 16 in the umbilical cord and skin. Molecular studies showed that the trisomy 16 in the placenta was likely to have resulted from a maternal meiosis II nondisjunction error. Partial dosage increase of an extra maternal allele was noted in the skin and umbilical cord. CONCLUSION: Fetuses with mosaic trisomy 16 may be associated with congenital diaphragmatic hernia and elevated MSAFP and MShCG. Fetal blood sampling is of a limited value in confirming mosaic trisomy 16 ascertained through amniocentesis.

Abortion, Induced↗
PubMed2000

Genomic sequences of bacteriophages HK97 and HK022: pervasive genetic mosaicism in the lambdoid bacteriophages.

We report the complete genome DNA sequences of HK97 (39,732 bp) and HK022 (40,751 bp), double-stranded DNA bacteriophages of Escherichia coli and members of the lambdoid or lambda-like group of phages. We provide a comparative analysis of these sequences with each other and with two previously determined lambdoid family genome sequences, those of E. coli phage lambda and Salmonella typhimurium phage P22. The comparisons confirm that these phages are genetic mosaics, with mosaic segments separated by sharp transitions in the sequence. The mosaicism provides clear evidence that horizontal exchange of genetic material is a major component of evolution for these viruses. The data suggest a model for evolution in which diversity is generated by a combination of illegitimate and homologous recombination and mutational drift, and selection for function produces a population in which most of the surviving mosaic boundaries are located at gene boundaries or, in some cases, at protein domain boundaries within genes. Comparisons of these genomes highlight a number of differences that allow plausible inferences of specific evolutionary scenarios for some parts of the genome. The comparative analysis also allows some inferences about function of genes or other genetic elements. We give examples for the generalized recombination genes of HK97, HK022 and P22, and for a putative headtail adaptor protein of HK97 and HK022. We also use the comparative approach to identify a new class of genetic elements, the morons, which consist of a protein-coding region flanked by a putative delta 70 promoter and a putative factor-independent transcription terminator, all located between two genes that may be adjacent in a different phage. We argue that morons are autonomous genetic modules that are expressed from the repressed prophage. Sequence composition of the morons implies that they have entered the phages' genomes by horizontal transfer in relatively recent evolutionary time.

Amino Acid Sequence↗
PubMed1999

Formation of cone mosaic of zebrafish retina.

In the zebrafish retina, four types of cone photoreceptor cells (or cones) with different sensitive frequencies are arranged in a regular pattern, named "cone mosaic". A pair of small cones, one sensitive to red and the other sensitive to green, is in close contact and forms a "double cone". In addition, there are two kinds of single cones, sensitive to blue and to UV, respectively. We study characteristics of cell-differentiation rules that realize stable formation of cone mosaic. Assumptions are: undifferentiated cells are arranged in a regular square lattice, and they are one of the three types (B, U, and D cells). A D cell has two parts (G and R-parts) and takes one of the four directions. The cells change their cell type and orientation following a continuous-time Markovian chain. The state transtion occurs faster if it increases the stabilities of the focal cell, in which the stability is the sum of affinities with neighboring cells. After the transient period, the system may reach a stable pattern (pre-pattern). The pattern becomes fixed later when the cells are fully differentiated in which B cells, U cells, and D cells become blue-sensitive, UV-sensitive, and double cones, respectively. We search for the combinations of affinities between cell states that can generate the same cone mosaic patterns as in zerbrafish retina. Successful transition rules give (1) zero or small affinity with the pairs of cell states that are absent in the zebrafish cone mosaic (lambda(UR), lambda(BG)and the contact of two cells of the same type); (2) a large affinity between a part of D cells and a non-D cell (lambda(UG)and lambda(BR)); and (3) a positive affinity of an intermediate magnitude between two non-D cells (lambda(BU)) and between two parts of D cells (lambda(GR)). The latter should be of a magnitude of about 60-90% of the former. The time needed to form a regular pattern increases with the lattice size if all the cells start pre-pattern formation simultaneously. However, the convergence time is shortened considerably if the pre-pattern formation occurs only in a narrow band of morphogenetic cell layer that sweeps from one end of the lattice to the other.

Animals↗
PubMed1993

Characterisation and epitope analysis of monoclonal antibodies to virions of clover yellow vein and Johnsongrass mosaic potyviruses.

Mouse monoclonal antibodies (MAbs) against the Australian B strain of clover yellow vein (ClYVV-B) and the JG strain of Johnsongrass mosaic (JGMV) potyviruses were produced, characterised and the epitopes with which they reacted were deduced. Using intact particles of ClYVV a total of ten MAbs were obtained which reacted strongly with ClYVV-B in an enzyme-linked immunosorbent assay and Western blots. Four of these MAbs (1, 2, 4, and 13) were found to be ClYVV-specific, as they reacted with all five ClYVV strains from Australia and the U.S.A. but not with 11 strains of bean yellow mosaic (BYMV), pea mosaic (PMV), and white lupin mosaic (WLMV) viruses which, together with ClYVV, form the BYMV subgroup of potyvirses. These MAbs failed to react with eight other potyvirus species, including six which infect legumes like the viruses in the BYMV subgroup. The ClYVV MAb 10 was found to be BYMV subgroup-specific. It reacted strongly with 15 of the 16 strains of viruses in the subgroup and gave no reaction with eight other potyviruses. The other five ClYVV MAbs reacted with varying degrees of specificity with the BYMV subgroup viruses and also with other potyviruses. Eight of the ClYVV MAbs (1, 2, 4, 5, 13, 17, 21, and 22) reacted with the intact coat proteins only and not with the truncated (minus amino terminus) coat protein of ClYVV suggesting that the epitopes for these MAbs are located in the surface-exposed, amino-terminal region of the ClYVV coat protein. Comparison of published coat protein sequences of BYMV and ClYVV isolates indicated that the epitopes for the four ClYVV-specific MAbs may be in the amino-terminal region spanning amino acid residues 18 to 30, whereas those for the other four MAbs may be located in the first 17 amino-terminal amino acid residue region. The epitopes that reacted with BYMV subgroup-specific MAb 10 and MAb 30 which reacted with 20 of the 24 potyvirus isolates, are probably located in the core region of ClYVV coat protein as these MAbs reacted with the intact as well as truncated coat protein of ClYVV. Analysis, in Western blot immunoassay, of 17 MAbs raised against virions of JGMV revealed that only two MAbs (1-25 and 4-30) were JGMV-specific, whereas others displayed varying degrees of specificity to different potyviruses.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1982

Mutagen treatment of single Chinese hamster ovary cells produces colonies mosaic for glucose-6-phosphate dehydrogenase activity.

When populations of single Chinesee hamster ovary (CHO) cells were exposed to the mutagen ethyl methane sulfonate (EMS), allowed to grow into colonies, and stained for glucose-6-phosphate dehydrogenase (G6PD) activity, two types of unstained colonies were observed at a frequency of about on per thousand stained colonies. These negative-staining colonies consisted of (1) colonies uniformly deficient in staining activity (pure); and (2) colonies containing both stained and unstained sectors (mosaic) in various relative sizes and patterns. Unstained cells isolated from mosaic colonies were genetically stable and had significantly reduced or absent G6PD activity. Random cell aggregation or chromosome segregation from tetraploid cells is not a significant cause of the sectoring phenomenon. Also, mosaic colonies are not principally caused by mutation at one of two replicated G6PD genes and their subsequent segregation during division. The simplest explanation for this phenomenon is that EMS induces a mutational change in one of the two DNA strands and DNA replication then produces normal and mutant double-stranded DNAs which segregate into wild-type and G6PD-deficient cell types, producing a mosaic colony.

Animals↗
PubMed2004

Infectivity analysis of two variable DNA B components of Mungbean yellow mosaic virus-Vigna in Vigna mungo and Vigna radiata.

Mungbean yellow mosaic virus-Vigna (MYMV-Vig), a Begomovirus that causes yellow mosaic disease, was cloned from field-infected blackgram (Vigna mungo). One DNA A clone (KA30) and five different DNA B clones (KA21, KA22, KA27, KA28 and KA34) were obtained. The sequence identity in the 150-nt common region (CR) between DNA A and DNA B was highest (95%) for KA22 DNA B and lowest (85.6%) for KA27 DNA B. The Rep-binding domain had three complete 11-nt (5'-TGTATCGGTGT-3') iterons in KA22 DNA B (and KA21, KA28 and KA34), while the first iteron in KA27 DNA B (5'-ATCGGTGT-3') had a 3-nt deletion. KA27 DNA B, which exhibited 93.9% CR sequence identity to the mungbean-infecting MYMV, also shared the 3-nt deletion in the first iteron besides having an 18-nt insertion between the third iteron and the conserved nonanucleotide. MYMV was found to be closely related to KA27 DNA B in amino acid sequence identity of BV1 (94.1%) and BC1 (97.6%) proteins and in the organization of nuclear localization signal (NLS), nuclear export signal (NES) and phosphorylation sites. Agroinoculation of blackgram (V. mungo) and mungbean (V. radiata) with partial dimers of KA27 and KA22 DNA Bs along with DNA A caused distinctly different symptoms. KA22 DNA B caused more intense yellow mosaic symptoms with high viral DNA titre in blackgram. In contrast, KA27 DNA B caused more intense yellow mosaic symptoms with high viral DNA titre in mungbean. Thus, DNA B of MYMVVig is an important determinant of host-range between V. mungo and V. radiata.

Amino Acid Motifs↗
PubMed2005

Mapping a resistance gene in wheat cultivar Yangfu 9311 to yellow mosaic virus, using microsatellite markers.

Wheat yellow mosaic disease, which is caused by wheat yellow mosaic bymovirus (WYMV) and transmitted by soil-borne fungus, results in severe damage on wheat (Triticum aestivum L.) production in China. For development of resistant cultivars to reduce wheat yield losses due to wheat yellow mosaic disease, resistance test and genetic analysis indicated that a single dominant gene in wheat cultivar Yangfu 9311 contributed to the resistance. Bulk segregant analysis was used to identify microsatellite markers linked to the resistance gene in an F(2) population derived from the cross Yangfu 9311 (resistant) x Yangmai 10 (susceptible). Microsatellite markers Xwmc41, Xwmc181, Xpsp3039, and Xgwm349 were co-dominantly or dominantly linked with the gene responsible for WYMV resistance at a distance of 8.1-11.6 cM. Based on the wheat microsatellite consensus map and the results from amplification of the cultivar Chinese Spring nulli-tetrasomic stocks, the resistance gene to wheat yellow mosaic disease derived from Yangfu 9311, temporarily named as YmYF, was thus mapped on the long arm of chromosome 2D (2DL).

China↗
PubMed2005

Genetic mosaics in the massive persisting rhizosphere colony "shiro" of the ectomycorrhizal basidiomycete Tricholoma matsutake.

The ectomycorrhizal basidiomycete Tricholoma matsutake produces commercially valuable fruit bodies "matsutake" on a massive persisting rhizosphere aggregate of mycelia and mycorrhizas called "shiro." Using inter-retrotransposon amplified polymorphism analysis, we attempted to explore the potential diversity within the population of T. matsutake isolated from small Pinus densiflora woodlands located in various parts of Japan. In general, random phylogenetic relationship was noted among T. matsutake tested. The population from each limited sampling area was highly heterogeneous. Even some isolates from fruit bodies produced in the same shiro and those from spores in the same fruit bodies were found to be genetically diverse, indicating the occurrence of genetic mosaics in shiro. In a mosaic shiro, heterologous genets produced their fruit bodies concurrently. Data suggested that the dispersal of spores through sexual reproduction may have been more prevalent than generally accepted in T. matsutake to bring mosaicism and coordination of heterologous genets within the shiro. Implementation of management taking such diversity into consideration is urgently needed for the restoration of devastated matsutake fields in Japan. Exploration of individual clones in mosaic fungal resources that promote colonization and fruit body production is necessary for it.

Basidiomycota↗
PubMed2002

Complete nucleotide sequence of the genomic RNA of a French isolate of Pepino mosaic virus (PepMV). Brief report.

The complete nucleotide sequence of the genomic RNA of a French isolate of Pepino mosaic virus (PepMV) was determined. With a length of 6,425 nucleotides excluding the poly(A) tail at the 3' terminus, the PepMV genome contains five major open reading frames encoding a 164 kDa replicase, triple gene block proteins of 26 kDa, 14 kDa and 9 kDa, and a 25 kDa coat protein. This genome organization, as well as characteristic consensus motifs and high degrees of similarity of PepMV proteins with those of other potexviruses confirmed that PepMV belongs to the Potexvirus genus. Phylogenetic analyses carried out on replicase, triple gene block protein 1 and coat protein amino acid sequences revealed that PepMV is closely related to species Narcissus mosaic virus (NMV), Scallion virus X (SVX), Cymbidium mosaic virus (CymMV), and Potato aucuba mosaic virus (PAMV).

5' Untranslated Regions↗
PubMed2003

Molecular analysis of the 3' terminal region of the genome of Beet mosaic virus and its relation with other potyviruses.

A1633 nucleotides long 3'-terminal sequence of genome of the Beet mosaic virus (BtMV) Ren1 isolate from Slovakia, spanning a part of the NIb gene, complete capsid protein (CP) gene and a 3'non-coding region was determined. Computer-assisted translation resulted in a polypeptide encompassing typical conserved potyviral amino acid (aa) motifs. Homology BLAST search and phylogenetic analysis revealed that BtMV was closest to Bean common mosaic virus, Soybean mosaic virus and Zucchini yellow mosaic virus. An unexpectedly high, 99.6% aa sequence identity was found between BtMV-Ren1 and a previously sequenced British BtMV isolate. Restriction analysis and sequencing of the CP gene of other Slovak BtMV isolates revealed their high homology. Developed reverse transcription-polymerase chain reaction protocols enabled sensitive, rapid and reliable detection of the virus.

3' Untranslated Regions↗
PubMed2003

A virus related to soybean mosaic virus from Pinellia ternata in China and its comparison with local soybean SMV isolates.

A potyvirus isolated from Pinellia ternata in China was characterised and shown to be related to Soybean mosaic virus (SMV). The virus was pathogenic on P. ternata and some soybean cultivars, whereas the local soybean SMV isolate HH5 did not infect P. ternata. Western blot experiments demonstrated a serological relationship between the virus from Pinellia, SMV and Watermelon mosaic virus (WMV). The complete nucleotide sequences of the Pinellia virus (isolate P-1, 9735 nt) and of the Chinese soybean SMV isolates HH5 (9585 nt) and HZ (9588 nt) were determined. A 1733 nt sequence at the 3'-terminus of a second isolate from Pinellia (isolate P-2) was also determined. The predicted polyprotein of isolate P-1 has 83% amino acid (aa) identity with those of published SMV sequences. In many parts of the genome, aa identity was about 90% but it was much lower in the P1 protein region (24-29%), where it more closely resembled Dasheen mosaic virus (62%). The partial sequence of isolate P-2 had 91% nt identity to P-1 and both isolates resembled a recent sequence in the public databases (AF469171) wrongly named Zantedeschia mosaic virus. The two complete SMV soybean sequences had 93-95% nt identity with those of the previously sequenced isolates and >97% amino acid identity. Phylogenetic analysis and comparisons of coat proteins suggest that the Pinellia, WMV and SMV potyviruses should probably be treated as strains of the same species.

Amino Acid Sequence↗
PubMed2004

East African cassava mosaic Zanzibar virus - a recombinant begomovirus species with a mild phenotype.

Cassava plants exhibiting mild symptoms of cassava mosaic disease (CMD) were collected from Unguja island, Zanzibar. Cuttings grown from these plants in the glasshouse produced similar symptoms, which were milder than those caused by other known cassava mosaic geminiviruses (CMGs). The whitefly vector, Bemisia tabaci (Gennadius), transmitted the putative virus to 27.7% (n = 18) of target plants. Total DNA extracted from diseased leaves did not yield diagnostic PCR-bands using virus-specific primers to known CMGs. Degenerate primers, however, produced a diagnostic band indicating the presence of a begomovirus. Full-length DNA-A (2785 nucleotides) and DNA-B (2763 nucleotides) components were subsequently PCR-amplified, cloned and sequenced. Phylogenetic analyses of DNA-A and -B sequences showed that they were most similar to strains of East African cassava mosaic virus from Tanzania and Uganda at 83% and 86% nucleotide identities, respectively. The number and arrangement of open reading frames were similar to those of bipartite begomoviruses from the Old World. DNA-A was predicted to have recombined in the intergenic region (IR), AC1 and AC4 genes, and DNA-B in the IR. A maximum nucleotide identity of 83% in the DNA-A component with other sequenced begomoviruses, together with different biological properties allows this virus to be recognised as belonging to a new species named East African cassava mosaic Zanzibar virus (EACMZV).

Animals↗
PubMed2005

Biolistic infection of cassava using cloned components of Indian cassava mosaic virus.

Cassava mosaic disease (CMD) is a major constraint to cassava production in Africa and Asia. Of the two begomoviruses associated with CMD on the Indian subcontinent, Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus, only the latter has been successfully reintroduced into cassava to resolve the aetiology of the disease. Here, we report the complete nucleotide sequence of an ICMV isolate from Maharashtra (ICMV-[Mah2]), central India. Biolistic inoculation of the cloned components produced a systemic infection and typical mosaic symptoms in cassava, thereby fulfilling Koch's postulates. The availability of infectious clones will provide a valuable tool to screen new cassava cultivars for disease resistance under defined conditions.

DNA, Viral↗
PubMed1975

The effect of double-stranded cowpea mosaic viral RNA on protein synthesis.

The effect of double-stranded cowpea mosaic viral RNA on several in vitro protein synthesizing systems was studied. No inhibitory effect of this RNA at concentrations up to 16 mug/ml was found in wheat germ protein synthesis programmed with cowpea mosaic viral-, alfalfa mosaic viral- or globin 9 S-RNA. At high concentrations of this double-stranded RNA, inhibition of Escherichia coli in vitro protein synthesis programmed with MS-2- and cowpea mosaic viral-RNA was found, whereas at low concentrations its inhibitory effect on rabbit reticulocyte in vitro protein synthesis was strong. The implications of these observations for the suggestions of other authors, based on the study of mammalian protein synthesizing systems, are discussed.

Animals↗