Efficient Reject Options for Particle Filter Object Tracking in Medical Applications.

Reliable object tracking that is based on video data constitutes an important challenge in diverse areas, including, among others, assisted surgery. Particle filtering offers a state-of-the-art technology for this challenge. Becaise a particle filter is based on a probabilistic model, it provides explicit likelihood values; in theory, the question of whether an object is reliably tracked can be addressed based on these values, provided that the estimates are correct.

Genomic structure of new Tunisian peach latent mosaic viroid variants.

Peach latent mosaic viroid (PLMVd) is a single-stranded circular RNA that do not code for proteins and ranges in size from 335 to 351 nucleotides. It mainly infects peach. In this study, the sequence of 20 complete cDNA clones derived from seven PLMVd isolates detected in five Tunisian peach cultivars was analysed in 3 steps: primary structure, phylogeny and secondary structure.

Molecular features of new Peach Latent Mosaic Viroid variants suggest that recombination may have contributed to the evolution of this infectious RNA.

Nucleotide sequences of a broad range of Peach Latent Mosaic Viroid (PLMVd) variants were determined. The variants were isolated from peach, pear, and almond tree samples collected in Tunisia. Sequence analysis confirmed the high variability of PLMVd, as no less than 119 new variants were identified.

Detection and epidemiological characteristics of peach latent mosaic viroid in Tunisia.

A rapid and sensitive assay was developed for the detection and identification of Peach latent mosaic viroid (PLMVd) by reverse transcription-polymerase chain reaction (RT-PCR) in infected tissues from Tunisian orchards. The test was initially performed by using total RNA preparations from selected isolates and then applied on total RNA preparations from leaf or bark tissues of fruit trees collected in 2003 in 20 orchards in the North of Tunisia and the Sahel. PLMVd occurred in peach and pear trees.

Peach latent mosaic viroid Detected for the First Time on Almond Trees in Tunisia.

Almond (Prunus dulcis Mill) is an important crop in countries of the Mediterranean area. Until now, among viroids, only Hop stunt viroid (HSVd) is known to infect cultivated almond trees (2). In 2004, a survey of almond trees was carried out in orchards in different regions of Tunisia, a major producing and exporting country of almond.

First Report of Cucurbit aphid-borne yellows virus in Tunisia Causing Yellows on Five Cucurbitacious Species.

Viruses, distributed worldwide on cucurbits, cause severe damage to crops. Virus surveys in 2003 and 2004 were made in all the major cucurbit-growing areas in Tunisia. Large populations of aphids (Aphis gossypii Glover) and severe yellowing symptoms of older leaves of cucurbits were observed in outdoor and under plastic-tunnel cultivation, suggesting the presence of Cucurbit aphid-borne yellows virus (CABYV, genus Polerovirus, family Luteoviridae).

Development of molecular tests for the detection of ILAR and latent viruses in fruit trees.

The detection throughout the year of latent and ILAR viruses in fruit tress by classical serological tests appear to be unreliable. We have developed RT-PCR tests for a reliable detection of latent and ILAR viruses in fruit trees. These assays were then simplified to allow the direct use of crude plant extracts instead of total RNA preparations, and the analyses of pooled samples.

First Report of Pear blister canker viroid, Peach latent mosaic viroid, and Hop stunt viroid Infecting Fruit Trees in Tunisia.

Viroids of fruit trees are plant pathogens distributed worldwide and can cause severe losses and economic damage to crops. A survey of fruit trees was carried out in 17 orchards in the northern and Sahel regions of Tunisia. Samples were collected in field trees of peach (Prunus persica L), pear (Pyrus communis L), and almond (Prunus dulcis Mill.

Development of Real-Time RT-PCR Assay for Detection of Prunus necrotic ringspot virus in Fruit Trees.

A real-time fluorescent reverse-transcriptase polymerase chain reaction (RT-PCR) assay using a short fluorogenic 3' minor groove binder (MGB) DNA hydrolysis probe was developed for the detection of Prunus necrotic ringspot virus (PNRSV) in stone fruit trees. The covalent attachment of the minor groove binder moiety at the 3' end of the probe increased the probe target duplex stability and raised the melting temperature to a range suitable for real-time analysis. The real-time RT-PCR assay correlated well with conventional RT-PCR results for the detection of PNRSV.

First Report of Banana mild mosaic virus Isolated from Plantains (Musa AAB) in Colombia.

Plantains (Musa AAB) are important sources of food and income for millions of people in Colombia and other developing countries. Colombia is the largest producer of plantains (2) and the third largest exporter of bananas in the world. In 2001, plants of 'Dominico-Hartón' plantain showing mild chlorotic streak symptoms were observed in northwestern Colombia.

Development of Real-Time PCR for the Rapid Detection of Episomal Banana streak virus (BSV).

A real-time assay for the detection of episomal Banana streak virus (BSV; strain OL) in banana and plantains that carry integrated BSV sequences is described. Primers specific to the viral DNA were designed using the viral sequence integrated into the cv. Obino l'Ewai genome and the sequence of the genomic DNA of the infecting virus strain OL.

Detection of apple chlorotic leaf spot virus using a 5' nuclease assay with a fluorescent 3' minor groove binder-DNA probe.

The development of a real-time 5' nuclease RT-PCR assay for the detection of apple chlorotic leaf spot virus (ACLSV) from infected plant material is described. A short fluorogenic 3' minor groove binder-DNA hydrolysis probe was used to circumvent genome variability between isolates and target a short conserved sequence. The covalent attachment of the minor groove binder moiety at the 3' end of the probe increased the probe/target duplex stability and raised the melting temperature to a range suitable for real-time analysis.

[Neonatal type 1 pneumococcal meningitis and maternal septicemia].

The most common organisms in neonatal meningitis are group B streptococcus and Gram negative enteric bacteriae. Although Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae are the most frequent causes of meningitis in infancy and childhood, they are uncommon in newborns. We report one case of neonatal meningitis and maternal septicemia.

Detection of Apple Stem Grooving Virus in Dormant Apple Trees with Crude Extracts as Templates for One-Step RT-PCR.

Partial nucleotide sequences of amplification products obtained from four European apple stem grooving virus (ASGV) isolates using degenerate primers showed 80 to 85% similarity with the published ASGV sequence of a Japanese strain but 98 to 100% identities among themselves. Based on these sequences, two ASGV-specific primers (ASGV4F-ASGV4R) were designed to amplify a 574-bp fragment located in the putative viral RNA polymerase. With these primers, six European and five American ASGV isolates, maintained in herbaceous hosts (Chenopodium quinoa, Nicotiana glutinosa, and N.

The nucleotide sequence and genome organization of the whitefly transmitted sweetpotato mild mottle virus: a close relationship with members of the family Potyviridae.

Primers corresponding to conserved regions in the RNA-dependent RNA polymerase and the RACE procedure led to the cloning of the complete sweetpotato mild mottle virus (SPMMV) RNA genome. The assembled SPMMV genomic sequence was 10,818 nucleotides in length with a polyadenylated tract at the 3' terminus. The structure and organization of the SPMMV genome appear to be similar to those of potyviruses and rymoviruses.

Differentiation Among Potyviruses Infecting Sweet Potato Based on Genus-and Virus-Specific Reverse Transcription Polymerase Chain Reaction.

Knowledge of virus diseases affecting sweet potato has been complicated due to the frequent occurrence of mixed infections and difficulties in isolating and purifying sweet potato viruses. A combined assay of reverse transcription and polymerase chain reaction (PCR) utilizing degenerate genus-specific primers POT1 and POT2 was applied to 18 sweet potato clones from China. The primers were designed to amplify the variable 5' terminal region of the potyvirus coat protein gene.

Evidence for the assignment of two strains of SPLV to the genus Potyvirus based on coat protein and 3' non-coding region sequence data.

The use of potyvirus-specific primers and subsequent application of the RACE procedure allowed the cloning of the 3' terminal 1088 nucleotides of the genomic RNA of the Taiwan isolate of sweetpotato latent virus (SPLV-T) and the 3' genomic 1085 nucleotides of a SPLV-like virus from China (SPLV-CH). The sequence of an internal part of the presumptive nuclear inclusion b gene was also determined for both isolates. Detailed sequence analyses revealed the presence of consensus motifs which indicated that SPLV-CH and SPLV-T should be regarded as members of the genus Potyvirus.

Determination of the taxonomic position and characterization of yam mosaic virus isolates based on sequence data of the 5'-terminal part of the coat protein cistron.

The sequences of the N-terminal part of the coat protein cistron from six isolates of yam mosaic virus (YMV-TOG, YMV-COT, YMV-12, YMV-CAR, YMV-BU1 and YMV-BU2) were determined. The analysis of the deduced amino acid sequences revealed the presence of consensus motifs characteristic of the potyvirus genus supporting the classification of YMV as a potyvirus member. The alignment of the N-terminal part of the coat protein of YMV-TOG, YMV-COT, YMV-12 and YMV-CAR showed that they were identical in size (152 aa) while YMV-BU1 and YMV-BU2 were shorter (140 aa) due to a deletion of 12 aa.

Molecular evidence that the whitefly-transmitted sweetpotato mild mottle virus belongs to a distinct genus of the Potyviridae.

Complementary DNA representing 2 108 nucleotides at the 3' end of the genomic RNA of the whitefly-transmitted sweetpotato mild mottle virus (SPMMV) was cloned after PCR. Sequence analysis revealed an open reading frame of 1 797 nucleotides which codes for a protein of 599 amino acids, followed by a 3' non-coding region of 311 nucleotides. Alignment of the deduced amino acid sequence with corresponding sequences of other members of the Potyviridae demonstrated that part of the presumptive RNA-dependent RNA polymerase and the coat protein coding regions of SPMMV are found at the 3' end of its genome, in that order.

The complete nucleotide sequences of the coat protein cistron and the 3' non-coding region of a newly-identified potyvirus infecting sweetpotato, as compared to those of sweetpotato feathery mottle virus.

Complementary DNA representing 728 nucleotides of the 3' end of the genomic RNA of sweetpotato virus G (SPV-G) a newly-identified potyvirus infecting sweetpotato, was cloned and sequenced. This sequence was combined with that previously determined for the 5' terminal part of the coat protein cistron of the virus. The whole sequence contained a single open reading frame (ORF) of 1065 nucleotide, with the capacity to encode a coat protein of 355 amino acids, significantly larger than that of other potyviruses.

Identification of a sweet potato feathery mottle virus isolate from China (SPFMV-CH) by the polymerase chain reaction with degenerate primers.

Four degenerate oligonucleotide primers derived from conserved regions of the genome of potyviruses have been designed. A combined assay of reverse transcription and the polymerase chain reaction utilizing these primers on total RNA extracted from Ipomoea purpurea infected with a sweet potato feathery mottle virus isolate from China (SPFMV-CH), amplified a 1.35 kb and a 830 bp fragment.

Synthesis and characterization of DNA complementary to carnation mottle virus RNA.

DNA complementary to carnation mottle virus-RNA (CarMV RNA) was synthesized using the reverse transcriptase of avian myeloblastosis virus (AMV) as enzyme, and an hydrolysate of calf thymus DNA as primer. After purification steps that included self-annealing and hydroxyapatite chromatography, the DNA transcript was more than 99% sensitive to S1 nuclease and hybridized to at least 92% of the CarMV-RNA sequences, but not to heterologous RNA. Therefore, the purified transcript was single stranded and represented almost all CarMV-RNA sequences.

Reverse transcription of turnip yellow mosaic virus RNA primed with calf-thymus DNA hydrolysate: characterization of the purified cDNA product.

Complementary DNA was transcribed from turnip yellow mosaic virus RNA, using the method of Taylor et al. (1). The purified cDNA thus obtained sedimented between 2 and 4 S and was a mostly uniform transcript of template RNA.