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L M Moreira

Publications and source records attributed to L M Moreira.

12 recordsLinked to original sources
PubMed2002

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities.

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

Gene Order↗
PubMed2002

Gellan gum biosynthesis in Sphingomonas paucimobilis ATCC 31461: genes, enzymes and exopolysaccharide production engineering.

The commercial gelling agent, gellan, is an extracellular polysaccharide (EPS) produced by Sphingomonas paucimobilis ATCC 31461. In recent years, significant progress in understanding the relationship between gellan structure and properties and elucidation of the biosynthesis and engineering of this recent product of biotechnology has been made. This review focuses on recent advances in this field. Emphasis is given to identification and characterization of genes and enzymes involved, or predicted to be involved, in the gellan biosynthetic pathway, at the level of synthesis of sugar-activated precursors, of the repeat unit assembly and of gellan polymerization and export. Identification of several genes, biochemical characterization of the encoded enzymes and elucidation of crucial steps of the gellan pathway indicate that possibilities now exist for exerting control over gellan production at any of the three levels of its biosynthesis. However, a better knowledge of the poorly understood steps and of the bottlenecks and regulation of the pathway, the characterization of the composition, structure and functional properties of gellan-like polymers produced either by the industrial strain under different culture conditions or by mutants are still required for eventual success of the metabolic engineering of gellan production.

Biological Transport↗
PubMed2001

The nodulin vfENOD18 is an ATP-binding protein in infected cells of Vicia faba L. nodules.

Recently we described the novel nodulin gene VfENOD18, whose corresponding transcripts were restricted to the nitrogen-fixing zone III of broad bean root nodules. To characterize VfENOD18 on the protein level, polyclonal antibodies were generated using the purified recombinant VfENOD18 protein produced in Escherichia coli by employing the pMAL-c expression system. These antibodies recognized immunoreactive proteins isolated from indeterminate nodules of different leguminous plants, but also from non-symbiotic tissues of Glycine max and from tissues of Arabidopsis thaliana and Zea mays. Using immunogold labelling the nodulin VfENOD18 was localized to the cytoplasm of infected cells in the nitrogen-fixing zone of broad bean nodules. Due to the homology of the VfENOD18 sequence to that of the ATP-binding protein MJ0577 from the hyperthermophile Methanococcus jannaschii the recombinant VfENOD18 protein was tested for ATP-binding. Using the biotin photoaffinity ATP analogue 8N3ATP[gamma]biotin it could be demonstrated that VfENOD18 is an ATP-binding protein. PCR experiments revealed that the amino acid sequences of the putative C-terminal ATP-binding sites of the VfENOD 18 homologues from Lens culinaris, Vicia hirsuta, Vicia sativa and Vicia villosa were conserved. We propose that VfENOD18 is a member of a novel family of ATP-binding proteins in plants.

Adenosine Triphosphate↗
PubMed2000

Two sibs with duplication of 4q31-->qter due to 3:1 meiotic disjunction and mild phenotype.

Two sibs with duplication of 4q31-->qter due to 3:1 meiotic disjunction and mild phenotype: Clinical and cytogenetic findings in two sibs with partial duplication of 4q31.3-->qter and 21q11.2-->pter are reported. These patients are rare cases of reoccurrence of those partial trisomies due to 3:1 segregation of a maternal balanced translocation. A review of the literature reporting cases of trisomy of the 4q31-->qter segment is also made; previously reported cases mostly in addition have deletions of other chromosomes resulting from adjacent segregation of balanced translocation. The findings of our study confirm the high risk for offspring with unbalanced rearrangements in women with reciprocal translocation involving acrocentric and short chromosome segments. The study also points out that duplication of 4q31-->qter may go along with only mild phenotypic findings if there is no significant additional aneuploidy of the other chromosome involved in the rearrangement.

Chromosomes, Human, Pair 21↗
PubMed1997

Comparative genomic analysis of isolates belonging to the six species of the genus Thermus using pulsed-field gel electrophoresis and ribotyping.

Fifty isolates belonging to the six validly described species of the genus Thermus (T. aquaticus, T. filiformis, T. thermophilus, T. scotoductus, T. brockianus, and T. oshimai) isolated from hot springs of different geographical areas were compared using macrorestriction analysis of genomic DNA and ribotyping. With the exception of presumed clones, the macrorestriction patterns of isolates obtained with EcoRI or NdeI were distinct. However, isolates belonging to the same species exhibited similar profiles particularly when they were isolated from the same hot spring. The estimated genomic size of strains of the Thermus spp. varied between approximately 1.8 and 2.5 Mbp. Ribotyping with BamHI and HindIII produced 30 and 35 distinct ribotypes, respectively. In spite of the variability of the hybridization patterns produced, the ribotypes obtained for isolates belonging to the same species also shared, in general, several fragments of identical size, and these fragments were similar when isolates originated from the same spring.

Bacterial Typing Techniques↗
PubMed1997

Megaplasmids in Thermus oshimai isolates from two widely separated geographical areas: restriction fragment profiling and DNA homology.

Megaplasmid DNA was detected in ten isolates belonging to the recently described thermophilic eubacterial species Thermus oshimai and isolated from hot springs in Portugal (eight isolates) and Iceland (two isolates). The estimated size of the large plasmids purified from T. oshimai SPS-18 from S. Pedro do Sul, Portugal, and from isolate JK-91 from Hveragerdhi-Hengill, Iceland, was 214 and 275 kb, respectively. No sequence homologous to isolate SPS-18 megaplasmid is present in chromosomal DNA as indicated by Southern hybridization analysis. Overall examination of the HindIII fragment profiles of megaplasmid DNAs purified from isolates from the same geographical area gave similar but not always identical restriction profiles on agarose gels. Restriction fragment length polymorphism (RFLP) was higher for megaplasmids present in isolates purified from the Portuguese and Icelandic isolates than for megaplasmids from the same hot spring. Megaplasmid RFLP correlated with previous results obtained on the polymorphism of macrorestriction patterns of whole genomic DNA and with the RFLP of co-resident small plasmid DNA that was found in one half of the isolates examined. The 16-kb HindIII-HindIII fragment from isolate SPS-18 megaplasmid showed DNA-DNA homology with restriction fragments of similar size generated by the large plasmids present in all the other isolates, even in those from hot springs of widely separated geographical areas. This suggests a high degree of sequence conservation in T. oshimai megaplasmids.

DNA, Bacterial↗
PubMed1995

[Efficacy of repeat coronary dilatation in patients with restenosis of the anterior descending artery].

PURPOSE: To analyze the clinical characteristics, acute and long term results of repeat percutaneous transluminal coronary angioplasty (PTCA) for restenosis of the proximal left anterior descending coronary artery (LDA) METHODS: We studied 113 patients, 79% male, mean age 59 years, 49.5% had stable angina, with single vessel proximal LDA disease undergoing repeat PTCA for a first restenosis from January/88 to December/92. We examined the in hospital outcome (success rate and complications) and long term follow up (angina status, occurrence of myocardial infarction (MI), death and need for repeat PTCA or coronary artery bypass graft (CABG) of this subgroup. RESULTS: Primary success was 96%. Complications included: 1% MI, 1% emergency CABG and 1% procedural death. Follow up data (mean 42 months) was available in 102 (94%) out of 109 patients with successful repeat PTCA: 64 (63%) patients were asymptomatic, 5 (5%) had a MI and 28 (27%) required repeat PTCA or CABG. Actuarial 5 year freedom from death was 94%, freedom from death and MI was 91% and freedom from death, MI and repeat PTCA or CABG was 52%. CONCLUSION: Repeat PTCA is an effective treatment for proximal LAD restenosis with a high success rate, low incidence of procedural complications and provides excellent long term cardiac survival, however repeat revascularization is frequently required.

Actuarial Analysis↗
PubMed1978

Trisomy 8 syndrome.

Clinical and dermatoglyphic data on a male patient with complete trisomy 8 are reported and compared with those of other known cases of trisomy 8. The more discriminating findings for this condition are skeletal anomalies, restricted articular function, and speech problems.

Adult↗
PubMed1977

[Satellite association in two trisomic cases of Down's syndrome and in one healthy mother, with acrocentric variants (author's transl)].

The frequency of satellite association of two different acrocentric variants in two trisomic mongols was studied taking in consideration the possible relationship of these chromosomes in the etiology of non-disjunction events. The participation of the two variants and their homologous in satellite associations showed no differences suggesting, randommess in these two families.

Child↗
PubMed1976

[Association of neuromotor retardation and chromosome lqH report of a case].

A case of neuromotor retardation in association with chromosome 1qh's reported. Chromosomes analysis of the patient and three relatives showed increased long arm on the n. degrees 1 chromosome, in all of them. However it is wmphasized that the clinical feautre could be secondary to various non genetics factors, also.

Chromosome Aberrations↗