Immunization with SmIg, a novel tegument protein from Schistosoma mansoni, fails to induce protection in mice but reduces liver pathology.

Proteins associated with the schistosome tegument are of great importance for the development of new intervention strategies since they may be exposed on the surface of the parasite. Herein, we have isolated a cDNA clone encoding for the Schistosoma mansoni SmIg and its recombinant protein was tested as a potential vaccine candidate. Initially, its amino acid sequence was analysed by bioinformatics and shown to possess an N-terminal signal peptide, a C-terminal transmembrane helix, 4 glycosylation sites, an immunoglobulin conserved domain and 73% similarity with a hypothetical S. japonicum protein of unknown function. SmIg was produced by E. coli as a recombinant protein (rSmIg) and its protective effectiveness was evaluated against S. mansoni infection with 100 cercariae in a murine model. Mice immunized with rSmIg induced an immune response characterized by dominant IgG1 isotype and significant levels of IFN-gamma, TNF-alpha, IL-10 and IL-4. Although immunogenic, the recombinant vaccine failed to induce worm burden reduction when compared to the infected control group. However, rSmIg-immunized mice had significant reductions of liver granuloma volume and fibrosis content by 31.8% and 49%, respectively. In conclusion, SmIg is a new tegument protein from S. mansoni that plays an important role in reducing pathology induced by parasite infection.

Isolation and characterization of HC1: a novel human DNA repair gene.

Nucleotide excision repair (NER) acts on a broad spectrum of large lesions, while base excision repair removes individual modified bases. Although both processes have been well studied in human cells, novel genes involved in these DNA repair pathways have been described. Using a heterologous complementation approach, we identified a fetal human cDNA that complemented two Escherichia coli mutants that are defective in 3-methyl adenine glycosylase and in three endonucleases, all of which are enzymes with important roles in base excision repair. The central cDNA open reading frame complemented NER mutant strains and promoted an increase in survival rate of bacteria exposed to UV light. The corresponding protein was able to restore nucleotide-excision-repair activity when added to a cell extract from Chinese hamster ovary cells deficient in the ERCC1 protein, an enzyme known to promote incision at the 5' end of the lesion during NER. In contrast, that protein was not able to complement XPG Chinese hamster ovary cells deficient in the 3' incision step of NER. These data indicate a new human repair gene, which we named HC1; it is involved in the recognition of two kinds of DNA lesions and it contributes to the 5' DNA incision step in NER.

Analysis of DNA polymerase activity in vitro using non-radioactive primer extension assay in an automated DNA sequencer.

Although different DNA polymerases have distinct functions and substrate affinities, their general mechanism of action is similar. Thus, they can all be studied using the same technical principle, the primer extension assay employing radioactive tags. Even though fluorescence has been used routinely for many years for DNA sequencing, it has not been used in the in vitro primer extension assay. The use of fluorescence labels has obvious advantages over radioactivity, including safety, speed and ease of manipulation. In the present study, we demonstrated the potential of non-radioactive in vitro primer extension for DNA polymerase studies. By using an M13 tag in the substrate, we can use the same fluorescent M13 primer to study different substrate sequences. This technique allows quantification of the DNA polymerase activity of the Klenow fragment using different templates and under different conditions with similar sensitivity to the radioactive assay.

Resistance of Sugarcane Cultivars to Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae).

The spittlebug Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) is one of the most important pests of the sugarcane crop in Brazil. Despite of its importance, there is currently a lack of information regarding sugarcane cultivars' resistance to the spittlebug. Therefore, our objective was to evaluate the response of sugarcane genotypes to this species. Two experiments were carried out under laboratory conditions using a random block design with treatments in a factorial arrangement of 2 × 13 (experiment 1) and 2 × 12 (experiment 2), with six replicates. The first factor included two levels of infestation (infested and noninfested plants with spittlebugs), while the second consisted of the cultivars. Nymph survival varied from 47.9 to 84.5%, indicating that there are different levels of antibiosis to M. fimbriolata among the tested cultivars. The highest degree of antibiosis was found in cultivars IACSP96-7586 and IACSP96-2008, in which nymph survival was close to 48%. IACSP96-7586 also presented some degree of tolerance, but IACSP96-7569 and IACSP97-6682 stood out as the most tolerant cultivars to the pest, showing the lowest reduction in weight of aboveground biomass. On average, spittlebug infestations caused a significant reduction in relative leaf chlorophyll content and aboveground biomass weight.

DNA repair in Corynebacterium model.

Corynebacterium spp. are a group of Gram-positive bacteria that includes plant and animal pathogens, nonpathogenic soil bacteria, and saprophytic species. Our understanding of these organisms is still poor compared with that of other bacterial organisms, but new insights offered by genome sequence data and the elucidation of gene content has provided clues about the nature, genome stability, pathogenicity and virulence of these organisms. We compared 15 Corynebacterium genomes, from pathogenic and nonpathogenic species, focusing on DNA repair genes. DNA repair is a mechanism of great importance in the maintenance of the genomic stability of any organism; inefficiency of this system can promote genomic instability and lead to death. This vulnerability makes it an interesting target in the study of means to control infectious organisms. We found that nucleotide excision repair (NER) was the only pathway whose involved genes were found in all species, suggesting that DNA integrity can be primarily maintained by NER. Recombination repair (RR) is also a well conserved pathway and most RR genes exist commonly in Corynebacterium spp. Absence of recCD genes was also shared by all species, contributing to prevent genome inversions and favoring genomic stability. Mismatch repair (MMR) appeared to be missing, although some genes in this pathway, such mutT, mutY and mutL, are present. Base excision repair (BER) and direct repair pathways are not conserved pathways, since the genes are not shared by all members; however, the existence of some seems to be enough to ensure pathway activity. An interesting fact is the persistence/acquisition of some repair genes in some species, suggesting an important role in DNA maintenance and evolution. These genes can be important targets in the investigation of the role of DNA repair in the pathogenicity of Corynebacterium species and be used as targets in therapeutic intervention. Phylogenetic analysis of uvrABC NER genes showed a pattern of clusters, in which most groups remained fixed. In general, the presence or inexistence of repair genes was shared by all the species we analyzed, and the loss or acquisition of certain DNA repair genes seems to have been an ancestral event.

Efeito de pós vegetais sobre sitophilus zeamais (mots., 1855) (coleoptera: curculionidae) / Effect of plant powders on Sitophilus zeamais (mots., 1855) (Coleoptera: Curculionidae)

Objetivou-se testar a atividade inseticida de pós vegetais em Sitophilus zeamais. Foram testados os pós de Anadenanthera colubrina (folhas); Annona muricata (sementes); Azadirachta inidica (folhas e flores); Caesalpinia pyramidalis (folhas), Chenopodium ambrosioides (folhas e flores); Cymbopogon sp.(folhas); Cymbopogon citratus (folhas); Momordica charantia (folhas e frutos); Piper nigrum (sementes); e Ricinus communis (folhas). Além disso, avaliou-se o potencial inseticida de folhas e flores de C. ambrosioides em diferentes dosagens. Na avaliação de repelência foi estabelecido um índice de preferência, e utilizado o teste t para comparação das médias das espécies vegetais. Também foi realizada a comparação das médias das plantas que foram classificadas como repelentes. Para avaliação da mortalidade, procedeu-se a análise de variância e a comparação das médias pelo teste de Tukey e também o teste t para comparação das médias dos tratamentos C. ambrosioides e P. nigrum. Os dados de emergência foram analisados pelo teste de Tukey. Para avaliar os dados de mortalidade, ocasionados por C. ambrosioides, determinou-se a CL50 utilizando a análise de Probit. Os dados de emergência foram verificados pela análise de regressão. As plantas que provocaram repelência foram Cymbopogon sp., C. citratus e C. ambrosioides. A planta que mais afetou a sobrevivência da praga foi C. ambrosioides, que provocou mortalidade total dos insetos infestantes e nenhuma emergência. Adultos de S. zeamais são mais suscetíveis a concentração de 0,125 g do pó de C. ambrosioides.

Effect of plant powders on Sitophilus zeamais (Mots., 1855) (Coleoptera: Curculionidae). The objective of the present study was to test the insecticidal activity of vegetable powders on Sitophilus zeamais. Powders of Anadenanthera colubrina (leaves); Annona muricata (seed); Azadirachta inidica(leaves and flowers);Caesalpinia pyramidalis(leaves);Chenopodium ambrosioides (leaves and flowers);Cymbopogon sp. (leaves);Cymbopogon citratus (leaves); Momordica charantia (leaves and fruits);Piper nigrum (seed); andRicinus communis (leaves) were evaluated. In addition, we evaluated the insecticidal potential of leaves and flowers of C. ambrosioidesat different dosages. In the evaluation of repellency a preference index was established, and the t test was used to compare the means of plant species. The means of plants that were classified as repellent were also compared. To assess mortality, we proceeded with the analysis of variance and comparison of means by Tukey test and also the t test for comparing the means of the C. ambrosioides and P. nigrum treatments. The emergence data were analyzed by Tukey test. To evaluate the data on mortality caused by C. ambrosioides, the CL50 was determined using Probit analysis. The emergence data were verified by regression analysis. Plants that caused repellency were Cymbopogon sp., C. citratusand C. ambrosioides. The plant that most affected the survival of the pest wasC. ambrosioides, which caused total mortality of insect infestations and no adult emergence. Adults of S. zeamaisare most susceptible to the concentration of 0.125 g ofC. ambrosioides powder.

Primary lipomatous tumors of the cardiac valves.

A tricuspid valve mass was identified on echocardiogram in a 69-year-old man with ischemic heart disease, chronic obstructive pulmonary disease, pulmonary embolism, and pneumonia; he died with progressive respiratory insufficiency. The abnormal mass was ascribed initially to infective endocarditis, and the diagnosis at autopsy was fibrolipoma, a benign tumor. Although rare, valve tumors should be included in the differential diagnosis of abnormal valve masses identified on echocardiogram.

Analysis of DNA polymerase activity in vitro using non-radioactive primer extension assay in an automated DNA sequencer

Although different DNA polymerases have distinct functions and substrate affinities, their general mechanism of action is similar. Thus, they can all be studied using the same technical principle, the primer extension assay employing radioactive tags. Even though fluorescence has been used routinely for many years for DNA sequencing, it has not been used in the in vitro primer extension assay. The use of fluorescence labels has obvious advantages over radioactivity, including safety, speed and ease of manipulation. In the present study, we demonstrated the potential of non-radioactive in vitro primer extension for DNA polymerase studies. By using an M13 tag in the substrate, we can use the same fluorescent M13 primer to study different substrate sequences. This technique allows quantification of the DNA polymerase activity of the Klenow fragment using different templates and under different conditions with similar sensitivity to the radioactive assay.