The capsule of Streptococcus pneumoniae contributes to virulence in the insect model Manduca sexta.

The polysaccharide capsule of Streptococcus pneumoniae is one of the most important virulence factors responsible for human infections and in mouse infection models as well. Larvae of Manduca sexta were used as an alternative animal model in order to test the impact of the pneumococcal capsule on virulence in the insect host. The unencapsulated S. pneumoniae strain R6 was able to cause disease and induce killing in the larvae, and similar results were obtained with related commensal species. However, using the same dose of S. pneumoniae, encapsulated strains including the type 2 D39 strain, the progenitor of R6, and genetically unrelated S. pneumoniae strains of serotype 2, 4, 6B, 23F and 19A, all had increased virulence potential compared to the R6 strain. Between 20 and 70% of the larvae were affected after 96 h compared to 12% observed with R6. Two type 6B S. pneumoniae strains were more virulent compared to the other strains. S. pneumoniae R6 transformants producing the type 6B capsule showed a similar elevated disease potential, confirming the contribution of the pneumococcal polysaccharide capsule to virulence in M. sexta.

Effects of two different deep digital flexor tenotomy techniques on distal articular angles of equine cadaver forelimbs / Efeito de duas técnicas de tenotomia do flexor digital profundo sobre os ângulos articulares distais dos membros anteriores de equinos: estudo post-mortem

Deep digital flexor (DDF) tenotomy is a technique employed for years to treat selected disorders of the musculoskeletal system in horses. Although two different surgical approaches (i.e. mid-metacarpal and pastern) have been described for performing the procedure, in vitro quantitative data regarding the modifications induced by either technique on the distal articular angles is lacking. Therefore, the purpose of the study reported here was to investigate the viability of a proposed biomechanical system of induced-traction used to compare the two DDF tenotomy techniques by measuring the distal articular angles of equine cadaver forelimbs. Ten pairs of forelimbs were collected and mounted to a biomechanical system developed to apply traction at the toe level. Dorsal articular angles of the metacarpophalangeal (MP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints were determined by geometric lines on radiographs taken before and after performing each technique. Comparisons between each tenotomy group and its own control, for each joint, and between the two tenotomy groups using as variable the difference between the tenotomy and control groups were tested. Despite the lack of statistical significance, the DDF tenotomy technique at the pastern level produced extension, to a lesser and greater extent, of the PIP and DIP joints, respectively when compared to the mid-metacarpal level. No remarkable differences could be observed for the MP joint. The developed traction-induced biomechanical construct seemed to be effective in producing valuable quantitative estimations of the distal articular angles of equine cadaver forelimbs subjected to different DDF tenotomy techniques.

A tenotomia do flexor digital profundo (FDP) é uma das técnicas cirúrgicas empregadas para o tratamento de algumas anormalidades osteomusculares, como as deformidades flexurais e a laminite em equinos. Embora diferentes acessos cirúrgicos (i.e. terço médio do metacarpo e quartela) possam ser utilizados, informações quantitativas obtidas in vitro, referentes aos ângulos articulares distais estabelecidos após a execução de ambos os acessos não são conhecidas. Dessa forma, o objetivo deste trabalho foi estudar a viabilidade de um sistema biomecânico de tração induzida na comparação de duas técnicas de tenotomia do FDP por meio da mensuração dos ângulos articulares distais em peças anatômicas de equinos. Dez pares de membros anteriores foram coletados e montados em um sistema biomecânico de tração induzida aplicada na região da pinça do casco. Os ângulos articulares dorsais das articulações metacarpo falangeana (MF), interfalangeana proximal (IFP) e interfalangeana distal (IFD) foram determinados através de linhas geométricas traçadas com base no exame radiográfico realizado antes e após a realização de cada técnica. Comparações entre cada técnica e seu respectivo controle, para cada articulação, e entre as duas técnicas, utilizando as diferenças angulares obtidas antes e após cada técnica, foram testadas. Embora não se tenha obtido diferença estatisticamente significativa, a técnica de tenotomia do FDP ao nível da quartela produziu um maior e menor grau de extensão das articulações IFD e IFP, respectivamente, quando comparado à técnica no terço médio do metacarpo. Diferenças inexpressivas foram observadas na articulação MF. O sistema biomecânico de tração induzida se mostrou eficiente na determinação quantitativa dos valores aproximados das angulações articulares distais de membros anteriores de equinos submetidos às duas técnicas de tenotomia do FDP.

Genome of Streptococcus oralis strain Uo5.

Streptococcus oralis, a commensal species of the human oral cavity, belongs to the Mitis group of streptococci, which includes one of the major human pathogens as well, S. pneumoniae. We report here the first complete genome sequence of this species. S. oralis Uo5, a high-level penicillin- and multiple-antibiotic-resistant isolate from Hungary, is competent for genetic transformation under laboratory conditions. Comparative and functional genomics of Uo5 will be important in understanding the evolution of pathogenesis among Mitis streptococci and their potential to engage in interspecies gene transfer.

The genome of Streptococcus mitis B6--what is a commensal?

Streptococcus mitis is the closest relative of the major human pathogen S. pneumoniae. The 2,15 Mb sequence of the Streptococcus mitis B6 chromosome, an unusually high-level beta-lactam resistant and multiple antibiotic resistant strain, has now been determined to encode 2100 genes. The accessory genome is estimated to represent over 40%, including 75 mostly novel transposases and IS, the prophage phiB6 and another seven phage related regions. Tetracycline resistance mediated by Tn5801, and an unusual and large gene cluster containing three aminoglycoside resistance determinants have not been described in other Streptococcus spp. Comparative genomic analyses including hybridization experiments on a S. mitis B6 specific microarray reveal that individual S. mitis strains are almost as distantly related to the B6 strain as S. pneumoniae. Both species share a core of over 900 genes. Most proteins described as pneumococcal virulence factors are present in S. mitis B6, but the three choline binding proteins PcpA, PspA and PspC, and three gene clusters containing the hyaluronidase gene, ply and lytA, and the capsular genes are absent in S. mitis B6 and other S. mitis as well and confirm their importance for the pathogenetic potential of S. pneumoniae. Despite the close relatedness between the two species, the S. mitis B6 genome reveals a striking X-alignment when compared with S. pneumoniae.

Ocorrência de doenças oftalmológicas em eqüinos utilizados para tração urbana na cidade de Londrina, PR / Occurrence of ophthalmologic diseases in horses used for urban cart hauling in Londrina, PR, Brazil

Com o objetivo de verificar a ocorrência de doenças oculares em eqüinos utilizados para serviços de tração urbana na cidade de Londrina, PR, foram revistos os registros clínicos de 805 eqüinos atendidos no Hospital Veterinário da Universidade Estadual de Londrina no período entre 1992 e 2007. Nesses registros clínicos foram verificados 25 casos de doenças oftalmológicas (3,1%), compostas por 12 casos (48 por cento) de doenças da córnea, seis casos (24%) de catarata, seis casos (24%) de doenças da conjuntiva (paralelas a outras enfermidades oculares ou não), dois casos (8%) de uveíte recorrente eqüina, um caso de carcinoma de células escamosas da terceira pálpebra, um caso de lesão crônica de pálpebra, com necrose e perda do globo ocular, e um caso de Phthisis bulbi (4% cada). A principal causa das enfermidades oftalmológicas diagnosticadas nesses animais foi traumática (36% dos casos). A maioria das doenças diagnosticadas neste estudo, se não tratadas adequadamente, pode resultar em cegueira e, conseqüentemente, pode inutilizar o animal para uso em tração urbana. Isso reforça a necessidade de conscientização dos carroceiros sobre a importância e a profilaxia dessas enfermidades.

The clinical records of 805 horses admitted to the Veterinary Hospital of the State University of Londrina between 1992 and 2007 were reviewed in order to establish the occurrence of ophthalmologic diseases in horses used for hauling carts in Londrina, Paraná, Brazil. Among these records, there were 25 ophthalmologic cases (3.1%), composed of 12 cases (48%) of corneal diseases, six cases (24%) of cataracts, six cases (24%) of conjunctival diseases (associated or not to other lesions), two cases (8%) of recurrent equine uveitis, one case of squamous cell carcinoma of the third eyelid, one case of chronic necrotic eyelid lesion with loss of the eye globe and one case of phthisis bulbi (4% each). Trauma was the most important etiology for eye diseases diagnosed in this study (36%). Most of the ophthalmologic diseases seen in this study may cause blindness if not adequately treated, and this might prevent the animal from performing draught activities. Therefore, this study helps to emphasize the need of continuously making cart owners aware of the importance and prevention of such conditions.

Occurrence of antibodies against Leptospira spp. in horses of the urban area of Londrina, Paraná, Brazil.

A total of 320 horses were studied in this paper, both male and female, between two and 17 years of age, which were used for traction of wagons in the urban area of the municipality of Londrina (PR). These animals were kept, after their daily work, in abandoned areas or plots, in the outskirts of the urban area of the city. When these animals were attended by the veterinarians, between 1996 and 2005, none of them presented symptoms suggesting leptospirosis. The most frequent reasons for the visit were loss of weight, unwillingness for work, parasitism, laminess, and wounds. Microscopic Seroagglutination Test (SAM), with 22 Leptospira serovars, was performed in sera sample from all these animals. The aim of this study was to investigate the occurrence of antibodies against Leptospira spp. in horses from the urban area of Londrina (PR). From the samples tested, 214 (66.88%) were considered positive, with titers between 100 and 3200, being that 49 (22.90%) presented antibodies against a single serovar of Leptospira, and 165 (77.10%) samples presented antibodies against two or more serovars simultaneously, where in 88 (53.33%) it was possible to characterize the most likely probable serovar. Antibodies against the serovar Icterohaemorrhagiae were detected in 32 (23.36%) animals.

Occurrence of antibodies against Leptospira spp. in horses of the urban area of Londrina, Paraná, Brazil

A total of 320 horses were studied in this paper, both male and female, between two and 17 years of age, which were used for traction of wagons in the urban area of the municipality of Londrina (PR). These animals were kept, after their daily work, in abandoned areas or plots, in the outskirts of the urban area of the city. When these animals were attended by the veterinarians, between 1996 and 2005, none of them presented symptoms suggesting leptospirosis. The most frequent reasons for the visit were loss of weight, unwillingness for work, parasitism, laminess, and wounds. Microscopic Seroagglutination Test (SAM), with 22 Leptospira serovars, was performed in sera sample from all these animals. The aim of this study was to investigate the occurrence of antibodies against Leptospira spp. in horses from the urban area of Londrina (PR). From the samples tested, 214 (66.88 percent) were considered positive, with titers between 100 and 3200, being that 49 (22.90 percent) presented antibodies against a single serovar of Leptospira, and 165 (77.10 percent) samples presented antibodies against two or more serovars simultaneously, where in 88 (53.33 percent) it was possible to characterize the most likely probable serovar. Antibodies against the serovar Icterohaemorrhagiae were detected in 32 (23.36 percent) animals.

Foram estudados 320 eqüinos, machos e fêmeas com idade entre dois a 17 anos, utilizados para tração de carroças na área urbana do município de Londrina (PR). Estes animais eram mantidos, após a jornada diária de serviço, em áreas ou terrenos baldios, localizados na periferia da área urbana do município. Por ocasião do atendimento, realizado entre 1996 e 2005, no Hospital Veterinário da Universidade Estadual de Londrina, nenhum dos animais apresentou sintomas sugestivos de leptospirose, sendo os motivos mais freqüentes, o emagrecimento, a indisposição para o trabalho, a verminose, problemas no sistema locomotor e feridas. A prova de soroaglutinação microscópica (SAM), com 22 sorovares de Leptospira, foi realizada em amostra de soro de todos os animais. O objetivo deste trabalho foi investigar a ocorrência de anticorpos contra Leptospira spp. em eqüinos da área urbana do município de Londrina. Foram consideradas positivas 214 (66,88 por cento) amostras de soros com títulos entre 100 e 3200, sendo em 49 (22,90 por cento) detectadas anticorpos contra um único sorovar de Leptospira e em 165 (77,10 por cento) amostras com anticorpos contra dois ou mais sorovares simultâneamente, sendo em 88 (53,33 por cento) destes caracterizado o sorovar mais provável. Anticorpos contra o sorovar Icterohaemorrhagiae foram detectados em 32 (23,36 por cento) animais.

Diversity of bacteriocins and activity spectrum in Streptococcus pneumoniae.

The production of bacteriocins can be favorable for colonization of the host by eliminating other bacterial species that share the same environment. In Streptococcus pneumoniae, the pnc (blp) locus encoding putative bacteriocins, immunity, and export proteins is controlled by a two-component system similar to the comCDE system required for the induction of genetic competence. A detailed comparison of the pnc clusters of four genetically distinct isolates confirmed the great plasticity of this locus and documented several repeat sequences. Members of the multiple-antibiotic-resistant Spain23F-1 clone, one member of the Spain9V-3 clone, sensitive 23F strain 2306, and the TIGR4 strain produced bactericidal substances active against other gram-positive bacteria and in some cases against S. pneumoniae as well. However, other strains did not show activity against the indicator strains despite the presence of a bacteriocin cluster, indicating that other factors are required for bacteriocin activity. Analysis of strain 2306 and mutant derivatives of this strain confirmed that bacteriocin production was dependent on the two-component regulatory system and genes involved in bacteriocin transport and processing. At least one other bacteriocin gene, pncE, is located elsewhere on the chromosome and might contribute to the bacteriocin activity of this strain.

Microarray analysis of expressed sequence tags from haustoria of the rust fungus Uromyces fabae.

Rust fungi are plant parasites which colonise host tissue with an intercellular mycelium that forms haustoria within living plant cells. To identify genes expressed during biotrophic growth, EST sequencing was performed with a haustorium-specific cDNA library from Uromyces fabae. One thousand seventeen ESTs were generated, which assembled into 530 contigs. Several of the most frequently represented sequences in the EST database were identical to the in planta induced genes (PIGs) identified previously (Hahn, M., Mendgen, K., 1997. Characterisation of in planta-induced rust genes isolated from a haustorium-specific cDNA library, Mol. Plant-Microbe Interact. 10, 427-437). Virus-encoded sequences were identified, providing evidence for two novel RNA mycoviruses in U. fabae. Microarray hybridisation revealed many cDNAs that were significantly activated in rust-infected leaves compared to germinated uredospores. Very strong in planta expression was found for two PIGs encoding putative metallothioneins. Furthermore, several genes involved in ribosome biogenesis and translation, glycolysis, amino acid metabolism, stress response, and detoxification showed an increased expression in the parasitic mycelium. These data indicate a strong shift in gene expression in rust fungi between germination and the biotrophic stage of development.

Mosaic genes and mosaic chromosomes-genomic variation in Streptococcus pneumoniae.

The genome sequences of two strains of Streptococcus pneumoniae, one of the major human pathogens, are currently available: that of the nonencapsulated laboratory strain R6, the origin of which dates back to the early 20th century, and of the serotype 4 TIGR strain isolated recently. The two genomes are not only different in size (2 versus 2.16 Mb) but differ also by approximately 10% of their genes, many of which being organized in large clusters. Their strain-specific genes and gene clusters are described here. The R6 genome contains 69 kb organized in six large regions that are absent from the TIGR strain, which in turn contains an extra 157kb in twelve clusters compared to R6. In addition, the TIGR strain contains 13 clusters of 4 kb and larger that are not shared by a variety of genetically different S. pneumoniae strains. Many regions bear signs of gene transfer events such as the presence of insertion sequences, transposable elements, and putative site-specific integrases/recombinases. Three strain-specific regions are devoted to genes encoding proteins with the cell wall anchor motif LPXTG which are important for the interaction with host cells and appear to be highly variable, similar to cell wall-associated choline-binding proteins.

Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content.

The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s(-1), in steps of 1 mm s(-1), for a total distance of 250 mm. The prototype was evaluated with a phantom of the third metacarpal bone made of perspex and aluminium, and in vitro with a transverse slice of the third metacarpal bone of a horse. The tests showed that the prototype has an accuracy and precision of, approximately, 10% and 6%, respectively, for a 6 s acquisition time. Preliminary studies carried out in three foals from birth to one year of age indicated that the prototype is well suited to in vivo and in situ analysis of the BMD of the third metacarpal bones of horses, making it possible to evaluate the changes of BMD levels on a monthly basis. Also, results indicated an exponential behaviour of the BMD curve during the first year of life of the studied horses.

A XerD recombinase with unusual active site motifs in Streptococcus pneumoniae.

XerD belongs to the site specific recombinases of the integrase family of proteins that catalyze recombination events via a phosphotyrosine intermediate. Sequence alignments and crystal structure resolution of E. coli XerD and related enzymes demonstrated the importance of four conserved amino acids R-H-R-H that are spaced along the C-terminal domain in addition to a conserved K and the active site Y, all of which have been implicated in catalysis. The deduced amino acid sequence of the putative S. pneumoniae XerD contained three unique replacements at the conserved positions resulting in L-Q-R-L; moreover, the active site Y was the penultimate amino acid residue, and the extreme C-terminal region suggested to be involved in interaction of E. coli XerD with XerC was lacking. Severe growth defects in a loss-of-function xerD mutant are consistent with an important in vivo function of the S. pneumoniae XerD protein. Highly related xerD genes with similar unusual amino acid replacements were found in S. mitis, S. mutans and S. pyogenes but not in other Gram-positive bacteria, although the genetic environment was very similar in many species. There are at least another four genes in the S. pneumoniae KNR_7/87 genome encoding Xer related peptides, one of which was identified as the xerC homologue. The xerD and xerC genes were present in a sample of 20 S. pneumoniae strains whereas the other xer genes appear to be absent in some of the strains and are more closely related to integrases of phage and transposon origin.