Humberto Maciel França Madeira

Swine and Poultry Pathogens: the Complete Genome Sequences of Two Strains of Mycoplasma hyopneumoniae and a Strain of Mycoplasma synoviae

This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.

Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.

Phenotypic and Genotypic Characterization of Group B Streptococcal Isolates in Southern Brazil

ABSTRACT One-hundred sixty-eight group B streptococcal (GBS) isolates from a Brazilian hospital were phenotypically and genotypically characterized. Isolates were recovered from human sources from April 2006 to May 2008 and classified as either invasive, noninvasive, or colonizing isolates. Classical methods for serotyping and antibiotic resistance profiling were employed. Clonal groups were also defined by pulsed-field gel electrophoresis (PFGE). Results showed that susceptibility to beta-lactam antimicrobials was predominant among the isolates. Only 4.7% were resistant to erythromycin and clindamycin. The erm(B) gene was widely detected in our GBS isolates, according to our phenotypic results (constitutive macrolide-lincosamide-streptogramin B [cMLSB] resistance phenotype), and the erm(A) gene was also detected in some isolates. MLSB resistance was restricted to strains isolated from patients with noninvasive infections and carriers. Serotype Ia was predominant (38.1%), serotype IV isolates were found at a high frequency (13.1%), and few isolates of serotype III were identified (3%). Pulsed-field gel electrophoresis results revealed a variety of types, reflecting the substantial genetic diversity among GBS strains, although a great number of isolates could be clustered into two major groups with a high degree of genetic relatedness. Three main PFGE clonal groups were found, and isolates sharing the same PFGE type were grouped into different serotypes. Furthermore, in a few cases, isolates from the same patients and possessing the same PFGE type were of different serotypes. These findings could be related to the occurrence of capsular switching by horizontal transfer of capsular genes.

The type III secretion system is necessary for the development of a pathogenic and endophytic interaction between Herbaspirillum rubrisubalbicans and Poaceae

BackgroundHerbaspirillum rubrisubalbicans was first identified as a bacterial plant pathogen, causing the mottled stripe disease in sugarcane. H. rubrisubalbicans can also associate with various plants of economic interest in a non pathogenic manner.ResultsA 21 kb DNA region of the H. rubrisubalbicans genome contains a cluster of 26 hrp/hrc genes encoding for the type three secretion system (T3SS) proteins. To investigate the contribution of T3SS to the plant-bacterial interaction process we generated mutant strains of H. rubrisubalbicans M1 carrying a Tn5 insertion in both the hrcN and hrpE genes. H. rubrisulbalbicans hrpE and hrcN mutant strains of the T3SS system failed to cause the mottled stripe disease in the sugarcane susceptible variety B-4362. These mutant strains also did not produce lesions on Vigna unguiculata leaves. Oryza sativa and Zea mays colonization experiments showed that mutations in hrpE and hrcN genes reduced the capacity of H. rubrisulbalbicans to colonize these plants, suggesting that hrpE and hrcN genes are involved in the endophytic colonization.ConclusionsOur results indicate that the T3SS of H. rubrisubalbicans is necessary for the development of the mottled stripe disease and endophytic colonization of rice.

Maternal group B streptococcal immunization: capsular polysaccharide (CPS)-based vaccines and their implications on prevention.

Group B streptococcal (GBS) capsular polysaccharide (CPS)-based conjugate vaccine, which includes types Ia, Ib, II, III, and V, could potentially prevent neonatal, pediatric, adult, and pregnancy-associated diseases. However, since GBS CPS types included in that vaccine are prevalent serotypes found in North America and Europe, it may not provide the necessary protection for individuals in countries in which other capsular types have been found.

Treponemes Detected in Digital Dermatitis Lesions in Brazilian Dairy Cattle and Possible Host Reservoirs of Infection

ABSTRACT The main pathogenic treponemes causing bovine digital dermatitis were identified from 17 infected herds in southern Brazil for the first time in this study using PCR. We did not find a relationship between treponeme phylogroup composition and clinical classification. Treponema phagedenis was present in all lesions. Rumen fluid was implicated as a reservoir location for these pathogens.

Regulation of gene expression in Mycoplasmas: contribution from Mycoplasma hyopneumoniae and Mycoplasma synoviae genome sequences

This report describes the transcription apparatus of Mycoplasma hyopneumoniae (strains J and 7448) and Mycoplasma synoviae, using a comparative genomics approach to summarize the main features related to transcription and control of gene expression in mycoplasmas. Most of the transcription-related genes present in the three strains are well conserved among mycoplasmas. Some unique aspects of transcription in mycoplasmas and the scarcity of regulatory proteins in mycoplasma genomes are discussed.

New method for early detection of two random amplified polymorphic DNA (RAPD) groups of Staphylococcus aureus causing bovine mastitis infection in Paraná State, Brazil

ABSTRACT The aim of this work was to develop a fast and accurate molecular approach to allow early detection of two RAPD groups of S. aureus causing bovine mastitis. Seventy five S. aureus isolates from infected animals were characterized by RAPD. Genomic fragments isolated from the unique bands present in either group were cloned and sequenced. Based on the DNA sequences, specific primers were designed to allow for the simultaneous detection of either group by multiplex PCR of S. aureus DNA isolated from clinical and subclinical bovine mastitis. Results showed that these proposed primers set could be used to detect various clinical and subclinical S. aureus isolates as well as the detection of the microorganism in bulk milk. Their use as a specific method for effective and early diagnostic tool for S. aureus infection in dairy herds is suggested. Key words : Staphylococcus aureus, molecular markers; subclinical mastitis, clinical mastitis, mastitis detection * Author for correspondence: dicezar.zmv@uol.com.br

Heterologous induction of a predicted promoter sequence for paraquat-inducible genes of Chromobacterium violaceum in response to paraquat compound

(With 1 Figure)The Chromobacterium violaceum is a Gram-negative, free-living betaproteobacterium that dominates a variety of ecosystems in tropical and subtropical regions. Notably, several refined mechanisms related to remarkable and exploitable adaptability have been revealed in the genome prospecting of this bacterium, including biological responses to oxidative stress by predicting of paraquat-inducible proteins ( Brazilian National Genome Project Consortium, 2003). In the cited study, two open reading frames (ORFs) for paraquat-inducible proteins were identified during genome annotation analyses of C. violaceum ATCC 12472, demonstrating a high similarity to sequences of paraquat-inducible genes ( pqi genes) previously characterized in the Escherichia coli bacterium ( Farr and Kogoma, 1991 ). The paraquat-inducible genes are drastically modulated by acting of several oxidizing agents, unleashing a complex cellular response to oxidative stress in a great variety of bacterial strains to minimize deleterious effects of the superoxide radical-generating compounds on the maintenance of the cellular homeostasis (Hungria et al., 2004). Thus, the purpose of the present study was to functionally evaluate the influence of the paraquat compound on the heterologous induction of the predicted promoter sequence for paraquat-inducible genes revealed during genome annotation analyses of the C. violaceum bacterium.Initially, specific primers were designed by using computational program (http://www.idtdncom/SciTools/SciTools.aspx) to flank target sites situated between ORFs CV2550 and CV2551, corresponding to the promoter sequence of paraquat-inducible genes predicted during C. violaceum genome annotation analyses. Sequences of the forward (5’–CGT