ABSTRACTThe diversity ofPseudomonas aeruginosabacteriophages was investigated using a collection of 68 phages isolated from Central Mexico. Most of the phages carried double-stranded DNA (dsDNA) genomes and were classified into 12 species. Comparison of the genomes of selected archetypal phages with extant sequences in GenBank resulted in the identification of six novel species. This finding increased the group diversity by ∼30%. The great diversity of phage species could be related to the ubiquitous nature ofP. aeruginosa.

bIn this work, we isolated and characterized 14 bacteriophages that infect Rhizobium etli. They were obtained from rhizosphere soil of bean plants from agricultural lands in Mexico using an enrichment method. The host range of these phages was narrow but variable within a collection of 48 R. etli strains. We obtained the complete genome sequence of nine phages. Four phages were resistant to several restriction enzymes and in vivo cloning, probably due to nucleotide modifications. The genome size of the sequenced phages varied from 43 kb to 115 kb, with a median size of ϳ45 to 50 kb. A large proportion of open reading frames of these phage genomes (65 to 70%) consisted of hypothetical and orphan genes. The remainder encoded proteins needed for phage morphogenesis and DNA synthesis and processing, among other functions, and a minor percentage represented genes of bacterial origin. We classified these phages into four genomic types on the basis of their genomic similarity, gene content, and host range. Since there are no reports of similar sequences, we propose that these bacteriophages correspond to novel species. Bacteriophages have an enormous impact on the ecology and evolution of bacteria (1-3). It is well-known that bacteriophages are agents of gene mobilization across bacterial populations and that the majority of bacterial genomes harbor prophages as well as individual genes of phage origin (4-6). Conversely, temperate phages often carry bacterial genes as a result of prophage induction and recombination (7,8). Some reports indicate that phages exist for almost every known bacterial species (9). In the case of symbiotic nitrogen-fixing bacteria, such as Sinorhizobium meliloti (10, 11), Rhizobium leguminosarum (12-14), Mesorhizobium spp. (15), and Bradyrhizobium spp. (16), phages have been isolated and characterized, but no genome sequences have been reported. As a consequence, genomic comparisons have not been made. To date, only the complete genome sequence of phage 16-3 of S. meliloti has been determined (17).Lytic and temperate phages that infect rhizobial species have been isolated from soils and from lysogens induced after UV light treatment or mitomycin C exposure (11). The presence of phageresistant and -sensitive strains of Rhizobium suggests that phages play a substantial role in the selection or elimination of certain genotypes (11,(18)(19)(20). For instance, bacteriophages reduce the population density of susceptible strains of Rhizobium trifolii on the root surface, allowing resistant strains to form nodules (21,22). In field experiments, the persistence of genetically modified rhizobia has been explained in part by their resistance to phages (19).In the completely sequenced genomes of Rhizobium etli strains CFN42 and CIAT652 (23, 24), there are some open reading frames (ORFs) with relatively high degrees of identity to bacteriophage genes, such as DNA integrases, DNA transferases, lysozymes, and the small and large subunits of DNA terminase. In this work, we obtained a collection of 14 R. etli ...

The propolis produced by bees are used in alternative medicine for treating inflammation, and infections, presumably due to its antioxidant properties. In this context, five propolis from México were investigated to determine their inhibitory lipid peroxidation properties. The ethyl acetate extract from a red propolis from Chiapas State (4-EAEP) was the most potent (IC50 = 1.42 ± 0.07 μg/mL) in the TBARS assay, and selected for further studies. This extract afforded two new compounds, epoxypinocembrin chalcone (6), and an ε-caprolactone derivative (10), as well as pinostrobin (1), izalpinin (2), cinnamic acid (3), pinocembrin (4), kaempherol (5), 3,3-dimethylallyl caffeate in mixture with isopent-3-enyl caffeate (7a + 7b), 3,4-dimethoxycinnamic acid (8), rhamnetin (9) and caffeic acid (11). The HPLC profile, anti-mycobacterial, and antioxidant properties of this extract was also determined. Most of the isolated compounds were also tested by inhibition of reactive oxygen species (ROS) in challenged mouse bone marrow-derived mast cells (BMMCs), and DPPH. Their anti-inflammatory activity was evaluated by TPA, and MPO (myeloperoxidase) activity by ear edema test in mice. The most potent compounds were 7a + 7b in the TBARS assay (IC50 = 0.49 ± 0.06 μM), and 2 which restored the ROS baseline (3.5 μM). Our results indicate that 4-EAEP has anti-oxidant, and anti-inflammatory properties due to its active compounds, suggesting it has anti-allergy and anti-asthma potential.