Molecular techniques for dicistrovirus detection without RNA extraction or purification

Analysis of bacterial communities associated with potting media

BACKGROUND

Potting media are commonly used by growers in different parts of the world for potted plants, raising seedlings and for improving soil characteristics. This study was conducted to characterize bacterial communities occurring in 13 commercial potting media products originating from seven countries.

FINDINGS

Bacteria were isolated using serial dilution. Identification to the species level was based on phylogenetic analysis of the 16S rRNA gene. The analysis showed the association of 13 bacterial species with the different potting media samples, namely Arthrobacter livingstonensis, Kocuria flava, Leifsonia lichenia, Bacillus vallismortis, Bacillus pumilus, Staphylococcus warneri, Burkholderia phenazinium, Burkholderia sp., Ralstonia pickettii, Rhodanobacter spathiphylli, Rhodanobacter sp., Pseudomonas thivervalensis and Chryseobacterium gallinarum. Bacterial densities in the samples ranged from 8 × 10(7) to 1.2 × 10(9) colony forming units per gram of substrate.

CONCLUSIONS

The study shows the isolation of some potential plant and human bacterial pathogens. However, most of the isolated species were either biocontrol species or saprophytes. The study questions the ways by which these bacterial species were introduced into potting media. To the best of our knowledge, this appears to be the first report of most of the isolated bacteria from potting media, except B. pumilus.

Phylogenetic relationship of phosphate solubilizing bacteria according to 16S rRNA genes

Phosphate solubilizing bacteria (PSB) can convert insoluble form of phosphorous to an available form. Applications of PSB as inoculants increase the phosphorus uptake by plant in the field. In this study, isolation and precise identification of PSB were carried out in Malaysian (Serdang) oil palm field (University Putra Malaysia). Identification and phylogenetic analysis of 8 better isolates were carried out by 16S rRNA gene sequencing in which as a result five isolates belong to the Beta subdivision of Proteobacteria, one isolate was related to the Gama subdivision of Proteobacteria, and two isolates were related to the Firmicutes. Bacterial isolates of 6upmr, 2upmr, 19upmnr, 10upmr, and 24upmr were identified as Alcaligenes faecalis. Also, bacterial isolates of 20upmnr and 17upmnr were identified as Bacillus cereus and Vagococcus carniphilus, respectively, and bacterial isolates of 31upmr were identified as Serratia plymuthica. Molecular identification and characterization of oil palm strains as the specific phosphate solubilizer can reduce the time and cost of producing effective inoculate (biofertilizer) in an oil palm field.

Seroprevalence of Triatoma virus (Dicistroviridae: Cripaviridae) antibodies in Chagas disease patients

BACKGROUND

Chagas disease is caused by Trypanosoma cruzi, and humans acquire the parasite by exposure to contaminated feces from hematophagous insect vectors known as triatomines. Triatoma virus (TrV) is the sole viral pathogen of triatomines, and is transmitted among insects through the fecal-oral route and, as it happens with T. cruzi, the infected insects release the virus when defecating during or after blood uptake.

METHODS

In this work, we analysed the occurrence of anti-TrV antibodies in human sera from Chagas disease endemic and non-endemic countries, and developed a mathematical model to estimate the transmission probability of TrV from insects to man, which ranged between 0.00053 and 0.0015.

RESULTS

Our results confirm that people with Chagas disease living in Bolivia, Argentina and Mexico have been exposed to TrV, and that TrV is unable to replicate in human hosts.

CONCLUSIONS

We presented the first experimental evidence of antibodies against TrV structural proteins in human sera.