DNA damage induction and antiproliferative activity of vanadium(V) oxido monoperoxido complex containing two bidentate heteroligands

Several peroxidovanadium(V) complexes have been shown as a potent anticancer agents. The aim of this study was to investigate the interaction of monoperoxidovanadium(V) complex Pr₄N[VO(O₂)(ox)(phen)], (Vphen), [phen = 1,10-phenantroline, ox = oxalate(2?) and Pr₄N = tetra(n-propyl)ammonium(1+)] with DNA. UV–Vis spectrophotometry and the alkaline single-cell gel electrophoresis (SCGE, the comet assay) were used to examine the possibility of the vanadium(V) complex to induce changes in DNA. The interaction of Vphen with calf thymus DNA resulted in absorption hyperchromicity in DNA spectrum and shift of the absorption band of DNA to longer wavelengths for the [complex]/[DNA] concentration ratio equals to 4 and after 60 min of incubation. The rise in DNA absorption (by 34%) and bathochromic shift (Δλ_max = 6 nm) are indicative of the interaction between DNA and the complex molecules. DNA strand breaks in cellular DNA were investigated using the comet assay. The human lymphocytes were exposed to various concentrations of Vphen for 30 min. The results revealed that Vphen contributed to the DNA damage expressed as DNA strand breaks in concentration dependent manner. The used concentrations of Vphen (ranging from 0.1 to 100 μmol/L) caused higher DNA damage in lymphocytes compared to untreated cells (from 1.2 times for 0.1 μmol/L to 1.8 times for 100 μmol/L). Vphen was screened for its potential antitumor activity towards murine leukemia cell line L1210. Vphen exhibited significant antiproliferative activity depending on its concentration and time of exposure. The IC₅₀ values were 0.247 μg/mL (0.45 μmol/L) for 24 h, 0.671 μg/mL (1.21 μmol/L) for 48 h and 0.627 μg/mL (1.13 μmol/L) for 72 h.     

Phenol degradation by halophilic bacteria isolated from hypersaline environments

Phenol is a toxic aromatic compound used or produced in many industries and as a result a common component of industrial wastewaters. Phenol containing waste streams are frequently hypersaline and therefore require halophilic microorganisms for efficient biotreatment without dilution. In this study three halophilic bacteria isolated from different saline environments and identified as Halomonas organivorans, Arhodomonas aquaeolei and Modicisalibacter tunisiensis were shown to be able to grow on phenol in hypersaline media containing 100 g/L of total salts at a concentration of 3 mM (280 mg/L), well above the concentration found in most waste streams. Genes encoding the aromatic dioxygenase enzymes catechol 1,2 dioxygenase and protocatechuate 3,4-dioxygenase were present in all strains as determined by PCR amplification using primers specific for highly conserved regions of the genes. The gene for protocatechuate 3,4-dioxygenase was cloned from the isolated H. organivorans and the translated protein was evaluated by comparative protein sequence analysis with protocatechuate 3,4-dioxygenase proteins from other microorganisms. Although the analysis revealed a wide range of sequence divergence among the protocatechuate 3,4-dioxygenase family, all of the conserved domain amino acid structures identified for this enzyme family are identical or conservatively substituted in the H. organivorans enzyme.     

Aerobic biodegradation of propylene glycol by soil bacteria

Propylene glycol (PG) is a main component of aircraft deicing fluids and its extensive use in Northern airports is a source of soil and groundwater contamination. Bacterial consortia able to grow on PG as sole carbon and energy source were selected from soil samples taken along the runways of Oslo Airport Gardermoen site (Norway). DGGE analysis of enrichment cultures showed that PG-degrading populations were mainly composed by Pseudomonas species, although Bacteroidetes were found, as well. Nineteen bacterial strains, able to grow on PG as sole carbon and energy source, were isolated and identified as different Pseudomonas species. Maximum specific growth rate of mixed cultures in the absence of nutrient limitation was 0.014 h^?1 at 4 °C. Substrate C:N:P molar ratios calculated on the basis of measured growth yields are in good agreement with the suggested values for biostimulation reported in literature. Therefore, the addition of nutrients is suggested as a suitable technique to sustain PG aerobic degradation at the maximum rate by autochthonous microorganisms of unsaturated soil profile.     

Identification of the infectious source of an unusual outbreak of histoplasmosis,in a hotel in Acapulco,state of Guerrero,Mexico

Three isolates of Histoplasma capsulatum were identified from mice lung, liver, and spleen inoculated with soil samples of the X hotel’s ornamental potted plants that had been fertilized with organic material known as compost. The presence of H. capsulatum in the original compost was detected using the dot-enzyme-linked immunosorbent assay. Nested-PCR, using a specific protein Hcp100 coding gene sequence, confirmed the fungal identification associated with an unusual histoplasmosis outbreak in Acapulco. Although, diversity between the H. capsulatum isolate from the hotel and some clinical isolates from Guerrero (positive controls) was observed using random amplification of polymorphic DNA based-PCR, sequence analyses of H-anti and ole fragment genes revealed a high homology (92–99%) between them.     

IFN-α Regulates Blimp-1 Expression via miR-23a and miR-125b in Both Monocytes-Derived DC and pDC

Type I interferon (IFN-I) have emerged as crucial mediators of cellular signals controlling DC differentiation and function. Human DC differentiated from monocytes in the presence of IFN-α (IFN-α DC) show a partially mature phenotype and a special capability of stimulating CD4+ T cell and cross-priming CD8+ T cells. Likewise, plasmacytoid DC (pDC) are blood DC highly specialized in the production of IFN-α in response to viruses and other danger signals, whose functional features may be shaped by IFN-I. Here, we investigated the molecular mechanisms stimulated by IFN-α in driving human monocyte-derived DC differentiation and performed parallel studies on peripheral unstimulated and IFN-α-treated pDC. A specific miRNA signature was induced in IFN-α DC and selected miRNAs, among which miR-23a and miR-125b, proved to be negatively associated with up-modulation of Blimp-1 occurring during IFN-α-driven DC differentiation. Of note, monocyte-derived IFN-α DC and in vitro IFN-α-treated pDC shared a restricted pattern of miRNAs regulating Blimp-1 expression as well as some similar phenotypic, molecular and functional hallmarks, supporting the existence of a potential relationship between these DC populations. On the whole, these data uncover a new role of Blimp-1 in human DC differentiation driven by IFN-α and identify Blimp-1 as an IFN-α-mediated key regulator potentially accounting for shared functional features between IFN-α DC and pDC.     

Multiple myeloma and occupation: A pooled analysis by the International Multiple Myeloma Consortium

Objective: We investigated occupational risk of multiple myeloma (MM) in a pooled analysis of five international case–control studies. Methods: We calculated the odds ratio and its 95% confidence interval for selected occupations with unconditional regression analysis in 1959 MM cases and 6192 controls, by pooling study-specific risks using random-effects meta-analysis. Exposure to organic solvents was assessed with a job-exposure matrix (JEM). Results: Gardeners and nursery workers combined, most likely exposed to pesticides, showed a 50% increase in risk (OR = 1.50, 95% CI 0.9–2.3), while other farming jobs did not. Metal processors (OR = 1.55, 95% CI 0.9–2.3), female cleaners (OR = 1.32, 95% CI 1.0–1.8), and high level exposure to organic solvents (OR = 1.38, 95% CI 0.96–1.8) also showed moderately increased risks. Conclusions: Additional case–control studies of MM aetiology are warranted to further investigate the nature of the repeatedly reported increase in MM risk in several occupational groups.     

Distribution Dynamics of Recombinant Lactobacillus in the Gastrointestinal Tract of Neonatal Rats

One approach to deliver therapeutic agents, especially proteins, to the gastro-intestinal (GI) tract is to use commensal bacteria as a carrier. Genus Lactobacillus is an attractive candidate for use in this approach. However, a system for expressing exogenous proteins at a high level has been lacking in Lactobacillus. Moreover, it will be necessary to introduce the recombinant Lactobacillus into the GI tract, ideally by oral administration. Whether orally administered Lactobacillus can reach and reside in the GI tract has not been explored in neonates. In this study, we have examined these issues in neonatal rats. To achieve a high level of protein expression in Lactobacillus, we tested the impact of three promoters and two backbones on protein expression levels using mRFP1, a red fluorescent protein, as a reporter. We found that a combination of an L-lactate dehydrogenase (ldhL) promoter of Lactobacillus sakei with a backbone from pLEM415 yielded the highest level of reporter expression. When this construct was used to transform Lactobacillus casei, Lactobacillus delbrueckii and Lactobacillus acidophilus, high levels of mRFP1 were detected in all these species and colonies of transformed Lactobacillus appeared pink under visible light. To test whether orally administered Lactobacillus can be retained in the GI tract of neonates, we fed the recombinant Lactobacillus casei to neonatal rats. We found that about 3% of the bacteria were retained in the GI tract of the rats at 24 h after oral feeding with more recombinant Lactobacillus in the stomach and small intestine than in the cecum and colon. No mortality was observed throughout this study with Lactobacillus. In contrast, all neonatal rats died within 24 hours after fed with transformed E. coli. Taken together, our results indicate that Lactobacillus has the potential to be used as a vehicle for the delivery of therapeutic agents to neonates.     

The rpb2 gene represents a viable alternative molecular marker for the analysis of environmental fungal communities

Although the commonly used internal transcribed spacer region of rDNA (ITS) is well suited for taxonomic identification of fungi, the information on the relative abundance of taxa and diversity is negatively affected by the multicopy nature of rDNA and the existence of ITS paralogues. Moreover, due to high variability, ITS sequences cannot be used for phylogenetic analyses of unrelated taxa. The part of single‐copy gene encoding the second largest subunit of RNA polymerase II (rpb2) was thus compared with first spacer of ITS as an alternative marker for the analysis of fungal communities in spruce forest topsoil, and their applicability was tested on a comprehensive mock community. In soil, rpb2 exhibited broad taxonomic coverage of the entire fungal tree of life including basal fungal lineages. The gene exhibited sufficient variation for the use in phylogenetic analyses and taxonomic assignments, although it amplifies also paralogues. The fungal taxon spectra obtained with rbp2 region and ITS1 corresponded, but sequence abundance differed widely, especially in the basal lineages. The proportions of OTU counts and read counts of major fungal groups were close to the reality when rpb2 was used as a molecular marker while they were strongly biased towards the Basidiomycota when using the ITS primers ITS1/ITS4. Although the taxonomic placement of rbp2 sequences is currently more difficult than that of the ITS sequences, its discriminative power, quantitative representation of community composition and suitability for phylogenetic analyses represent significant advantages.     

Landscape genetics of a tropical rescue pollinator

Pollination services are increasingly threatened by the loss and modification of natural habitats, posing a risk to the maintenance of both native plant biodiversity and agricultural production. In order to safeguard pollination services, it is essential to examine the impacts of habitat degradation on the population dynamics of key pollinators and identify potential “rescue pollinators” capable of persisting in these human-altered landscapes. Using a landscape genetic approach, we assessed the impact of landscape structure on genetic differentiation in the widely-distributed tropical stingless bee Trigona spinipes (Apidae: Meliponini) across agricultural landscape mosaics composed of coffee plantations and Atlantic forest fragments in southeastern Brazil. We genotyped 115 bees at 16 specific and highly polymorphic microsatellite loci, developed using next-generation sequencing. Our results reveal that T. spinipes is capable of dispersing across remarkably long distances, as we did not find genetic differentiation across a 200 km range, nor fine-scale spatial genetic structure. Furthermore, gene flow was not affected by forest cover, land cover, or elevation, indicating that reproductive individuals are able to disperse well through agricultural landscapes and across altitudinal gradients. We also found evidence of a recent population expansion, suggesting that this opportunistic stingless bee is capable of colonizing degraded habitats. Our results thus suggest that T. spinipes can persist in heavily-altered landscapes and can be regarded as a rescue pollinator, potentially compensating for the decline of other native pollinators in degraded tropical landscapes.