Metal Contents in Feathers from Birds (Rhynchopsitta terrisi, and Columba livia) with Different Ecological Niches.

The metal contaminants can be utilized as an ecological tool to analyze niche partition in birds. As environmental contamination biological indicators, essential (Zn, Cu, and Cr) and non-essential (Pb and Cd) metals in the flight feathers of the Maroon-fronted Parrot and Pigeon with different ecological niches were assessed. The feathers of the parrot were gathered at a national park (Parque Nacional Cumbres de Monterrey) and the feathers of pigeons were collected at an urban site, that is, the city of Monterrey, Mexico. An atomic absorption spectrophotometer was used to establish the concentration of metals in the feathers. Zn, Cu, Cr, Pb, and Cd were detected in the two studied samples. The results obtained in this study exhibited an increase in metal concentrations in pigeon feathers with respect to parrot feathers. In conclusion, employing parrot and pigeon feathers comprises an important tool to track trace-metal occurrence in the environment and metal accumulation in birds. This information is crucial to possess in order to minimize exposure to essential metals in species of wild birds with different ecological niches.

Mycobacterium tuberculosis promotes genomic instability in macrophages.

BACKGROUND: Mycobacterium tuberculosis is an intracellular pathogen, which may either block cellular defensive mechanisms and survive inside the host cell or induce cell death. Several studies are still exploring the mechanisms involved in these processes. OBJECTIVES: To evaluate the genomic instability of M. tuberculosis-infected macrophages and compare it with that of uninfected macrophages. METHODS: We analysed the possible variations in the genomic instability of Mycobacterium-infected macrophages using the DNA breakage detection fluorescence in situ hybridisation (DBD-FISH) technique with a whole human genome DNA probe. FINDINGS: Quantitative image analyses showed a significant increase in DNA damage in infected macrophages as compared with uninfected cells. DNA breaks were localised in nuclear membrane blebs, as confirmed with DNA fragmentation assay. Furthermore, a significant increase in micronuclei and nuclear abnormalities were observed in infected macrophages versus uninfected cells. MAIN CONCLUSIONS: Genomic instability occurs during mycobacterial infection and these data may be seminal for future research on host cell DNA damage in M. tuberculosis infection.

Flourensia cernua: Hexane Extracts a Very Active Mycobactericidal Fraction from an Inactive Leaf Decoction against Pansensitive and Panresistant Mycobacterium tuberculosis.

The efficacy of decoction in extracting mycobactericidal compounds from Flourensia cernua (Hojasé) leaves and fractionation with solvents having ascending polarity was compared with that of (i) ethanol extraction by still maceration, extraction with a Soxhlet device, shake-assisted maceration, or ultrasound-assisted maceration, followed by fractionation with n-hexane, ethyl acetate, and n-butanol; (ii) sequential extraction with n-hexane, ethyl acetate, and n-butanol, by still maceration, using a Soxhlet device, shake-assisted maceration, or ultrasound-assisted maceration. The in vitro mycobactericidal activity of each preparation was measured against drug-sensitive (SMtb) and drug-resistant (RMtb) Mycobacterium tuberculosis strains. The results of which were expressed as absolute mycobactericidal activity (AMA). These data were normalized to the ΣAMA of the decoction fraction set. Although decoction was inactive, the anti-RMtb normalized ΣAMA (NAMA) of its fractions was comparable with the anti-RMtb NAMA of the still maceration extracts and significantly higher than the anti-SMtb and anti-RMtb NAMAs of every other ethanol extract and serial extract and fraction. Hexane extracted, from decoction, material having 55.17% and 92.62% of antituberculosis activity against SMtb and RMtb, respectively. Although the mycobactericidal activity of decoction is undetectable; its efficacy in extracting F. cernua active metabolites against M. tuberculosis is substantially greater than almost all pharmacognostic methods.

Efficacious In Vitro and In Vivo Effects of Dihydrosphingosine-Ethambutol Analogues Against Susceptible and Multi-drug-resistant Mycobacterium tuberculosis.

BACKGROUND AND AIMS: Tuberculosis (TB) is a major worldwide health problem in part due to the lack of new drugs and the emergence of multidrug-resistant strains (MDR). The aim of this study was to select anti-tuberculosis drug candidates from a collection of 69 synthetic sphingosine-ethambutol analogues through in vitro and in vivo evaluations. METHODS: The 69 compounds were evaluated in vitro against two Mycobacterium tuberculosis strains, a drug susceptible (H37Rv) and a MDR clinical isolate (CIBIN-99). Four selected compounds, those that exhibited the highest potency in vitro, were tested in vivo using a model of progressive TB in BALB/c mice infected with the drug susceptible strain, either alone or combined with conventional chemotherapy, as well as in mice infected with the MDR strain. The acute toxicity was evaluated on male and female adult BALB/c mice. RESULTS: Ten of the evaluated compounds resulted more potent in vitro than ethambutol. The experimental compound 2b (2-aminopalmitol benzyl ether) was the most efficacious and also showed additive effects in combination with conventional chemotherapy. It did not exhibit toxicity (LD50 >2000 mg/kg). CONCLUSIONS: Compound 2b can be considered as a new drug candidate to continue its development against M. tuberculosis MDR strains.

Mycobacterium tuberculosis promotes genomic instability in macrophages

BACKGROUND Mycobacterium tuberculosis is an intracellular pathogen, which may either block cellular defensive mechanisms and survive inside the host cell or induce cell death. Several studies are still exploring the mechanisms involved in these processes. OBJECTIVES To evaluate the genomic instability of M. tuberculosis-infected macrophages and compare it with that of uninfected macrophages. METHODS We analysed the possible variations in the genomic instability of Mycobacterium-infected macrophages using the DNA breakage detection fluorescence in situ hybridisation (DBD-FISH) technique with a whole human genome DNA probe. FINDINGS Quantitative image analyses showed a significant increase in DNA damage in infected macrophages as compared with uninfected cells. DNA breaks were localised in nuclear membrane blebs, as confirmed with DNA fragmentation assay. Furthermore, a significant increase in micronuclei and nuclear abnormalities were observed in infected macrophages versus uninfected cells. MAIN CONCLUSIONS Genomic instability occurs during mycobacterial infection and these data may be seminal for future research on host cell DNA damage in M. tuberculosis infection.

Arsenic induces DNA damage in environmentally exposed Mexican children and adults. Influence of GSTO1 and AS3MT polymorphisms.

Inorganic arsenic (i-As) is an environmental carcinogen to which millions of people are chronically exposed mainly via drinking water. In this study, we used the comet assay to evaluate DNA damage in i-As-exposed inhabitants of the north of Mexico. The environmental monitoring and the exposure assessment were done by measuring both drinking water arsenic (As) content and total urinary As. In addition, the studied population was genetically characterized for four different glutathione S-transferase omega1 (GSTO1) polymorphisms (Ala140Asp, Glu155del, Glu208Lys, and Ala236Val) and the As (+3 oxidation state) methyltransferase (AS3MT) Met287Thr polymorphism to determine whether such variants influence As-related genotoxicity. As content in the drinking water of the population was found to range between 1 and 187 microg/l, with a mean concentration value of 16 microg/l. The total urinary As content of the exposed individuals was found to be correlated with the As content in drinking water, and subjects were classified as low (< 30 microg As/g creatinine), medium (31-60 microg As/g creatinine), and highly exposed (> 61 microg As/g creatinine). A positive association was found between the level of exposure and the genetic damage measured as percentage of DNA in tail (p < 0.001), and AS3MT Met287Thr was found to significantly influence the effect (p < 0.034) among children carrying the 287Thr variant allele. Altogether, our results evidenced that people living in As-contaminated areas are at risk and that AS3MT genetic variation may play an important role modulating such risk in northern Mexico, especially among children.