Molecular Epidemiology of Nontuberculous Mycobacteria Isolates from Clinical and Environmental Sources of a Metropolitan City

Introduction

While NTM infection is mainly acquired from environmental exposure, monitoring of environmental niches for NTM is not a routine practice. This study aimed to find the prevalence of environmental NTM in soil and water in four highly populated suburbs of Tehran, Iran.

Material and Methods

A total of 4014 samples from soil and water resources were collected and studied. Sediments of each treated sample were cultured in Lowenstein-Jensen medium and observed twice per week for growth rate, colony morphology, and pigmentation. Colonies were studied with phenotypic tests. Molecular analysis was performed on single colonies derived from subculture of original isolates. Environmental samples were compared with 34 NTM isolates from patients who were residents of the study locations.

Results

Out of 4014 samples, mycobacteria were isolated from 862 (21.4%) specimens; 536 (62.1%) belonged to slow growing mycobacteria (SGM) and 326 (37.8%) were rapid growing mycobacteria (RGM). The five most frequent NTM were M. farcinogens (105/862; 12.1%), M. fortuitum (72/862; 8.3%), M. senegalense (58/862; 6.7%), M. kansasii (54/862; 6.2%), and M. simiae (46/862; 5.3%). In total, 62.5% (539/862) of mycobacterial positive samples were isolated from water and only 37.4% (323/862) of them were isolated from soil samples (P<0.05). Out of 5314 positive clinical samples for mycobacteria, 175 (3.2%) isolates were NTM. The trend of NTM isolates increased from 1.2% (13 out of 1078) in 2004 to 3.8% (39 out of 1005) in 2014 (P = 0.0001). The major clinical isolates were M. simiae (51; 29.1%), M. kansasii (26; 14.8%), M. chelonae (28; 16%), and M. fortuitum (13; 7.4%).

Conclusions

Comparing the distribution pattern of environmental NTM isolates with clinical isolates suggests a possible transmission link, but this does not apply to all environmental NTM species. Our study confirms an increasing trend of NTM isolation from clinical samples that needs further investigation.     

Evidence for widespread genomic methylation in the migratory locust, Locusta migratoria (Orthoptera: Acrididae)

The importance of DNA methylation in mammalian and plant systems is well established. In recent years there has been renewed interest in DNA methylation in insects. Accumulating evidence, both from mammals and insects, points towards an emerging role for DNA methylation in the regulation of phenotypic plasticity. The migratory locust (Locusta migratoria) is a model organism for the study of phenotypic plasticity. Despite this, there is little information available about the degree to which the genome is methylated in this species and genes encoding methylation machinery have not been previously identified. We therefore undertook an initial investigation to establish the presence of a functional DNA methylation system in L. migratoria. We found that the migratory locust possesses genes that putatively encode methylation machinery (DNA methyltransferases and a methyl-binding domain protein) and exhibits genomic methylation, some of which appears to be localised to repetitive regions of the genome. We have also identified a distinct group of genes within the L. migratoria genome that appear to have been historically methylated and show some possible functional differentiation. These results will facilitate more detailed research into the functional significance of DNA methylation in locusts.     

Human serum albumin–malathion complex study in the presence of silver nanoparticles at different sizes by multi spectroscopic techniques

The binding of malathion to human serum albumin (HSA) in the presence of silver nanoparticles (AgNPs) was investigated for the first time by multiple spectroscopic methods such as fluorescence quenching, fluorescence resonance energy transfer (FRET), circular dichroism, red-edge excitation shift (REES), synchronous fluorescence and three dimensional fluorescence spectroscopy under physiological conditions .The results indicated that binding of malathion to HSA induced fluorescence quenching through static mechanism. The number of binding sites was calculated by double logarithmic equation. Changes in the micro-environment of the fluorophore residues were also probed by synchronous fluorescence spectroscopy and REES. Changes of secondary structure of HSA in HSA–malathion complex was verified by circular dichroism approach in the presence of AgNPs that showed the electrostatic interaction changes in the protein structure. The binding average distance (r) between the donor (HSA) and the acceptor (malathion) was measured and found to be 1.63?nm according to the Forster’s theory of non-radiation energy transfer which was <7?nm confirmed the existence of static quenching in the presence of AgNPs. The conformational changes of HSA by three-dimensional fluorescence spectroscopy were studied. By comparing the resonance light scattering in the binary and ternary systems, we could estimate the effect of AgNPs on the precipitation of the malathion on the HSA. Generally we have discussed the toxicity reduction effect of malathion in food industrial by the results of spectroscopy techniques.     

In vivo antimutagenic effect of vitamins C and E against rifampicin-induced chromosome aberrations in mouse bone-marrow cells

-The genotoxic effect of rifampicin (RMP), one of the most active antituberculosis agents is studied. Also, the possible protection provided by the natural antioxidant vitamins C (VC) and E (VE) against the genotoxic effect of RMP is assessed.Mice were orally treated by gavage with 10, 50, 150 and 300 mg RMP kg(-1) body weight (bw). Also, oral treatment was conducted with RMP plus the vitamins. Mice received 300 mg RMP kg(-1) bw plus 100, 200 and 400mg VC or VE kg(-1) bw. Samples were taken 24h after the treatment. Repeated treatments with: (1) the therapeutic dose of RMP (10 mg kg(-1) bw); (2) RMP plus a dose of 25, 50 and 75 mg VC kg(-1); (3) RMP plus 10, 20 and 40 mg VE kg(-1) bw for 30 consecutive days were conducted.The tested doses of RMP induced a significant increase in the percentage of chromosome aberrations. However, a lower percentage of chromosome aberrations was observed when animals were treated with the therapeutic dose for 30 consecutive days.The obtained results revealed that chromosome aberrations induced by RMP decreased to a significant extent when mice were treated with RMP plus VC. The repeated doses of VC reduced the percentage of chromosome aberrations induced by RMP in a significant and dose-dependent manner. On the other hand, repeated doses of VE were not very effective in reducing the percentage of chromosome aberrations induced by RMP. Only the highest dose (3 x 40 mg kg(-1) bw) showed a significant effect (P<0.01).The results on the induction of chromosome damage clearly show that only VC appears able to efficiently protect the bone-marrow cells when given together with RMP, while no significant reduction in the yield of chromosome aberrations was observed for VE in combination with the antituberculosis drug.     

Adoption and Children with Learning and Behavior Problems

One representative case study is used to illustrate the complex interaction of factors that can lead to tragic family dysfunction when an adopted child has learning and behavior problems. The presence of neurodevelopmental problems in an adopted child, special adoption issues and interparental and intraparental conflicts combine to place the child and his family at high risk. The child''s neurodevelopmental difficulties are expressed primarily as subtle learning and behavior problems which make him a focus for parental conflict. In addition, the adoption issues of difference, impermanence, feelings of mutual obligation and fear of abandonment are generally poorly understood and form the basis for the development of unique interactional patterns of communication. Finally, in the families studied, it was often found that the adopting parents had serious personal and/or marital difficulties.     

An ecdysone receptor from the pentatomomorphan, Nezara viridula, shows similar affinities for moulting hormones makisterone A and 20-hydroxyecdysone

It has been suggested that Pentatomomorpha utilise the C₂₈ ecdysteroid, makisterone A (MakA), as the major moulting hormone rather than the more common C₂₇ hormone, 20-hydroxyecdsyone (20E). The present study is the first to examine this postulate at the level of the ecdysone receptor protein, a heterodimer of nuclear receptors EcR and USP. cDNAs encoding two alternatively spliced isoforms of EcR and a single USP were isolated from a high-quality cDNA library prepared from a representative pentatomomorphan, Nezara viridula (Nv). NvEcR and NvUSP were found to group phylogenetically with heteropteran and other insect EcRs and USP/RXRs, respectively. Sequence comparison and phylogenetic analysis of these proteins found them to be distinct from those belonging to other hemipteran ecdysone receptors characterised to date. Co-expression of the His₆-tagged ligand binding regions (LBRs) of the two NvEcR variants with the FLAG-tagged LBR of NvUSP was achieved in insect cells employing appropriately constructed baculoviruses. The corresponding heterodimers, designated NvE10 and NvE11, were purified by affinity chromatography utilising the His₆ tags on their NvEcR subunits. The heterodimers displayed nanomolar affinity for [³H]ponasterone A (K_d = 6.8-7.5 nM), characteristic of ecdysone receptors. MakA has a similar affinity to 20E for both NvE10 and NvE11, consistent with MakA being a major moulting hormone in N. viridula.     

Necroptosis and RhoA/ROCK pathways: molecular targets of Nesfatin-1 in cardioprotection against myocardial ischemia/reperfusion injury in a rat model

Molecular Biology Reports - Nesfatin-1 as a new energy-regulating peptide has been known to display a pivotal role in modulation of cardiovascular functions and protection against...