Molecular characterization of rhizospheric soil streptomycetes isolated from indigenous Turkish plants and their antimicrobial activity

As part of a research program whose aim is to determine the diversity of streptomycetes in order to discover new bioactive secondary metabolites, rhizosphere soils of three indigenous plants were analyzed. A total of 55 actinomycetes were isolated using three different medium from the samples. The rhizospheric soil of the plant Aethionema dumanii gave the highest number of actinomycetes, i.e., 42% versus 27% and 31% for the soils from Salvia aytachii and Achillea ketenoglui, respectively. The AIA is the most favorable medium for the isolation of the actinomycetes from different rhizospheric soils. 16S rDNA sequence analysis revealed that while some isolates belong to different cluster groups such as Streptomyces lydicus, S. rochei, S. microflavus, S. griseoflavus, S. albidoflavus and S. violaceusniger, the majority of the sequences did not considerable clustered with the member of different Streptomyces groups. The in vitro antimicrobial activities of the crude organic and aqueous extracts of isolates were screened using a disc diffusion assay against a panel of bacteria and C. albicans. A total of 22 isolates showed antimicrobial activity. The antibacterial action of the extracts is more pronounced on Gram-positive than on Gram-negative bacteria in most cases. About 18% of the actinomycetes showed also antifungal activity. Study of the influence of two different culture media on production of bioactive molecules showed that the higher antimicrobial activity was obtained in M2 when compared to TSB. The results from this study provide evidence that the streptomycetes in the rhizosphere soils could be promising sources for antimicrobial bioactive agents.     

Anaerobic treatment of a chemical synthesis-based pharmaceutical wastewater in a hybrid upflow anaerobic sludge blanket reactor

In this study, performance of a lab-scale hybrid up-flow anaerobic sludge blanket (UASB) reactor, treating a chemical synthesis-based pharmaceutical wastewater, was evaluated under different operating conditions. This study consisted of two experimental stages: first, acclimation to the pharmaceutical wastewater and second, determination of maximum loading capacity of the hybrid UASB reactor. Initially, the carbon source in the reactor feed came entirely from glucose, applied at an organic loading rate (OLR) 1 kg COD/m(3) d. The OLR was gradually step increased to 3 kg COD/m(3) d at which point the feed to the hybrid UASB reactor was progressively modified by introducing the pharmaceutical wastewater in blends with glucose, so that the wastewater contributed approximately 10%, 30%, 70%, and ultimately, 100% of the carbon (COD) to be treated. At the acclimation OLR of 3 kg COD/m(3) d the hydraulic retention time (HRT) was 2 days. During this period of feed modification, the COD removal efficiencies of the anaerobic reactor were 99%, 96%, 91% and 85%, and specific methanogenic activities (SMA) were measured as 240, 230, 205 and 231 ml CH(4)/g TVS d, respectively. Following the acclimation period, the hybrid UASB reactor was fed with 100% (w/v) pharmaceutical wastewater up to an OLR of 9 kg COD/m(3) d in order to determine the maximum loading capacity achievable before reactor failure. At this OLR, the COD removal efficiency was 28%, and the SMA was measured as 170 ml CH(4)/g TVS d. The hybrid UASB reactor was found to be far more effective at an OLR of 8 kg COD/m(3) d with a COD removal efficiency of 72%. At this point, SMA value was 200 ml CH(4)/g TVS d. It was concluded that the hybrid UASB reactor could be a suitable alternative for the treatment of chemical synthesis-based pharmaceutical wastewater.     

MitraClip step by step; how to simplify the procedure

The MitraClip system is a device for percutaneous edge-to-edge reconstruction of the mitral valve in patients with severe mitral regurgitation who are deemed at high risk for surgery. Studies have underlined the therapeutic benefit of the MitraClip system for patients at extreme and high risk for mitral valve surgery, suffering from either degenerative or functional mitral regurgitation. The MitraClip procedure shows low peri-procedural complication rates, and a significant reduction in mitral regurgitation, as well as an improvement in functional capacity and most importantly quality of life. It hereby widens the spectrum of mitral valve repair for the Heart Team. The current review underscores the efficacy of the procedure and describes the technique to simplify the procedure.     

Assessment of the horizontal transfer of functional genes as a suitable approach for evaluation of the bioremediation potential of petroleum-contaminated sites: a mini-review

Petroleum sludge contains recalcitrant residuals. These compounds because of being toxic to humans and other organism are of the major concerns. Therefore, petroleum sludge should be safely disposed. Physicochemical methods which are used by this sector are mostly expensive and need complex devices. Bioremediation methods because of being eco-friendly and cost-effective overcome most of the limitations of physicochemical treatments. Microbial strains capable to degrade petroleum hydrocarbons are practically present in all soils and sediments and their population density increases in contact with contaminants. Bacterial strains cannot degrade alone all kinds of petroleum hydrocarbons, rather microbial consortium should collaborate with each other for degradation of petroleum hydrocarbon mixtures. Horizontal transfer of functional genes between bacteria plays an important role in increasing the metabolic potential of the microbial community. Therefore, selecting a suitable degrading gene and tracking its horizontal transfer would be a useful approach to evaluate the bioremediation process and to assess the bioremediation potential of contaminated sites.     

Restoration of the eutrophic Lake Eymir, Turkey, by biomanipulation after a major external nutrient control I

Nutrient loading in lakes is recognized as a serious threat to water quality. Over 25 years of raw sewage effluent discharge shifted Lake Eymir from a state dominated by submerged plants to a turbid water state. Successful effluent diversion undertaken in 1995 achieved 88% and 95% reductions in the areal loading of total phosphorus (TP) and dissolved inorganic nitrogen (DIN), respectively. Furthermore, the reduced load of TP was very close to the suggested threshold areal load (0.6 g m^–2 yr^–1) to attain recovery. Even though diversion also reduced the in-lake TP level by half, the poor water clarity and low submerged plant coverage (112 ± 43 cm and 2.5% coverage of the lake total surface area, respectively) persisted. Domination of the fish stock by planktivorous tench (Tinca tinca L.) and the benthivorous common carp (Cyprinus carpio L.) (66 ± 0.7 and 31 ± 1 kg CPUE, respectively) appeared to perpetuate the poor water condition. A substantial fish removal effort over 1 year achieved a 57% reduction in the fish stock which led to a 2.5-fold increase in Secchi disk transparency. This increase occurred largely because of a 4.5-fold decrease in the inorganic suspended solid concentration, and to some extent, a decrease in chlorophyll-a concentration. A strong top-down effect of fish on the large-sized grazers was evident as density and the body size of Daphnia pulexde Geer increased significantly after the fish removal. Even though the spring and annual euphotic depths occurred well above the maximum and mean depths of the lake, respectively, re-development of submerged plants was poor (6.2% coverage). A weak re-establishment of submerged plants might be attributed to an insufficiently viable seed bank, inappropriate chemical conditions of the sediment (severe oxygen deficiency), or to the high coot (Fulica atra L.) density. However, the top-down effect of fish appeared to be of great importance in determining water clarity, and in turn, conditions for submerged plant development in a warm temperate lake as recorded in the north temperate lakes. Furthermore, this study provides evidence for the importance of top-down control of fish, which, in turn, can be effectively utilised as a restoration strategy in warm-temperate lakes as well. More applications, along with long monitoring programs, are needed to develop a better understanding about requirements for biomanipulation success in this climate.     

Reduction to homozygosity at the SIS/PDGF-2 locus in human mesenchymal tumors

Enhanced expression of the human SIS/PDGF-2 gene has been reported in a number of human cell lines, sarcomas, and glioblastomas. We have analyzed the SIS/PDGF-2 gene for structural alterations in fresh human tumors. DNA samples from 79 patients with solid tumors (63 mesenchymal tumors, 12 lung carcinomas, 4 breast carcinomas) were examined and compared with DNA samples from 50 leukemia patients and 14 unrelated individuals without malignant neoplasms. When DNA samples were digested with a HindIII restriction endonuclease, Southern blot analysis demonstrated two distinct bands (21kb and 18kb) after hybridization to the SIS/PDGF-2 gene probe. A pedigree analysis of a 43-member family indicated that these allelic variants segregated in a Mendelian fashion. There was, however, tumor specific allele loss in 18% of the mesenchymal tumors analyzed, which may indicate a common etiology for this tumor type.     

Oxidative Damage to Proteins, Lipids, and DNA in Cortical Brain Regions from Patients with Dementia with Lewy Bodies

Abstract: Dementia with Lewy bodies (DLB) forms the second most common pathological subgroup of dementia after Alzheimer's disease. The present study compares the levels of oxidative damage to proteins, lipids, and DNA bases in cortical brain areas from patients with DLB with levels in matched control tissues. Overall, there was a trend for protein carbonyl levels to be increased in all areas, but a significant difference was found only in the parietal and temporal lobes. No differences were observed in the levels of lipid peroxidation. Measurement of products of damage to DNA bases showed increased levels of thymine glycol, 8-hydroxyguanine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 5-hydroxycytosine, 5-hydroxyuracil, 5-hydroxymethyluracil, and xanthine. Xanthine levels were increased in the DLB group in the parietal, occipital, and temporal lobes, indicating that peroxynitrite or other deaminating species may be involved. The finding of increased protein carbonyls and increased DNA base products in cortical regions from DLB patients indicates that oxidative stress may play a role in DLB.