Slime production and proteinase activity of Candida species isolated from blood samples and the comparison of these activities with minimum inhibitory concentration values of antifungal agents

Slime and proteinase activity of 54 strains consisting of 19 Candida parapsilosis and 35 C. albicans strains isolated from blood samples were investigated in this study. Ketoconazole, amphothericin B, and fluconazole susceptibility of Candida species were compared with slime production and proteinase activity of these species. For both Candida species, no correlation was detected between the slime activity and minimum inhibitory concentration (MIC) values of the three antifungal agents. For both Candida species no correlation was detected between the proteinase activity and the MIC values of amphothericin B, and fluconazole however, statistically significant difference, was determined between the proteinase activity and MIC values of ketoconazole (p = 0.007). Slime production was determined by using modified Christensen macrotube method and proteinase activity was measured by the method of Staib. Antifungal susceptibility was determined through the guidelines of National Committee for Laboratory Standards (NCCLS M27-A).     

Clarithromycin resistance prevalence and Icea gene status in Helicobacter Pylori clinical isolates in Turkish patients with duodenal ulcer and functional dyspepsia

Clarithromycin resistance in Helicobacter pylori is a principal cause of failure of eradication therapies, and its prevalence varies geographically. The IceA gene is a virulence factor associated with clinical outcomes. The objective of this study was to determine the current state of clarithromycin resistance prevalence, and to investigate the role of iceA genotypes in 87 Turkish adult patients (65 with functional dyspepsia and 22 with duodenal ulcer). A2143G and A2144G point mutations were tested by PCR-RFLP for clarithromycin resistance. Among the patients in the study, 28 patients were tested by agar dilution as well. Allelic variants of the iceA gene were identified by PCR. A total of 24 (27.6%) strains evidenced one of the mutations, either A2143G or A2144G. IceA1 was found to be positive in 28 of the strains (32.2%), iceA2 was positive in 12 (13.8%) and, both iceA1 and iceA2 were positive in 22 (25.3%) strains. In conclusion, we discovered no relationships between iceA genotypes and functional dyspepsia or duodenal ulcer, nor between clarithromycin resistance and iceA genotypes. Clarithromycin resistance appears to be more prevalent in Turkish patients.     

Access to new highly potent antileukemia,antiviral and antimalarial agents via hybridization of natural products (homo)egonol,thymoquinone and artemisinin

Hybridization of natural products has high potential to further improve their activities and may produce synergistic effects between linked pharmacophores. Here we report synthesis of nine new hybrids of natural products egonol, homoegonol, thymoquinone and artemisinin and evaluation of their activities against P. falciparum 3D7 parasites, human cytomegalovirus, sensitive and multidrug-resistant human leukemia cells. Most of the new hybrids exceed their parent compounds in antimalarial, antiviral and antileukemia activities and in some cases show higher in vitro efficacy than clinically used reference drugs chloroquine, ganciclovir and doxorubicin. Combined, our findings stress the high potency of these hybrids and encourages further use of the hybridization concept in applied pharmacological research.     

Cardiopulmonary bypass as a cause of free radical-induced oxidative stress and enhanced blood-borne isoprostanes in humans

Free radicals are believed to be involved in postsurgery-related complications. We studied whether cardiopulmonary bypass (CPB) operation has any immediate impact on the initiation of oxidative stress and inflammatory response by measuring isoprostanes and prostaglandin F2alpha during and 24 h following CPB. The levels of 8-iso-PGF2alpha (a major F2-isoprostane and biomarker of oxidative stress) and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha and biomarker of inflammatory response) were measured in frequently collected plasma samples before, during, and up to 24 h postsurgery in 21 patients. 8-Iso-PGF2alpha levels significantly increased within 3 min (p <.0001) and continued until 50 min (p <.0001) during CPB. On the contrary, no significant increase of inflammatory response indicator, 15-keto-dihydro-PGF2alpha was found during and up to 24 h postoperatively. These findings establish an increased free radical-induced oxidative stress activity rather than inflammatory response after CPB.     

One-pot conjugated linoleic acid production from castor oil by Rhizopus oryzae lipase and resting cells of Lactobacillus plantarum

Conjugated linoleic acid (CLA) has attracted as novel type of fatty acids having unusual health-promoting properties such as anticarcinogenic and antiobesitic effects. The present work employed castor oil as substrate for one-pot production of CLA using washed cells of Lactobacillus plantarum (L. plantarum) and lipases as catalysts. Among the screened lipases, the lipase Rhizopus oryzae (ROL) greatly assisted resting cells to produce CLA. Mass spectral analysis of the product showed that two major isomers of CLA were produced in the reaction mixture i.e. cis-9, trans-11 56.55% and trans-10, cis-12 43.45%. Optimum factors for CLA synthesis were found as substrate concentration (8 mg/mL), pH (6.5), washed cell concentration (12% w/v), and incubation time of 20 h. Hence, the combination of ROL with L. plantarum offers one pot production of CLA selectively using castor oil as a cost-effective substrate.     

Encapsulation of Pt-labelled DNA Molecules inside Carbon Nanotubes

Experiments on encapsulating Pt--labelled DNA molecules inside multiwalled carbon nanotubes (MWCNT) were performed under temperature and pressure conditions of 400K and 3 Bar. The DNA-CNT hybrids were purified via agarose gel electrophoresis and analyzed via high resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray spectroscopy (EDX). The results showed that the Pt-labelled DNA molecules attached to the outside walls of CNTs could be removed by electrophoresis. The HR-TEM and EDX results demonstrated that 2-3% of the Pt-labelled DNA molecules were successfully encapsulated inside the MWCNTs. The experimental study complements our previous molecular dynamics simulations on encapsulation of single stranded DNA oligonucleotides inside single wall carbon nanotubes under similar conditions in water. The van der Waals interaction between CNT and Pt-labelled DNA is believed to be the main driving force for this phenomenon. The DNA-CNT molecular complex could be further explored for potential applications in bio-nanotechnology.     

Effects of some boron compounds on peripheral human blood

Peripheral blood cultures were exposed to various doses (5 to 500 mg/L) of boron compounds. Sister-chromatid exchange, micronucleus and chromosomal aberration tests were applied to estimate the DNA damage, and biochemical parameters (superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glucose-6-phosphate dehydrogenase, total glutathione, malondialdehyde and total antioxidant capacity) were examined to determine oxidative stress. According to our findings, various boron compounds at low doses were useful in supporting antioxidant enzyme activities in human blood cultures. It was found that the boron compounds do not have genotoxic effects even in the highest concentrations, though in increasing doses they constitute oxidative stress. It is concluded that the tested boron compounds can be used safely, but it is necessary to consider the tissue damages which are likely to appear depending on the oxidative stress.