Sensitive determination of carbidopa through the electrochemiluminescence of luminol at graphene‐modified electrodes

Using the concept of electrogenerated chemiluminescence (ECL), a sensitive analytical method for the determination of carbidopa is described. Electro‐oxidation of carbidopa on the surface of a graphene oxide (GO)‐modified gold electrode (GE) leads to enhancement of the weak emission of oxidized luminol. Under optimum experimental conditions, the ECL signal increases linearly with increasing carbidopa concentrations over a range of 1.0 × 10^‐9–1.7 × 10^‐7 M, with a detection limit of 7.4 × 10^‐10 M. The proposed ECL method was successfully used for the determination of carbidopa in urine samples. Copyright © 2014 John Wiley & Sons, Ltd.     

Host-Guest Interactions as a Model for the Solvent Influence on the Conformational Populations in [2.2.2.2]Paracyclophane

The interaction of a number of small organic molecules with the two lowest energy minimum conformations of [2.2.2.2]paracyclophane (4°-PCP), 1 and 2, are studied by MMP2(87) force field calculations. Formations of nesting as well as inclusion complexes were identified on the potential energy surface. With CH₂Cl₂ and CHCl₃ used as guests, the nesting complexes are lower in energy than the inclusion ones with both conformations 1 and 2. Furthermore, the nesting complexes with 2 are found to be more stable than the nesting ones with 1. Formation of the double nesting complexes of CH₂Cl₂ and CHCl₃ with 1 and 2 raise the difference in complexation energy in favour of 2. The preference of 4°-PCP for the form 2 in solution is explained based on the above analysis, although 2 is calculated to be 0.2 kcal·mol^–1 higher in steric energy than 1 in the gas phase.Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s0089490050218     

Molecular Dynamics Study of the Human Beta-defensins 2 and 3 Chimeric Peptides with the Cell Membrane Model of Pseudomonas aeruginosa

International Journal of Peptide Research and Therapeutics - Pseudomonas aeruginosa is a unique microorganism among the antibiotic-resistant microbial pathogens. Among the various therapeutic...     

Characterization of bacterial populations recovered from the teat canals of lactating dairy and beef cattle by 16S rRNA gene sequence analysis

Bovine mastitis is of major concern to the dairy industry worldwide. The bovine teat canal is the primary route through which pathogens enter the mammary gland. The microflora of the teat canals of dairy and beef cattle was investigated by analysis of 16S rRNA gene sequences. The goal was to examine the global difference between dairy cattle, which are sanitized on a regular basis, and beef cattle, which receive little sanitary management. A diverse population of 16S rRNA gene sequences was recovered from both the dairy and the beef herd samples, with diversity higher in the beef sample. Analysis revealed the presence of 90 operational taxonomic units (OTUs) among 156 sequences, with 45 OTUs in the dairy sample and 53 OTUs in the beef sample. Only eight OTUs were common to both samples. Members of the classes Clostridia and Bacilli dominated both samples, followed by Actinobacteria and Proteobacteria. The dairy sample contained a cluster (20/80 clones) of Staphylococcaceae members, seven of which were identifiable as coagulase-negative Staphylococcus species. The beef sample was dominated by members of the genus Clostridia, many of which have not been previously cultured. The results suggest that the microorganisms present in the bovine teat canal are more diverse than previously described.     

Cytokine response following transthoracic and transhiatal esophagectomy in patients with esophageal cancer

Curative esophageal resection is usually performed using either a transthoracic (TT) or transhiatal (TH) approach. Forty patients with esophageal squamous cell carcinoma who underwent esophagectomies (24 TT and 16 TH), 12 patients who underwent surgery for gastric cancer, and 16 healthy individuals were enrolled in this study. Blood samples were taken from the patients, pre- and post-surgery. The levels of synthesis of T-helper 1 and 2 cytokines were assessed in vitro in the presence of mitogen. Our initial data indicated that at admission, 24 h before surgery, blood cells from both groups of esophageal cancer patients produced significantly lower levels of the Th1 cytokines, IFN-gamma and IL-2 than those from cells of healthy donors. Cells collected from gastric cancer patients prior to surgery produced intermediate levels of IFN-gamma and IL-2: significantly lower than healthy donors, and slightly more (non-significant) than esophageal cancer patients. These results contrast with those for the production of Th2 cytokines prior to surgery, which did not differ significantly between any groups: either the esophageal or gastric cancer patients, or healthy donors. Th1 and Th2 cytokine production was then studied using blood cells collected seven days after surgery. Cells from both groups of esophageal cancer patients, undergoing either TT or TH surgery, produced significantly lower levels of the Th1 cytokines, IFN-gamma and IL-2 than those from cells of gastric cancer patients who had undergone surgery. Postoperative and preoperative production was compared. For patients who had undergone TT esophageal resection, we observed that the post-operative production of IL-2, IL-5 and IL-13 was significantly lower than the pre-operative production of those cytokines. Such reduced post-operative compared to pre-operative production was only significant in patients who had undergone TT esophagectomy. A similar, but non-significant trend was observed in patients who had undergone either TH esophagectomy, or gastrectomy. The results indicate that digestive tract cancer patients, both esophageal and gastric, have (prior to surgery), a significantly reduced, basal, mitogen-induced production of Th1 but not of Th2 cytokine. Post-operatively, a significantly reduced production of Th1 and Th2 cytokines, except for IFN-gamma, was observed only in patients who had undergone surgical esophageal resection using the TT method.     

Phylogenetic study of SIVcpz MT145 virus based on proteome and genome analysis

Molecular phylogenetic studies were performed by the alignment of protein/nucleotide sequences of human/simian immunodeficiency virus (HIV/SIV), followed by the construction of phylograms according to maximum likelihood method. We aimed to investigate the evolutionary relationship of the recombinant SIVcpzMT145, to other well-known SIVcpz and HIV-1 viruses. Expectedly, MT145 follows the rule of feasible recombination occurrence in SIVcpz clade as to it consists several recombinations in different genome sites including gag, Pol, and Env region. Phylograms indicated that in Pol gene, MT145 is more related to GAB1 and CAM13 SIVs; while in Env gene, it has a closed relationship to GAB2 SIV. Moreover, MT145 differs from other SIVcpzPtt strains in the Env V3 loop having the QIGPAMT motif (same as HIV-1N), instead of usual QIGPGMT motif in these strains. Data indicated that the Env proteins contain considerable amino acid sequence diversification. Overall, this study suggests that, parts of the Gag and especially Vpu/Env gene sequences of SIVcpzMT145 were derived from an unknown SIVcpz lineage ancestral to HIV-1 group M/MB66.     

Investigation on functional and numerical responses of Encarsia acaudaleyrodis parasitizing Bemisia tabaci on cucumber

Functional and numerical responses of Encarsia acaudaleyrodis Hayat parasitizing Bemisia tabaci Gennadius were investigated under laboratory conditions. Newly emerged pairs of parasitoids were confined for 24 h in 8 cm Petri dishes together with 5, 10, 20, 40, 60, or 100 individuals of B. tabaci at their third nymphal stage. The parasitoid exhibited a type II functional response, attacking up to 9.6 nymphs when 100 had been provided. The rate of attack and handling time were 0.0554 and 2.3068 h, respectively. The number of eggs deposited by a single parasitoid depended on the number of host individuals, the maximum being 44.4 when the number of nymphs was 100. At the above-mentioned densities, the parasitoid lived 8.5 days on average.     

Detection of Wolbachia pipientis, including a new strain containing the wsp gene,in two sister species of Paraphlebotomus sandflies,potential vectors of zoonotic cutaneous leishmaniasis

Individual, naturally occurring Phlebotomus mongolensis and Phlebotomus caucasicus from Iran were screened for infections with the maternally inherited intracellular Rickettsia-like bacterium Wolbachia pipientis via targeting a major surface protein gene (wsp). The main objective of this study was to determine if W. pipientis could be detected in these species. The sandflies were screened using polymerase chain reaction to amplify a fragment of the Wolbachia surface protein gene. The obtained sequences were edited and aligned with database sequences to identify W. pipientis haplotypes. Two strains of Wolbachia were found. Strain Turk 54 (accession {"type":"entrez-nucleotide","attrs":{"text":"EU780683","term_id":"212725653","term_text":"EU780683"}}EU780683) is widespread and has previously been reported in Phlebotomus papatasi and other insects. Strain Turk 07 (accession {"type":"entrez-nucleotide","attrs":{"text":"KC576916","term_id":"499068248","term_text":"KC576916"}}KC576916) is a novel strain, found for first time in the two sister species. A-group strains of W. pipientis occur throughout much of the habitat of these sandflies. It is possible that Wolbachia is transferred via horizontal transmission. Horizontal transfer could shed light on sandfly control because Wolbachia is believed to drive a deleterious gene into sandflies that reduces their natural population density. With regard to our findings in this study, we can conclude that one species of sandfly can be infected with different Wolbachia strains and that different species of sandflies can be infected with a common strain.     

A Proline/Arginine-Rich End Leucine-Rich Repeat Protein (PRELP) Variant Is Uniquely Expressed in Chronic Lymphocytic Leukemia Cells

Proline/arginine-rich end leucine-rich repeat protein (PRELP) belongs to the small leucine-rich proteoglycan (SLRP) family, normally expressed in extracellular matrix of collagen-rich tissues. We have previously reported on another SLRP, fibromodulin (FMOD) in patients with chronic lymphocytic leukemia (CLL). PRELP is structurally similar to FMOD with adjacent localization on chromosome 1 (1q32.1). As cluster-upregulation of genes may occur in malignancies, the aim of our study was to analyze PRELP expression in CLL. PRELP was expressed (RT-PCR) in all CLL patients (30/30), as well as in some patients with mantle cell lymphoma (3/5), but not in healthy donor leukocytes (0/20) or tumor samples from other hematological malignancies (0/35). PRELP was also detected in CLL cell-lines (4/4) but not in cell-lines from other hematological tumors (0/9). PRELP protein was detected in all CLL samples but not in normal leukocytes. Deglycosylation experiments revealed a CLL-unique 38 kDa core protein, with an intact signal peptide. This 38 kDa protein was, in contrast to the normal 55 kDa size, not detected in serum which, in combination with the uncleaved signal peptide, suggests cellular retention. The unique expression of a 38 kDa PRELP in CLL cells may suggest involvement in the pathobiology of CLL and merits further studies.