Hyper-susceptibility of a fusidic acid-resistant mutant of Salmonella to different classes of antibiotics

Fusidic acid resistance (Fus(R)) in Salmonella enterica serovar Typhimurium is caused by mutations in fusA, encoding elongation factor G (EF-G). Pleiotropic phenotypes are observed in Fus(R) mutants. Thus, the fusA1 allele (EF-G P413L) is associated with slow growth rate, reduced ppGpp and RpoS levels, reduced heme levels, and increased sensitivity to oxidative stress. The fusA1-15 allele, (EF-G P413L and T423I) derived from fusA1 in a selection for growth rate compensation, is partially compensated in each of these phenotypic defects but maintains its resistance to fusidic acid. We show here that the fusA1 allele is associated with sensitivity to ultraviolet light and increased susceptibility to the inhibitory action of several unrelated antibiotic classes (beta-lactam, fluoroquinolone, aminoglycoside, rifampicin, and chloramphenicol). The fusA1-15 allele, in contrast, is less susceptible to UV and to other antibiotics than fusA1. The hyper-susceptibility to multiple antibiotics associated with fusA1 and fusA1-15 is revealed in a novel growth competition assay at sub-MIC concentrations, but not in a standard MIC assay.     

Distribution of human kappa locus IGKV2-29 and IGKV2D-29 alleles in Swedish Caucasians and Hong Kong Chinese

Polymorphism in the IGKV2-29 gene was shown to decrease the recombination frequency in B cells and to be important for immune responses to Haemophilus influenzae type b polysaccharide. By using the combination of PCR and restriction enzyme mapping, the distribution of IGKV2D-29 and IGKV2-29 gene alleles was estimated in two geographically and ethnically different groups. We found that V2D-29*01 homozygous individuals were most common in Swedish Caucasians (82%), but less common in the Chinese population of Hong Kong (28%). The homozygous V2D-29*02 genotype was found in 19% Chinese, but only in one Caucasian (1%). The frequency of the heterozygous V2D-29*01/V2D-29*02 genotype was also higher in the Chinese population (46%) compared with the Caucasians (7%). V2-29*01 homozygosity was more frequent among Caucasians (85%) than among Chinese (19%). In contrast, homozygous V2-29*02 individuals were over-represented in the Chinese population (18%), whereas only one was found among Caucasians (1%). Heterozygous V2-29*01/V2-29*02 individuals were also more common in the Chinese (63%) than the Caucasian (15%) population. Most Caucasians had the combination of V2D-29*01/V2D-29*01+V2-29*01/V2-29*01 (74%), while the most common genotype for Chinese was V2D-29*01/V2D-29*02+ V2-29*01/V2-29*02 (41%). Analysis of the association of V2D-29*02 and V2-29*02 alleles demonstrated a high degree of linkage, as for V2D-29*01 with V2-29*01. These data show a significant difference in the distribution of IGKV2D-29 and IGKV2-29 alleles among Swedish Caucasians and Hong Kong Chinese. This may help to explain differences in the occurrence of H. influenzae type b infection in the two populations. Evaluated methods for IGKV2D-29 and IGKV2-29 allele detection can be used for the screening allele polymorphisms in other particular patient groups.     

Antioxidant properties of ganglioside micelles

Antioxidant activity of gangliosides GM1 and GT1b in the Fenton type of reaction was investigated by EPR spectroscopy using DMPO as a spin trap. Hydroxyl radical spin adduct signal intensity was significantly reduced in the presence of gangliosides at their micellar concentrations. Mean micellar hydrodynamic diameter was not changed, whereas significant changes in negative Zeta potential values were observed as evidenced by Zetasizer Nano ZS. This study showed that the primary mode of ganglioside action was not due to direct scavenging of OH·, but rather to the inhibition of hydroxyl radical formation. This phenomenon is related to the ability of ganglioside micelles to bind oppositely charged ferrous ions, thus reducing their concentration and consequently inhibiting OH· formation.     

Completeness and changes in registered data and reporting bias of randomized controlled trials in ICMJE journals after trial registration policy

Objective

We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.

Methods

For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.

Results

RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly ‘Key secondary outcomes’ (44.1% RCTs) and ‘Primary outcome’ (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ² ₁ = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.

Conclusions

ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials.     

Alien invasive neophytes of the Southeastern part of the Pannonian Plain

Floristic diversity in the Pannonian Plain is the result of mosaic habitat composition, characterized by steppes, saline meadows, and lowland forests along major rivers. In the last few centuries, the flora has become enriched by species introduced by human activities, such as colonization and industrialization. Presently it consists of nearly 1800 species. As a result of 30 years of field research as well as herbarium and literature searches, a list of invasive alien neophytes has been compiled and is presented here. The list includes 152 species, classified as either naturalized, casual, or unknown. One of the species is listed in Red Book of Serbian Flora. Eighty species are naturalized, and 61 are casual species. The majority of the introduced flora originates from North America (66) and the Old World (43). Most alien invasive species of the Southeastern part of the Pannonian Plain, were introduced accidentally by seed material or deliberately by nursery saplings. The annual and perennial herbaceous plants, which flower in the summer and summer-autumn periods, are represented in the greatest numbers. The alien flora was further analyzed with respect to taxonomy, life forms, pollination, and seed dispersal mode. The greatest number of alien species appears in anthropogenic and semi-natural habitats (59). In natural habitats, 45 invasive taxa were recorded, representing a conservation threat to biodiversity.     

The intriguing mission of neuropeptide Y in the immune system

For many years, the central nervous system and the immune system were considered two autonomous entities. However, extensive research in the field of neuroimmunomodulation during the past decades has demonstrated the presence of different neuropeptides and their respective receptors in the immune cells. More importantly, it has provided evidence for the direct effects of neuropeptides on the immune cell functions. Neuropeptide Y (NPY) is generally considered the most abundant peptide in the central and peripheral nervous system. However, it is also distinguished by exhibiting pleiotropic functions in many other physiological systems, including the immune system. NPY affects the functions of the cells of the adaptive and innate immunity. In this respect, NPY is known to modulate immune cell trafficking, T helper cell differentiation, cytokine secretion, natural killer cell activity, phagocytosis and the production of reactive oxygen species. The specific Y receptors have been found in immune cells, and their expression is amplified upon immune stimulation. Different Y receptor subtypes may mediate an opposite effect of NPY on the particular function, thus underlining its regulatory role. Since the immune cells are capable of producing NPY upon appropriate stimulation, this peptide can regulate immune cell functions in an autocrine/paracrine manner. NPY also has important implications in several immune-mediated disorders, which affirms the clear need for further investigation of its role in either the mechanisms of the disease development or its possible therapeutic capacity. This review summarises the key points of NPY’s mission throughout the immune system.     

Insight into Danube sturgeon life history: trace element assessment in pectoral fin rays

Sturgeon populations in the Danube River have experienced severe decline during the last several decades, mostly due to the poorly regulated fishery, river fragmentation and water pollution. This study focuses on gaining better understanding of sturgeon life history primarily by addressing the assessment of microelement accumulation in sturgeon pectoral fin rays, especially of strontium and calcium, as a method that can reveal migration patterns of anadromous sturgeons. Analysis was performed on pectoral fin samples of three anadromous Danube sturgeon species (beluga, Russian sturgeon and stellate sturgeon) by the use of a Nuclear Microprobe technique. The most frequent pattern in analyzed samples was represented by a low Sr:Ca ratio in the innermost annuli, followed by an increased ratio in the middle annuli segment, and often with a decreased ratio in the outermost annuli. Probability density estimate has revealed three distinguished maxima of the Sr:Ca ratio, 7.08 × 10⁻³, 8.98 × 10⁻³ and 9.90 × 10⁻³, which might correspond, respectively, to fresh, brackish and saltwater. Although the analysis of the Sr:Ca ratio in sturgeon pectoral fin rays has revealed changes that might indicate probable migration between habitats with different water salinity, further studies are needed for improvement of this method. This study represents the first analysis of this kind that was conducted on sturgeon species from the Black Sea basin.     

Predicting apricot phenology using meteorological data

The main objective of this study was to develop feasible, easy to apply models for early prediction of full flowering (FF) and maturing (MA) in apricot (Prunus armeniaca L.). Phenological data for 20 apricot cultivars grown in the Belgrade region were modeled against averages of daily temperature records over ten seasons for FF and eight seasons for MA. A much stronger correlation was found between the phenological timing and temperature at the very beginning than at the end of phenophases. Also, the length of developmental periods were better correlated to daily maximum than to daily minimum and mean air temperatures. Using prediction models based on daily maximum temperatures averaged over 30-, 45- and 60-day periods, starting from 1 January for FF prediction and from the date of FF for MA prediction, the onset of examined phenophases in apricot cultivars could be predicted from a few weeks to up to 2 months ahead with acceptable accuracy. The mean absolute differences between the observations and cross-validated predictions obtained by 30-, 45- and 60-day models were 8.6, 6.9 and 5.7 days for FF and 6.1, 3.6 and 2.8 days for MA, respectively. The validity of the results was confirmed using an independent data set for the year 2009.     

Inhibition of rat synaptic membrane Na⁺/K⁺-ATPase and ecto-nucleoside triphosphate diphosphohydrolases by 12-tungstosilicic and 12-tungstophosphoric acid

The in vitro influence of Keggin structure polyoxotungstates, 12-tungstosilicic acid, H(4)SiW(12)O(40) (WSiA) and 12-tungstophosphoric acid, H(3)PW(12)O(40) (WPA), and monomer Na(2)WO(4) × 2H(2)O on rat synaptic plasma membrane (SPM) Na(+)/K(+)-ATPase and E-NTPDase activity was studied, whereas the commercial porcine cerebral cortex Na(+)/K(+)-ATPase served as a reference. Dose-dependent Na(+)/K(+)-ATPase inhibition was obtained for all investigated compounds. Calculated IC(50) (10 min) values, in mol/l, for SPM/commercial Na(+)/K(+)-ATPase, were: 3.4 × 10(-6)/4.3 × 10(-6), 2.9 × 10(-6)/3.1 × 10(-6) and 1.3 × 10(-3)/1.5 × 10(-3) for WSiA, WPA and Na(2)WO(4) × 2H(2)O, respectively. In the case of E-NTPDase, increasing concentrations of WSiA and WPA induced its activity reduction, while Na(2)WO(4) × 2H(2)O did not noticeably affect the enzyme activity at all investigated concentrations (up to 1 × 10(-3)mol/l). IC(50) (10 min) values, obtained from the inhibition curves, were (in mol/l): 4.1 × 10(-6) for WSiA and 1.6 × 10(-6) for WPA. Monolacunary Keggin anion was found as the main active molecular species present under physiological conditions (in the enzyme assays, pH 7.4), for the both polyoxotungstates solutions (1 mmol/l), using Fourier transform infrared (FT-IR) and micro-Raman spectroscopy. Additionally, commercial porcine cerebral cortex Na(+)/K(+)-ATPase was exposed to the mixture of Na(2)WO(4) × 2H(2)O and WSiA at different concentrations. Additive inhibition effect was achieved for lower concentrations of Na(2)WO(4) × 2H(2)O/WSiA (≤ 1 × 10(-3)/4 × 10(-6) mol/l), while antagonistic effect was obtained for all higher concentrations of the inhibitors.     

Interactions of the eNOS and ACE genes and cigarette smoking in chronic obstructive pulmonary disease

BackgroundChronic obstructive pulmonary disease (COPD) is a complex disorder with unexplained heritability. Interactions of genetic and environmental factors are thought to be crucial in COPD. So, we aim to examine interactions of the endothelial nitric oxide synthase (eNOS) and angiotensin converting enzyme (ACE) genes and cigarette smoking in COPD.MethodsThe eNOS G 894T and ACE ID variants were analyzed in 122 COPD patients and 200 controls from Serbia. The effect of the variants on COPD was assessed by logistic regression. Interactions between eNOS, ACE and cigarette smoking in COPD were evaluated using a case-control model. Interaction between the genes was analyzed in silico.ResultsNo effect of the eNOS G 894T and ACE ID variants on COPD was found in our study. Gene-gene interaction between the eN OS T T and A CE D was identified (p=0.033) in COPD. The interaction is realized within the complex network of biochemical pathways. Gene-environment interactions between the eNOS T and cigarette smoking (p=0.013), and the ACE II and cigarette smoking (p=0.009) were detected in COPD in our study.ConclusionsThis is the first research to reveal interactions of the eNOS and ACE genes and cigarette smoking in COPD progressing our understanding of COPD heritability and contributing to the development of appropriate treatments