A role for interaction of the RNA polymerase flap domain with the sigma subunit in promoter recognition

In bacteria, promoter recognition depends on the RNA polymerase sigma subunit, which combines with the catalytically proficient RNA polymerase core to form the holoenzyme. The major class of bacterial promoters is defined by two conserved elements (the -10 and -35 elements, which are 10 and 35 nucleotides upstream of the initiation point, respectively) that are contacted by sigma in the holoenzyme. We show that recognition of promoters of this class depends on the "flexible flap" domain of the RNA polymerase beta subunit. The flap interacts with conserved region 4 of sigma and triggers a conformational change that moves region 4 into the correct position for interaction with the -35 element. Because the flexible flap is evolutionarily conserved, this domain may facilitate promoter recognition by specificity factors in eukaryotes as well.     

The Characterization of Heavy Metals in the Grapevine (Vitis vinifera) Cultivar Rkatsiteli and Wild Blackberry (Rubus fruticosus) from East Serbia by ICP-OES and BAFs

Inductively coupled plasma optical emission spectroscopy, in combination with calculation of various biological factors, was used in this study not only for a simple illustration of the present status of some essential and non-essential metals such as copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), arsenic (As), and cadmium (Cd) in the grapevine cultivar Rkatsiteli and wild blackberry from East Serbia but also for the estimation of plant bioaccumulation potentials. Great majority of detected metal concentrations were in normal ranges except in few cases: Zn concentrations were at the level of deficiency in almost all plant parts, and some Cu and As concentrations were at the levels that could be considered phytotoxic. Biological accumulation factors provided very informative data on metal accumulation and translocation in both plants and pointed to low accumulation rates of metals except in the case of Cu, Zn, and As in some wild blackberry tissues.     

Identification of PCR markers linked to different Or genes in sunflower

Broomrape is a parasitic plant that significantly decreases yield of sunflower. Breeding for resistance has proved to be the most efficient method for suppressing broomrape infestation in the field; however, new races of parasite constantly emerge, and new resistance genes need to be discovered and introduced into cultivated sunflower lines. The aim of this work was to test SSR markers from linkage group 3 (LG3) to investigate whether they could be used for identification of a particular Or gene. Twenty sunflower inbred lines were used, and polymorphism between the lines with various resistance genes and genetic background was investigated. The used markers revealed DNA polymorphism between the investigated lines. Strong association of markers from LG3 with Or₆, as well as Or₄ and Or₂ genes, was found. Identified markers could be used for introduction of these resistance genes into commercial sunflower lines and for establishment and identification of differential lines.     

Analysis of genetic diversity among Macrophomina phaseolina (Tassi) Goid. isolates from Euro-Asian countries

Journal of Plant Diseases and Protection - The study assessed the genetic variability among Macrophomina phaseolina (Tassi) Goid. isolates originating from six different countries (Turkey,...     

Early shoot and root growth dynamics as indicators for the survival of black poplar cuttings

The relationship between early root and shoot formation at the beginning of the vegetation period and cutting survival on sandy and loamy fluvisol for 14 genotypes of black poplars was analyzed. Considerable cutting mortality was observed only within the first 80 days since planting. Intensive root formation in the first 20 days since the planting and vigorous shoot growth and development in subsequent 20 days was observed in easy-to-root genotypes. Coefficients of correlation revealed close relationship between early root and shoot growth and development and cutting survival of tested genotypes. The obtained results could be used in the breeding process, as well as for the design of cultivar-adjusted nursery and plantation establishment technology. Tested shoot characteristics, were found to be especially interesting since they could be measured rapidly, by non-destructive means.     

Cabbage (Brassica oleracea var. capitata) as possible indicator of wartime metal and metalloid contamination in eastern Croatia (ICP-MS method)

Biomonitoring of the local population and environmental monitoring in eastern Croatia have revealed abnormalities in metal and metalloid distribution that could be related to war activities during the 1990s. The goal of this study was to determine whether there are differences in the concentrations of metals and metalloids by comparing locations of high and low-intensity combat activity; we also evaluated a possible connection between metal contamination in soil and in humans. We sampled 14 locations and measured the concentrations of 20 war related metals and metalloids (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Ni, Pb, Sb, Si, Sr, U, V and Zn). The results of principal components analysis showed two main clusters: locations Dopsin and Dalj (both characterized by high-intensity combat activity), where the concentrations of most elements (except Hg) were increased. Although the concentrations of metals and metalloids in cabbage samples collected in eastern Croatia did not exceed the maximum allowed values, the results of our study confirmed existance of environmental ‘hotspot’ with higher concentrations of war metals and metalloids. Our findings indicate that there is a possible common source and mechanism of transferring metals from the environment to the population.     

Examining the Relationships Between the Activities of 3H in Precipitation and 137Cs in Ground-Level Air in Belgrade City Area

Specific activity of tritium (³H) in precipitation and specific activity of ¹³⁷Cs in ground-level air were monitored at three locations in Belgrade (Meteorological Station of Belgrade at Zeleno Brdo (ZB), Meteorological Station Usek (USEK), and Vin?a Institute of Nuclear Sciences (VINS)). Data presented cover the period 1985?C1997 for ¹³⁷Cs for all locations and 1985?C2009 (ZB), 1988?C1997 (USEK), and 1988?C2009 (VINS) for ³H. Concentrations of ³H in precipitation have been determined using electrolytic enrichment and liquid scintillation spectrometer LKB-Wallac 1219 RackBeta. The activity of ¹³⁷Cs in air was determined on an HPGe detector (Canberra, relative efficiency 23?%). ³H concentrations in precipitation ranged from 0.40?±?0.08 to 74.6?±?5.2?Bq?l^?1 decreasing with distance from the nuclear facilities. Significantly higher tritium levels were measured in samples in VINS compared with those from an off-site location. The observed seasonal variations of tritium concentration indicate the stratospheric source of tritium. Increases in activity concentration of ¹³⁷Cs in the atmosphere were observed after the nuclear plant accident at Chernobyl in April 1986. The concentrations obtained for ¹³⁷Cs in 1986 were compared with the integrated air concentrations of ¹³⁷Cs in the region. The increases of ¹³⁷Cs air concentrations in 1987 and 1988 were attributed to local resuspensions from the ground. Since 1989, the activity level before the accident has been obtained. The average monthly concentrations of ¹³⁷Cs in ground-level air were shown spread maximum in spring?Csummer period and pronounced maximum during winter. The obtained results were statistically analyzed, i.e., the following parameters were determined: tritium deposition, monthly activities of ³H and ¹³⁷Cs, seasonal indices, radionuclide loading indices, and linear correlation coefficients.     

Changes in the caecal microflora of chickens following Clostridium perfringens challenge to induce necrotic enteritis

Necrotic enteritis is a disease of considerable economic importance to the global poultry industry. Clostridium perfringens has long been recognised as the etiological agent of the disease. However, disease initiation and progression is complex and appears to be precipitated by a range of predisposing factors. The present study investigated microbial interactions in the caecum of birds challenged with C. perfringens that developed necrotic enteritis. Bacterial populations of healthy and diseased birds, across two independent animal trials, were characterised by pyrosequencing of the V1-V3 region of 16S rRNA genes. Significant changes in the microbiota of infected birds were detected. Most of the affected bacterial species, including a number of butyrate producers, were reduced in abundance in infected birds compared to uninfected controls and a number of phylotypes, classified as Weissella species, were also more abundant in healthy birds. Conversely, some bacterial groups were more abundant in the C. perfringens-infected birds, for example, members of an unclassified order of Mollicutes showed a 3.7-fold increase in abundance in infected birds. Representative sequences from this novel order shared 99% identity with sequences previously detected in intestinal microbiota of chickens and humans, and have previously been shown to be represented in a number of samples originating from irritable bowel syndrome disease patients. We speculate that these newly identified perturbations in the composition of caecal microflora may play a role in the development and manifestation of necrotic enteritis.     

Effect of nicosulfuron on plant traits of Xanthium strumarium

Journal of Plant Diseases and Protection - Field experiments were conducted in 2008 and 2009 at the Experimental Field Institute Padinska Skela PKB Agroe-konomik, near Belgrade, to quantify effects...     

Monitoring of Aerosol and Fallout Radioactivity in Belgrade After the Fukushima Reactors Accident

After the accident in Fukushima reactors, a daily monitoring programme was initiated in two laboratories in Belgrade, one at the Vin??? Institute for Nuclear Sciences and the other at Institute for Occupational Health Karajovic. Samples of aerosol and fallout, as well as the random samples of food and water, were collected and analysed, using gross alpha/beta and gamma spectrometry, in order to establish the presence of traces of isotopes indicating Fukushima fallout. Gamma spectrometry measurement of these samples showed clear evidence of fission products ¹³¹I, ¹³⁴Cs and ¹³⁷Cs wtihin 2?weeks after the accident. The activity diminished with time due to dispersion in air and, in case of ¹³¹I, short half-life.