Genetic analysis of delta helD and delta uvrD mutations in combination with other genes in the RecF recombination pathway in Escherichia coli: suppression of a ruvB mutation by a uvrD deletion

Helicase II (uvrD gene product) and helicase IV (helD gene product) have been shown previously to be involved in the RecF pathway of recombination. To better understand the role of these two proteins in homologous recombination in the RecF pathway [recBCsbcB(C) background, we investigated the interactions between helD, uvrD and the following RecF pathway genes: recF, recO, recN and ruvAB. We observed synergistic interactions between uvrD ant the recF, recN, recO and recG genes in both conjugational recombination and the repair of methylmethane sulfonate (MMS)-induced DNA damage. No synergistic interactions were detected between helD and the recF, recO and regN genes when conjugational recombination was analyzed. We did, however, detect synergistic interactions between helD and recF/recO in recombinational repair. Surprisingly, the uvrD deletion completely suppressed the phenotype of a ruvB mutation in a recBCsbcB(C) background. Both conjugational recombination efficiency and MMS-damaged DNA repair proficiency returned to wild-type levels in the deltauvrDruvB9 double mutant. Suppression of the effects of the ruvB mutation by a uvrD deletion was dependent on the recG and recN genes and not dependent on the recF/O/R genes. These data are discussed in the context of two "RecF" homologous recombination pathways operating in a recBCsbcB(C) strain background.     

Effects of Sexually Objectifying Media on Self-Objectification and Body Surveillance in Undergraduates: Results of a 2-Year Panel Study

This study used objectification theory (B. L. Fredrickson & T.-A. Roberts, 1997) to predict that the media's insidious practice of objectifying bodies socializes individuals to take an outsider's perspective on the physical self (i.e., self-objectify) and to habitually monitor their appearance (i.e., engage in body surveillance). To test these hypotheses, a 2-year panel study using an undergraduate sample was conducted. Cross-lagged path models showed that exposure to sexually objectifying television measured during Year 1 increased trait self-objectification (trait SO) during Year 2 for both women and men. At the same time, trait SO during Year 1 decreased exposure to sexually objectifying television during Year 2, suggesting that both male and female participants selectively avoided sexually objectifying television based on antecedent trait SO. Moreover, exposure to sexually objectifying television and magazines increased body surveillance for men only. The discussion focuses on the process by which the media create body-focused perceptions.     

Column Test Studies of Ochre Biofilm Formation in Geotextile Filters

This paper presents a study of ochre formation in geotextile filters. Ochre is a substance found sticking to solid surfaces of drainage systems that may cause clogging. The accumulation of such materials in a drainage system may have undesirable implications, such as a decrease in drainage flow capacity and an increase in soil pore pressure; instability of soil masses and retaining systems; and alteration of the direction of flow and development of pipes. Ochre formation is the result of microbial activities on iron compounds naturally found in seepage water. Even though geotextiles have been widely used in drainage systems, very few studies have considered ochre formation in the tests. Laboratory column filter tests were conducted to simulate the ochre formation process under similar conditions to those in geotechnical works and to assess the long-term performance of a geotextile. Ochre is most likely to be formed at an aerated/nonaerated interface in the filter. In order to obtain this condition, the underneath face of the filters was opened to the atmosphere. Three different types of geotextile—nonwoven polyester, nonwoven polypropylene, and woven polypropylene—were used in the tests. Control tests were also conducted with a sand filter to provide a basis for comparison. Hydraulic conductivity changes and iron retention within the permeameters were monitored throughout the tests. Ochre was formed under the presence of iron ions and iron bacteria. During the test period, the filters were not clogged to such an extent as to induce a global reduction in the permeability of the drainage system. Nevertheless, at the end of the tests a considerable amount of ochre was found in all filters and there was a significant variation in the permeability of the geotextile filters when tested in isolation. These studies may contribute to discovering whether ochre can be considered as a biofilm, evaluating the clogging potential and defining mitigating measures.     

Monitoring furosemide in racehorses participating in an EIPH program

We report a rare case of temporary and severe hypercalcemia: the patient, a 69-year-old woman, was admitted to Osaka City University Hospital on July 25, 1992, for severe hypercalcemia. The laboratory data on admission revealed severe hypercalcemia (14.9 mg/dl) and renal dysfunction with increased serum creatinine level (2.9 mg/dl). The urinary excretion of pyridinoline and deoxypyridinoline was increased, and serum levels of parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D were decreased. The data suggested that increased bone resorption was a probable main factor in the development of the hypercalcemia. The development of hypercalcemia seemed to be of acute onset because of (1) her severe symptoms caused by hypercalcemia and (2) impaired renal function which was improved after normalization of serum calcium level. Combination therapy with saline infusion and furosemide was administered, and there was a gradual decrease and subsequent normalization of serum calcium level along with serum creatinine. Even 8 months after discontinuation of the therapy for hypercalcemia, the serum calcium level remained within the normal range. The measured values of serum factors which are suspected to have a hypercalcemic effect, such as PTH, parathyroid hormone-related peptide and the cytokines (interleukin-1 alpha, interleukin-1 beta, interleukin-2, interleukin-6 and tumor necrosis factor-alpha) were all within the normal range. In summary, the hypercalcemia in this patient was regarded to be a type of disequilibrium hypercalcemia due to a combination of increased bone resorption and decreased renal capacity to excrete calcium. Furthermore, since it was temporary and did not recur even in the absence of treatment, the hypercalcemia was concluded to have developed due to an imbalance in calcium regulation rather than as a result of organic disease.     

Radiation resistance and virulence of Listeria monocytogenes Scott A following starvation in physiological saline

The influence of starvation on the resistance of Listeria monocytogenes Scott A to electron beam irradiation in 0.85% (wt/vol) NaCl (saline) and in ground pork was investigated. Exponential- or stationary-phase cells (control) were grown at 35 degrees C in tryptic soy broth supplemented with 0.6% yeast extract. Washed cells were starved for 12 days in saline, and virulence of the pathogen was evaluated at 0, 8, and 12 days during starvation. Samples of saline and irradiation-sterilized ground pork, inoculated with control or starved cells, were irradiated at doses ranging from 0.0 to 2.5 kGy. L. monocytogenes survivors were determined by plating diluted samples of saline or pork on tryptic soy agar supplemented with 0.6% yeast extract and counting bacterial colonies following incubation (35 degrees C, 48 h). Virulence of starved cells and control was not significantly different (P > 0.05). Cells exhibited the highest radiation resistance at 8 days of starvation. Irradiation (0.5 kGy) in saline resulted in approximately 7.14, 5.55, and 2.38 log reduction in exponential, stationary, and starved cells, respectively. Irradiation of ground pork at 2.5 kGy reduced controls by approximately 6.0 log, whereas starved cells were reduced by only 3.8 log. Starved cells consistently exhibited higher irradiation D10-values than controls (P < 0.05). D10-values for exponential, stationary, and starved cells were 0.07, 0.09, and 0.21 kGy and 0.35, 0.42, and 0.66 kGy in saline and ground pork, respectively. These results indicate that starvation cross-protects L. monocytogenes Scott A against radiation inactivation and should be considered when determining this pathogen's irradiation D-value.     

Quantification of Protein‐Induced Membrane Remodeling Kinetics In Vitro with Lipid Multilayer Gratings

The dynamic self‐organization of lipids in biological systems is a highly regulated process that enables the compartmentalization of living systems at micro‐ and nanoscopic scales. Consequently, quantitative methods for assaying the kinetics of supramolecular remodeling such as vesicle formation from planar lipid bilayers or multilayers are needed to understand cellular self‐organization. Here, a new nanotechnology‐based method for quantitative measurements of lipid–protein interactions is presented and its suitability for quantifying the membrane binding, inflation, and budding activity of the membrane‐remodeling protein Sar1 is demonstrated. Lipid multilayer gratings are printed onto surfaces using nanointaglio and exposed to Sar1, resulting in the inflation of lipid multilayers into unilamellar structures, which can be observed in a label‐free manner by monitoring the diffracted light. Local variations in lipid multilayer volume on the surface is used to vary substrate availability in a microarray format. A quantitative model is developed that allows quantification of binding affinity (K _D) and kinetics (k_on and k_off). Importantly, this assay is uniquely capable of quantifying membrane remodeling. Upon Sar1‐induced inflation of single bilayers from surface supported multilayers, the semicylindrical grating lines are observed to remodel into semispherical buds when a critical radius of curvature is reached.     

Optimisation of the secondary ball mill using an on-line ball and pulp load sensor – The Sensomag

The ball load and pulp load have a significant influence on the ball mill product size and production capacity. To improve the circuit performance at industrial scale these variables must be tweaked to levels where the plant can get grind and capacity benefits. In most grinding circuits the influence of these variables are not quantified because it is difficult to obtain precise measurements of the pulp load for an industrial scale mill and the conventional method of obtaining ball load measurements that involves crash stops is not attractive. A comprehensive investigation was performed on an industrial scale mill to quantify the effects of both ball and pulp load. A wide range of ball and pulp loads were tested and the findings are reported in this paper. The Sensomag, a sensor developed by Magotteaux, was used to obtain ball and pulp load measurements during the experimental work.     

Phthalocyanine- and Calixarene-Templating Effect on the Catalytic Performance of Solid Supported Vanadates

Abstract  

Catalytic performance of solid supported monovanadate catalysts toward oxidation of propane is significantly affected by the templating effect of: (1) pretreatment of the solid support with calixarene derivatives before deposition of ammonium vanadate, (2) direct deposition of vanadyl phthalocyanine as the vanadate precursor. This effect is believed to be linked to the accessibility of the active sites, and was studied in comparison with a reference mesoporous support.