Transcription of the Campylobacter jejuni cell division gene ftsA

Abstract Long-lived radioactive waste will be buried several hundred meters below ground in metal canisters surrounded by a buffer of compacted bentonite. Sulfate-reducing bacteria present in the bentonite may induce canister corrosion by production of hydrogen sulfide. Here we show that survival of sulfate-reducing bacteria in bentonite depends on the availability of water and that compacting a high quality bentonite to a water activity ( a _w) of 0.96 was lethal for the species investigated.     

Salvaged-Wetland Soil as a Technique to Improve Aquatic Vegetation at Created Wetlands in Wyoming,USA

Aquatic plants usually establish following wetland creation from a variety of mechanisms including animal transport, inflows from nearby wetlands, wind dispersal, and seed banks if they are available. However, at created wetlands that are isolated from natural wetlands, aquatic plant communities may not establish even after 10 or more years. One method of improving the establishment of aquatic plants is through the use of salvaged-marsh soils. Using this method, wetland soil from a donor site is collected and spread across the basin of the created wetland. When the proper hydrologic regime is reached at the created site, the seed bank from the donor soil is then present to take advantage of the uncolonized site. Over 1500 wetlands have been created in northeast Wyoming, USA from bentonite mining and most of them have not developed submersed and emergent plant communities due to isolation from plant sources. Our goal was to evaluate the effectiveness of using salvaged-wetland soil as a tool for improving plant growth at created wetlands. Our study took place at 12 newly created wetlands that were isolated from other wetlands by >5 km. Six wetlands were treated as reference wetlands, with no introductions of seeds or propagules. At the other six wetlands we spread ≈10–15 cm of salvaged soil from a donor wetland during the winter of 1999–2000. To identify the potential plants in donor soil, we collected 10 random samples from the donor wetlands and placed them within wetland microcosms in a greenhouse where they were treated to either moist-soil conditions (water at or just below the soil line) or submersed conditions (water levels maintained at 15–30 cm). Treatment wetlands were evaluated for plant growth during the fall of 2000 and 2001, whereas the greenhouse samples were grown for two growing seasons then harvested. Our results show that using salvaged wetland soil increases: (1) the number of plant species present at a wetland over time, (2) the total vegetation coverage in a treated wetland over time, and (3) the total plant biomass in a treated wetland. The species pool available in the salvaged wetland soil was limited to 10 obligate wetland species, but several of them are considered valuable to waterfowl and other wildlife. Furthermore, salvaged-wetland soil could be useful for ameliorating poor substrate conditions (i.e., bentonite) and improving conditions for the establishment of additional species. One concern with this technique is the introduction of invasive or exotic species that could form monocultures of undesirable plants (e.g., cattail [Typha spp.]); introducing more desirable species during the application of salvaged soil could reduce this probability. We believe incorporating salvaged-wetland soil during basin construction could be used to increase the value and productivity of created wetlands in this region.     

Cytotoxicity and mechanical behavior of chitin-bentonite clay based polyurethane bio-nanocomposites

Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite^® HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4′-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000 g/mol⁻¹). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2 moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS^® bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS^® bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS^® bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties.     

用皂土法制造型特异性肉毒诊断血清

用皂土为载体与类毒素结合方法及破伤风类毒素抗原抗体絮状反应方法去除A、B、C、D、E、F型肉毒抗血清原料中的异型和异种抗毒素(破伤风抗毒素)。制备的A、B、C、D、E、F型肉毒诊断血清每1m l均能中和相应型的肉毒毒素10000LD50以上,而中和异型肉毒毒素或破伤风毒素均低于5 LD50;A、B、C、D、E、F各型混合后的混合型血清每1m l能中和各型肉毒毒素亦大于10000 LD50,中和破伤风毒素低于5 LD50,即效价和特异性符合规程要求。     

The influence of mineral amendments on the changes in the organic nitrogen components of composts

Summary A series of straw composts, containing two levels of ammonium nitrate, were incubated with mineral amendments. Rate of decomposition was at a maximum over the first twenty days and was not influenced by the level of added nitrogne. The presence of bentonite and kaolinite reduced the loss of organic material slightly over the period of 150 days. In the low-N series, all the added inorganic nitrogen was immediately immobilized but in the high-N series inorganic N was slightly in excess of the microorganisms requirements. Little or no remineralization occurred. As a result of immobilization there was a rapid increase in amino acid and amino sugar nitrogen over the first 30 days and the values then remained fairly constant. The amino acid and amino sugar levels were slightly higher in the composts containing bentonite and kaolinite.In the early stages of the composting process, approximately half the organic nitrogen was soluble in phosphate buffer but the amount decreased with time of composting. Similarly, the amount of extracted nitrogen which could be hydrolysed by proteolytic enzymes, decreased with time. The composition of amino sugars liberated by acid hydrolysis suggested that chitin, probably of fungal origin, accounted for much of the amino sugar nitrogen and there is some evidence from oxidation studies for this. As composting proceeded, the amount of galactosamine increased and eventually muramic acid was identified indicating an increase in the bacterial flora.     

Toxicity of cadmium to twoStreptomyces species as affected by clay minerals

Summary The effect of cadmium on the growth ofStreptomyces rimosus andS. bottropensis (both isolated from soil) was investigated. The modifying effect of the presence of the clay minerals kaolinite, bentonite and vermiculte on Cd toxicity was also included. After four days no growth was observed at 100 ppm CdCl₂ ofS. bottropensis and at 150 ppm in case ofS. rimosus. After six days some growth ofS. rimosus occurred at 150 ppm CdCl₂ and ofS. bottropensis at 100 ppm. Addition of the three clay minerals decreased the Cd toxicity considerably.     

Production,characterization and (co-)immobilization of dextranase from <Emphasis Type="Italic">Penicillium aculeatum</Emphasis>

Fermentation kinetics of Penicillium aculeatum ATCC 10409 demonstrated that fungal growth and dextranase release are decoupled. Inoculation by conidia or mycelia resulted in identical kinetics. Two new isoenzymes of the dextranase were characterized regarding their kinetic constants, pI, MW, activation energy and stabilities. The larger enzyme was 3-fold more active (turnover number: 2,230 ± 97 s⁻¹). Pre-treatment of bentonite with H₂O₂ did not affect adsorption characteristics of dextranase. Enzyme to bentonite ratios above 0.5:1 (w/w) resulted in a high conservation of activity upon adsorption. Furthermore, dextranase could be used in co-immobilizates for the direct conversion of sucrose into isomalto-oligosaccharides (e.g. isomaltose). Yields of co-immobilizates were 2–20 times that of basic immobilizates, which consist of dextransucrase without dextranase.     

Free Swell Characteristics of PCC Bottom Ash-Bentonite Mixtures with Curing for Use as Fill or Liner Material

Bottom ash is a coal combustion product (CCP) obtained from burning of pulverized coal to produce electricity. Most of the bottom ash from pulverized coal combustion (PCC) plants is disposed of in landfills and/or ash ponds. Over the last decade, there has been increased attention aimed toward the use of PCC bottom ash in geotechnical applications. The particle size distribution of pulverized coal combustion (PCC) bottom ash is similar to that of natural sand. Natural sand is commonly used in the construction industry in place of cohesive soils by adding admixtures to amend its properties. Several studies have been completed to determine the properties of bottom ash amended with bentonite. However, due to significant volume change characteristics of bentonite, soils or similar granular materials amended with it need to be evaluated for their swelling behavior. In addition, studies on bottom ash-bentonite mixtures have shown that strength and stiffness characteristics of these mixtures change significantly with curing. Therefore, in order to evaluate the use of bottom ash as a fill or landfill liner material, this study was initiated to investigate the effect of curing and moisture content on the swelling characteristics of pulverized coal combustion bottom ash amended with bentonite. Bottom ash specimens containing 15 and 20 percent bentonite and prepared at 14, 16 and 18 percent initial moisture content were tested in this investigation. Results presented show the swelling characteristics of bottom ash-bentonite mixtures with curing age up to 60 days.     

A novel approach for removing an industrial dye 4GL by an Algerian Bentonite

Adsorption processes of 4GL on two different bentonite-based sorbents were compared: i) Sodium-bentonite in the presence of a cationic surfactant CTAMB; ii) organobentonite alone. This latter was prepared by exchanging the inorganic cation of bentonite with a quaternary ammonium cation at 100% of the clay's CEC. Batch adsorption studies were conducted to evaluate the effect of various parameters such as the quaternary ammonium cation (CTAMB) loading, contact time and initial 4GL concentration.From the kinetic study, it is interesting to note that Organobentonite exhibits faster kinetics compared to Na-bentonite/CTAMB system. The comparison between isotherm plots makes clear that the presence of CTAMB in solution changes the 4GL isotherm. Compared to organobentonite, the adsorption capacity is higher when CTAMB was present in solution. In this case, the results of 4GL adsorption by bentonite obey to Langmuir model. While for organobentonite, all models seem to be applicable. The difference between the two methods is confirmed by XRD analysis.The performance shown by Organobentonite and Na-bentonite/CTAMB system was suitable compared to other adsorbents, reflecting a promising future utilization in wastewater treatment.     

Trunk implanted zinc-bentonite as a source of zinc for apple trees

Summary The feasibility of zinc supply to apples (Malus spp. var. Golden Delicious) by various Zn-bentonite preparations implanted in the trunk was studied. A preliminary experiment included four preparations and was conducted in one plantation in 1980. A larger scale experiment in 1981, tested Zn-bentonite (ZnB) and Zn-bentonite + ZnEDTA (ZnBEA) in four plantations in the south, center and north of Israel. Clay tablets were implanted in holes drilled in the tree trunk in April. The youngest, fully developed leaves on the new growth were sampled periodically and Zn content was determined.ZnB and ZnBEA implanted at the rate of 15 mg Zn/cm trunk circumference significantly increased Zn content above that of the control trees until mid-September. The ZnBEA preparation supported significantly higher leaf concentrations than the ZnB preparation. Peak concentrations in trees treated with the ZnBEA preparation were 75.8, 47.4, 38.4, and 23.7 ppm in the four plantations and occurred in May. The Zn concentration in the youngest leaves decreased during the season but there was evidence that in some cases Zn behaved as a phloem mobile element. Soil, climate and previous zinc treatments affected considerably the Zn concentration found in leaves in the four plantations making it impossible to identify a single critical concentration level.No damage to the trees was observed as a result of the drilling and implantation of the clay tablets. Clay analysis at the end of the season showed that about two-thirds of the Zn added to the trees was used. The amount of Zn supplied per tree in the implantation procedure was 80–90% lower than that supplied in the routine spraying operations.