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Lubricant and diesel oil-polluted sites are difficult to remediate because they have less volatile and biodegradable characteristics. The goal of this research was to evaluate the potential of applying an enhanced landfarming to bioremediate soils polluted by lubricant and diesel. Microcosm study was performed to evaluate the optimal treatment conditions with the addition of different additives (nutrients, addition of activated sludge from oil-refining wastewater facility, compost, TPH-degrading bacteria, and fern chips) to enhance total petroleum hydrocarbon (TPH) removal. To simulate the aerobic landfarming biosystem, air in the microcosm headspace was replaced once a week. Results demonstrate that the additives of activated sludge and compost could result in the increase in soil microbial populations and raise TPH degradation efficiency (up to 83% of TPH removal with 175 days of incubation) with initial (TPH = 4100 mg/kg). The first-order TPH degradation rate reached 0.01 1/d in microcosms with additive of activated sludge (mass ratio of soil to inocula = 50:1). The soil microbial communities were determined by nucleotide sequence analyses and 16S rRNA-based denatured gradient gel electrophoresis. Thirty-four specific TPH-degrading bacteria were detected in microcosm soils. Chromatograph analyses demonstrate that resolved peaks were more biodegradable than unresolved complex mixture. Results indicate that more aggressive remedial measures are required to enhance the TPH biodegradation, which included the increase of (1) microbial population or TPH-degrading bacteria, (2) biodegradable carbon sources, (3) nutrient content, and (4) soil permeability.

Summary Certain vertebrates such as salamanders and zebrafish are able to regenerate complex tissues (e.g., limbs and fins) with remarkable fidelity. However, how positional information of the missing structure is recalled by appendage stump cells has puzzled researchers for centuries. Here, we report that sizing information for adult zebrafish tailfins is encoded within proliferating blastema cells during a critical period of regeneration. Using a chemical mutagenesis screen, we identified a temperature-sensitive allele of the gene encoding DNA polymerase alpha subunit 2 (pola2) that disrupts fin regeneration in zebrafish. Temperature shift assays revealed a 48-h window of regeneration, during which positional identities could be disrupted in pola2 mutants, leading to regeneration of miniaturized appendages. These fins retained memory of the new size in subsequent rounds of amputation and regeneration. Similar effects were observed upon transient genetic or pharmacological disruption of progenitor cell proliferation after plucking of zebrafish scales or head or tail amputation in amphioxus and annelids. Our results provide evidence that positional information in regenerating tissues is not hardwired but malleable, based on regulatory mechanisms that appear to be evolutionarily conserved across distantly related phyla.

Clonal complex 59 (CC59) Staphylococcus aureus in Taiwan includes both methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). As the most prominent community-associated MRSA (CA-MRSA) in Taiwan, CC59 has two major clones characterized as PVL-negative SCCmec IV (carrying the staphylococcal cassette chromosome mec IV but Panton-Valentine leukocidin-negative) and PVL-positive SCCmec V (5C2&5). We investigated the drug resistance, phylogeny and the distribution and sequence variation of SCCmec, staphylococcal bacteriophage φSA3, genomic island νSaβ and MES (an enterococcal mobile genetic element conferring multidrug resistance) in 195 CC59 S. aureus. Sequencing and PCR mapping revealed that all of the CC59/SCCmec V (5C2&5) MRSA strains had acquired MESPM1 or its segregants, and obtained a φSA3-related fragment in νSaβ. In contrast, MES6272-2 and MES4578, which showed gentamicin resistance that was not encoded by MESPM1, were dominant in SCCmec IVg MRSA. Translocation of a whole φSA3 into νSaβ instead of only a φSA3-related fragment was common in SCCmec IVg MRSA. However, the non-subtype-g SCCmec IV MRSA (SCCmec IVa is the major) still carried MES and νSaβ structures similar to those in SCCmec V (5C2&5) MRSA. A minimum spanning tree constructed by multiple-locus variable-number tandem repeat analysis revealed that SCCmec IVg MRSA and SCCmec V (5C2&5) MRSA grouped respectively in two major clades. The CC59 MSSA was equally distributed among the two clades, while the non-subtype-g SCCmec IV MRSA mostly clustered with SCCmec V (5C2&5) MRSA. Our findings strongly suggest that CC59 MSSA acquired divergent mobile genetic elements and evolved to SCCmec IVg MRSA and SCCmec V (5C2&5) MRSA/non-subtype-g SCCmec IV MRSA independently. The evolutionary history of CC59 S. aureus explains how mobile genetic elements increase the antimicrobial resistance and virulence and contribute to the success of CA-MRSA in Taiwan.

Air sparging is a remedial method for groundwater. The remedial region is similar to the air flow region in the saturated zone. If soil particles are transported during air sparging, the porosity distributions in the saturated zone change, which may alter the flow path of the air. To understand better the particle movement, this study performed a sandbox test to estimate the soil porosity change during air sparging. A clear fracture was formed and the phenomenon of particle movement was observed when the air injection was started. The moved sand filled the porous around the fracture and the reparked sand filled the fracture, reducing the porosity around the fracture. The results obtained from the photographs of the sandbox, the current measurements and the direct sand sample measurements were close to each other and are credible. Therefore, air injection during air sparging causes sand particle movement of sand, altering the characteristic of the sand matrix and the air distribution.