Effects of treatment processes on AOC removal and changes of bacterial diversity in a water treatment plant.

The effectiveness of different treatment processes on assimilable organic carbon (AOC) removal and bacterial diversity variations was evaluated in a water treatment plant. The van der Kooij technique was applied for AOC analysis and responses of bacterial communities were characterized by the metagenomics assay. Results show that the AOC concentrations were about 93, 148, 43, 51, 37, and 38 µg acetate-C/L in effluents of raw water basin, preozonation, rapid sand filtration (RSF), ozonation, biofiltration [biological activated carbon (BAC) filtration], and chlorination (clear water), respectively. Increased AOC concentrations were observed after preozonation, ozonation, and chlorination units due to the production of biodegradable organic matters after the oxidation processes. Results indicate that the oxidation processes were the main causes of AOC formation, which resulted in significant increases in AOC concentrations (18-59% increment). The AOC removal efficiencies were 47, 28, and 60% in the RSF, biofiltration, and the whole system, respectively. RSF and biofiltration were responsible for the AOC treatment and both processes played key roles in AOC removal. Thus, both RSF and biofiltration processes would contribute to AOC treatment after oxidation. Sediments from the raw water basin and filter samples from RSF and BAC units were collected and analyzed for bacterial communities. Results from scanning electron microscope analysis indicate that bacterial colonization was observed in filter materials. This indicates that the surfaces of the filter materials were beneficial to bacterial growth and AOC removal via the adsorption and biodegradation mechanisms. Next generation sequencing analyses demonstrate that water treatment processes resulted in the changes of bacterial diversity and community profiles in filters of RSF and BAC. According to the findings of bacterial composition and interactions, the dominant bacterial phyla were Proteobacteria (41% in RSF and 56% in BAC) followed by Planctomycetes and Acidobacteria in RSF and BAC systems, which might affect the AOC biodegradation efficiency. Results would be useful in developing AOC treatment and management processes in water treatment plants.

Developing an Integrated Modeling Tool for River Water Quality Index Assessment.

The goal of this study was to establish a modeling tool for river water quality with a direct linkage to the water quality index (WQI5) calculation and the river water quality model, the Water Quality Analysis Simulation Program (WASP), for pollutant transport modeling. The integrated WASP and WQI5 tool was field-tested to assess pollutant loadings and their impacts on river environment. Suspended solid (SS) and electric conductivity (EC) correlation equations and the WQI5 calculation tool were included in the water quality model and direct WQI5 calculation. The SS concentration, which was influenced by river flows, had crucial effects on river water quality and WQI5 values. EC value was controlled by dissolution of soil minerals, which was affected by the watershed drainage area and surface runoff. The integrated system could establish a direct correlation for river water quality, river flow, and WQI5.

Dissemination of meticillin-resistant Staphylococcus aureus sequence type 8 (USA300) in Taiwan.

BACKGROUND: In Taiwan, sequence type (ST) 239 and ST59 were two major clones among meticillin-resistant Staphylococcus aureus (MRSA) clinical isolates in the past two decades. USA300 (ST8) prevailed in the Americas but not in outside areas. Recently USA300 (ST8) emerged and was increasingly identified in Taiwan; we thus conducted an island-wide study to explore the role of USA300 among MRSA isolates. METHODS: One hundred MRSA bloodstream isolates identified in 2020 from each of the six participating hospitals in Taiwan were collected and characterized. The first 10 ST8 isolates from each hospital were further analysed by whole-genome sequencing. RESULTS: Of the 590 confirmed MRSA isolates, a total of 22 pulsotypes and 21 STs were identified. The strain of pulsotype AI/ST8 was the most common lineage identified, accounting for 187 isolates (31.7%) and dominating in five of six hospitals, followed by pulsotype A/ST239 (14.7%), pulsotype C/ST59 (13.9%) and pulsotype D/ST59 (9.2%). Of the 187 pulsotype AI/ST8 isolates, 184 isolates were characterized as USA300 and clustered in three major sub-pulsotypes, accounting for 78%. Ninety per cent of the 60 ST8 isolates for whole-genome sequencing were clustered in three major clades. CONCLUSIONS: In 2020, USA300 became the most common clone of MRSA in Taiwan, accounting for >30% of MRSA bloodstream isolates island wide. Most of USA300 isolates circulating in Taiwan might have been imported on multiple occasions and evolved into at least three successful local clades. MRSA USA300 has successfully established its role in Taiwan, an area outside of the Americas.

Nanostructured silicon surface modifications for as a selective matrix-free laser desorption/ionization mass spectrometry.

Matrix-assisted laser desorption/ionization mass spectrometry is an established soft ionization method that is widely applied to analyze biomolecules. The UV-absorbing organic matrix is essential for biomolecule ionization; however, it also creates matrix background interference, which results in problematic analyses of biomolecules of less than 700 Da. Therefore, this study investigates hydrophilic, hydrophobic cationic, anionic and immobilized metal ion surface chemical modifications to advance nanostructured silicon mass spectrometry performance (nSi-MS). This investigation provides information required for a possible novel mass spectroscopy that combines surface-enhanced and nanostructured silicon surface-assisted laser desorption/ionization mass spectrometry for the selective detection of specific compounds of a mixture.

X-ray microscopy and tomography detect the accumulation of bare and PEG-coated gold nanoparticles in normal and tumor mouse tissues.

We demonstrate that, with appropriate staining, high-resolution X-ray microscopy can image complicated tissue structures--cerebellum and liver--and resolve large or small amounts of Au nanoparticles in these tissues. Specifically, images of tumor tissue reveal high concentrations of accumulated Au nanoparticles. PEG (poly(ethylene glycol)) coating is quite effective in enhancing this accumulation and significantly modifies the mechanism of uptake by reticuloendothelial system (RES) organs.

Investigation of genetic relationships among Taiwan black pigs and other pig breeds in Taiwan based on microsatellite markers.

The aim of this study was to investigate the genetic relationships between Taiwan black pigs (TBP) and other pig breeds by means of 15 fluorescent-labeled microsatellite markers. DNA from a total of 299 TBP from eight private farms and 234 purebred pigs representing six breeds and one synthetic line was used. Among the 15 microsatellite loci, polymorphism information content (PIC) values were all above 0.500; the numbers of observed alleles were all greater than the numbers of effective alleles (10.1 vs. 4.3 in averages). But 13 of the 15 microsatellite markers significantly deviated from the Hardy-Weinberg equilibrium (HWE); moreover, 13 of the 15 tested populations also deviated from the HWE. The inbreeding coefficient (F(IS)) indicated that two TBP populations (TBP-3 and TBP-4) had heterozygote deficiency (P < 0.01). The pair-wise F(ST), representing the genetic diversity between the two populations, ranged from 0.0332 to 0.3809. Meishan and Taoyuan breeds with black hair were previously considered closely related to TBP; however, the result of genetic relationship refuted this assumption. In conclusion, TBP is more similar to the European than Chinese breeds, and further investigations will need to clarify it more accurately.

Functional cis-expression of phaCAB genes for poly(3-hydroxybutyrate) production by Escherichia coli.

AIMS: To develop a microbial strain producing poly(3-hydroxybutyrate) [P(3HB)], in the absence of antibiotic supplementation (normally required to stabilize a recombinant plasmid), by constructing a recombinant Escherichia coli strain with phaCAB and vgb integrated into the chromosome. METHODS AND RESULTS: The polyhydroxyalkanoate (PHA) synthesis operon (phaCAB) and the bacterial haemoglobin gene (vgb) were integrated downstream of nlpB (novel lipoprotein B) in E. coli K12, via homologous recombination, to form a recombinant strain, termed YH100. VHb encoded by the vgb gene was successfully expressed in YH100, as confirmed by Western blotting. P(3HB) synthesis by the YH100 strain grown in the absence of antibiotic was analysed by transmission electron microscopy. The yield of P(3HB) is 208 mg g(-1) . The thermal stability of P(3HB) produced from YH100 was similar to that of commercial P(3HB). Further, the polydispersity index (PDI) of the P(3HB) polymer derived from YH100 was 1·37, indicating that polymer uniformity was greater than that of commercial P(3HB), which had a PDI of 1·47. CONCLUSIONS: We successfully constructed a recombinant E. coli strain expressing exogenous genes, specifically phaCAB from Cupriavidus necator and vgb from Vitreoscilla stercoraria, integrated into the downstream of chromosomal dapA-nlpB locus. P(3HB) was stably produced by this strain, without any need for antibiotic supplementation to stabilize a recombinant plasmid at least for 48h. SIGNIFICANCE AND IMPACT OF THE STUDY: We report a genetic locus, the downstream of the nlpB locus in E. coli, in which the transcription of the exogenous genes is driven by the dapA-nlpB promoter without the need for the addition of inducer and antibiotic.

Idiotypes of inulin-binding myeloma proteins localized to variable region light and heavy chains: genetic significance.

Idiotypes of inulin-binding myeloma proteins (InuBMP) were determined primarly by variable region light chains (VL) or by variable region heavy chains (VH) but needed both chains to be expressed. Recombinant molecules were used to show that individual idiotypes (IdI) of U61, E109, T957, and A4 InuBMP and cross-specific idiotypes (IdXB) of U61 were primarily determined by VL while cross-specific idiotype (IdXA) of A4 was determined mainly by VH. The assignment of genes controlling idiotypes to VH based on allotype linkage (e.g., IdXB) is dubious until the role of the L chain in determining that idiotype is assessed. IdXB has been shown to be a VL-VH marker which presumably is controlled by two unlinked genes. However IdXB can be used as a L chain marker in combinations of strains differing in their L chain genes but having the same permissive H chain genes. Conversely IdXB can be used as a H chain marker in strains having the same permissive L chain genes but differing in their H chain genes.

Regulation of the anti-inulin antibody response by a nonallotype-linked gene.

The antibody response to the inulin [(In), beta-(2 leads to 1) fructosan] determinant of bacterial levan [(BL), a beta-(2 leads to 6) polyfructosan that contains beta-(2 leads to 1) branch points] requires the presence of the a haplotype of the Igh gene complex. BALB/c (Igh a) mice immunized with BL produce IgG anti-In antibodies of a single spectrotype by isoelectric focusing analysis. C57BL/6 mice, which possess the b haplotype of the Igh gene complex and which fail to produce anti-In antibodies, nevertheless possess a gene, spectrotype regulation gene 1 (Sr-1), that regulates the isoelectric focusing (IEF) pattern of anti-In antibodies in mice of the a haplotype. Thus, the IEF patterns of anti-In antibodies of (BALB/c x C57BL/6)F1 mice and of B.C8 mice (C57BL/Ka . Igh-Ca) are considerably more complex than those of BALB/c. Backcross analysis indicates that Sr-1 is not linked to the Igh complex, the major histocompatibility complex, or to the genes that code for coat color. Studies of the heterogeneity of anti-In antibodies in recombinant inbred lines and their progeny from matings to BALB/c and C.B20 (BALB/c . Igh-Cb) suggest the existence of other regulatory genes.

Zero-bias anomalies in narrow tunnel junctions in the quantum Hall regime.

We report on the study of cleaved-edge-overgrown line junctions with a serendipitously created narrow opening in an otherwise thin, precise line barrier. Two sets of zero-bias anomalies are observed with an enhanced conductance for filling factors ν>1 and a strongly suppressed conductance for ν<1. A transition between the two behaviors is found near ν≈1. The zero-bias anomaly (ZBA) line shapes find explanation in Luttinger liquid models of tunneling between quantum Hall edge states. The ZBA for ν<1 occurs from strong backscattering induced by suppression of quasiparticle tunneling between the edge channels for the n=0 Landau levels. The ZBA for ν>1 arises from weak tunneling of quasiparticles between the n=1 edge channels.

Enhanced polyhydroxybutyrate (PHB) production via the coexpressed phaCAB and vgb genes controlled by arabinose P promoter in Escherichia coli.

AIM: To develop an approach to enhance polyhydroxybutyrate (PHB) production via the coexpressed phaCAB and vgb genes controlled by arabinose P(BAD) promoter in Escherichia coli. METHOD AND RESULTS: The polyhydroxyalkanoates (PHAs) synthesis operon, (phaCAB), from Ralstonia eutropha was overexpressed under the regulation of the arabinose P(BAD) promoter in Escherichia coli, and the vgb gene encoding bacterial haemoglobin from Vitreoscilla stercoraria (VHb) was further cloned at downstream of phaCAB to form an artificial operon. The cell dry weight (CDW), PHB content and PHB concentration were enhanced around 1.23-, 1.57-, and 1.93-fold in the engineered cell harbouring phaCAB-vgb (SY-2) upon 1% arabinose induction compared with noninduction (0% arabinose). Furthermore, by using a recombinant strain harbouring P(BAD) promoter-vgb along with native promoter-phaCAB construction, the effect of vgb expression level on PHB biosynthesis was positive correlation. CONCLUSIONS: The results exploit the possibility to improve the PHB production by fusing the genes phaCAB-vgb from different species under the arabinose regulation system in E. coli. It also demonstrates that increase in VHb level enhances the PHB production. SIGNIFICANCE AND IMPACT OF THE STUDY: We were successful in providing a new coexpressed system for PHB synthesis in E. coli. This coexpressed system could be regulated by arabinose inducer, and is more stable and cheaper than other induced systems (e.g. IPTG). Furthermore, it could be applied in many biotechnology or fermentation processes.

Meperidine-induced serotonin syndrome in a susceptible patient.

We present a patient with a history of clomipramine-induced serotonin syndrome 5 yr prior who developed serotonin syndrome after a single dose of meperidine. This report heightens appreciation of population at risk and also recognition of potential toxicity in meperidine.

Evaluation of biological stability and corrosion potential in drinking water distribution systems: a case study.

The appearance of assimilable organic carbon (AOC), microbial regrowth, disinfection by-products (DBPs), and pipe corrosion in drinking water distribution systems are among those major safe drinking water issues in many countries. The water distribution system of Cheng-Ching Lake Water Treatment Plant (CCLWTP) was selected in this study to evaluate the: (1) fate and transport of AOC, DBPs [e.g., trihalomethanes (THMs), haloacetic acids (HAAs)], and other organic carbon indicators in the selected distribution system, (2) correlations between AOC (or DBPs) and major water quality parameters [e.g. dissolved oxygen (DO), free residual chlorine, and bacteria, and (3) causes and significance of corrosion problems of the water pipes in this system. In this study, seasonal water samples were collected from 13 representative locations in the distribution system for analyses of AOC, DBPs, and other water quality indicators. Results indicate that residual free chlorine concentrations in the distribution system met the drinking water standards (0.2 to 1 mg l(-1)) established by Taiwan Environmental Protection Administration (TEPA). Results show that AOC measurements correlated positively with total organic carbon (TOC) and UV-254 (an organic indicator) values in this system. Moreover, AOC concentrations at some locations were higher than the 50 microg acetate-C l(-1) standard established by Taiwan Water Company. This indicates that the microbial regrowth might be a potential water quality problem in this system. Higher DO measurements (>5.7 mg l(-1)) might cause the aerobic biodegradation of THMs and HAAs in the system, and thus, low THMs (<0.035 mg l(-1)) and HAAs (<0.019 mg l(-1)) concentrations were observed at all sampling locations. Results from the observed negative Langelier Saturation Index (LSI) values, higher Ryznar Stability Index (RSI) values, and high Fe3+ concentrations at some pipe-end locations indicate that highly oxidative and corrosive conditions occurred. This reveals that pipe replacement should be considered at these locations. These findings would be helpful in managing the water distribution system for maintaining a safe drinking water quality.

Selective loss of delta opioid analgesia and binding by antisense oligodeoxynucleotides to a delta opioid receptor.

Antisense oligodeoxynucleotides (18-20 bases) to a cloned delta opioid receptor (DOR-1) lower delta binding in NG108-15 cells by 40%-50%. Changing 4 bases to generate a mismatch antisense oligodeoxynucleotide or mixing the corresponding sense and antisense oligodeoxynucleotides prior to treatment of the cells eliminates the inhibition of binding, confirming the specificity of the response. In vivo, an antisense oligodeoxynucleotide to DOR-1 given intrathecally lowers delta, but not mu or kappa 1 spinal analgesia. The mismatch antisense oligodeoxynucleotide is inactive. Delta analgesic sensitivity gradually returns by 5 days after the last antisense treatment, indicating the lack of irreversible damage or toxicity. These studies demonstrate that DOR-1 mediates delta analgesia at the level of the spinal cord and confirm at the molecular level traditional pharmacological studies implying distinct receptor mechanisms for delta, mu, and kappa 1 analgesia. The use of antisense approaches may prove valuable in understanding the receptors mediating opioid pharmacology.

Polyhydroxyalkanoates production from carbohydrates by a genetic recombinant Aeromonas sp.

AIMS: To develop an Aeromonas strain able to utilize inexpensive carbon sources such as starch for the synthesis of polyhydroxyalkanoates (PHA). METHODS AND RESULTS: A recombinant Aeromonas sp. (strain KC007-1) was constructed by introducing the PHB synthesis genes (phaCAB) into the bacterium. Strain KC001-R1 can not only use carbohydrate (including starch) for growth but also accumulate significant amounts of polyhydroxybutyrate (PHB) in the cells. CONCLUSIONS: One of the present focuses on PHA production has been on lowering the production costs. Starch is an example of an inexpensive carbohydrate for use in industrial production of PHA. We have demonstrated that by introducing the phaCAB operon into Aeromonas sp. allowed the bacterium able to accumulated PHB using this substrate. SIGNIFICANCE AND IMPACT OF THE STUDY: Aeromonas spp. are able to synthesize PHA using fatty acids as carbon source. Although good robust growth results with use of starch as sole carbon source for Aeromonas, PHA synthesis does not occur. Strain KC007-R1 showed the ability to accumulate PHA in relative high amount with both carbohydrates and fatty acids as carbon source, and can be cultivated to a significant amount of cell mass and hence is a potential strain for further development for industrial applications.

Application of biofiltration system on AOC removal: column and field studies.

The Cheng-Ching Lake Water Treatment Plant (CCLWTP) is the main supplier of domestic water for the Greater Kaohsiung area, the second largest metropolis in Taiwan. Biological activated carbon (BAC) filtration is one of the major treatment processes in CCLWTP. The objectives of this study were to evaluate the effectiveness of BAC filtration on water treatment in the studied advanced water treatment plant and its capability on pollutants [e.g., AOC (assimilable organic carbon), bromide, bromate, iron] removal. In this study, water samples from each treatment process of CCLWTP were collected and analyzed periodically to assess the variations in concentrations of AOC and other water quality indicators after each treatment unit. Moreover, the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers was also evaluated through a column experiment. Results show that the removal efficiencies for AOC, bromide, bromate, and iron are 86% 100%, 17%, and 30% after the BAC filter bed, respectively. This indicates that BAC filtration plays an important role in pollutant removal. Results also show that AOC concentrations in raw water and effluent of the CCLWTP are approximately 143 and 16 microg acetate-Cl(-1), respectively. This reveals that the treatment processes applied in CCLWTP is able to remove AOC effectively. Results of column study show that the AOC removal efficiencies in the GAC and anthracite columns are 60% and 17%, respectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic images. The observed microorganisms included bacteria (rods, cocci, and filamentous bacteria), fungi, and protozoa. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.

Development of a two-stage biotransformation system for mercury-contaminated soil remediation.

Utilization of bacterial volatilization can be problematic to remediate mercury (Hg)-contaminated soils because most of the Hg in soils is bound to soil particles. The objective of this study was to develop a two-stage system (chemical extraction followed by microbial reduction) for Hg-contaminated soil remediation. The tasks were to (1) select the extraction reagents for Hg extraction, (2) assess the effects of extraction reagents on the growth of Hg-reducing bacterial strains, and (3) evaluate the effectiveness of Ca2+ and Mg2+ addition on merA gene (Hg reductase) induction. Bacterial inhibition was observed with the addition of 0.1 M ethylenediaminetetraacetic acid or citric acid. Up to 65% of Hg was biotransformed (Hg concentration = 69 mg/kg) from the soils after a 24 h extraction using 0.5 M ammonium thiosulfate. Ca2+ and Mg2+ were selected because they have the same electric charge as Hg and the studied groundwater contained high concentrations of Ca2+ and Mg2+. Results showed that the addition of 200 mg/L Ca2+ or 650 mg/L Mg2+ could reach effective merA induction. In the two-stage experiment, 120 mg/kg Hg-contaminated soils were extracted with 2 rounds of extraction processes for 10 h using 0.5 M ammonium thiosulfate. Approximately 77% of Hg was extracted from the soils after the first-step extraction process. Up to 81% of Hg2+ was transformed from the washing solution via the biotransformation processes with Enterobacter cloacae addition and Ca2+ and Mg2+ supplementation. The two-stage remedial system has the potential to be developed into a practical technology to remediate Hg-contaminated sites.

Adult Pseudomonas aeruginosa meningitis: high incidence of underlying medical and/or postneurosurgical conditions and high mortality rate.

We analyzed the clinical and laboratory characteristics, therapeutic outcome and prognostic factors of 25 cases of cerebrospinal fluid (CSF) culture-proven Pseudomonas aeruginosa adult bacterial meningitis (ABM). Twelve P. aeruginosa strains, isolated from clinical CSF specimens, were tested for antibiotic susceptibility. The 25 cases included 17 men and 8 women, aged 17 to 86 years (median=51). Of the 25 cases of P. aeruginosa ABM, 18 were the result of postneurosurgical infection and the other 7 were spontaneous infections. The latter 7 cases had serious underlying medical conditions. The antibiotic susceptibility rates of the 12 strains were as follows: ceftriaxone 16.7% (2/12), ceftazidime 91.7% (11/12), cefepime 83.3% (10/12), imipenem 83.3% (10/12), meropenem 83.3% (10/12) and ciprofloxacin 66.7% (8/12). The therapeutic results showed an overall mortality rate of 40% (10/25). The emergence of third-generation cephalosporin-resistant P. aeruginosa strains cultured from clinical CSF specimens in recent years has resulted in a therapeutic challenge in the treatment of ABM.

αTAT1 downregulation induces mitotic catastrophe in HeLa and A549 cells.

α-Tubulin acetyltransferase 1 (αTAT1) controls reversible acetylation on Lys40 of α-tubulin and modulates multiple cellular functions. αTAT1 depletion induced morphological defects of touch receptor neurons in Caenorhabditis elegans and impaired cell adhesion and contact inhibition in mouse embryonic fibroblasts, however, no morphological or proliferation defects in human RPE-hTERT cells were found after αTAT1-specific siRNA treatment. Here, we compared the effect of three αTAT1-specific shRNAs on proliferation and morphology in two human cell lines, HeLa and A549. The more efficient two shRNAs induced mitotic catastrophe in both cell lines and the most efficient one also decreased F-actin and focal adhesions. Further analysis revealed that αTAT1 downregulation increased γ-H2AX, but not other DNA damage markers p-CHK1 and p-CHK2, along with marginal change in microtubule outgrowth speed and inter-kinetochore distance. Overexpression of αTAT1 could not precisely mimic the distribution and concentration of endogenous acetylated α-tubulin (Ac-Tu), although no overt phenotype change was observed, meanwhile, this could not completely prevent αTAT1 downregulation-induced deficiencies. We therefore conclude that efficient αTAT1 downregulation could impair actin architecture and induce mitotic catastrophe in HeLa and A549 cells through mechanisms partly independent of Ac-Tu.