Disinfection by-products in Croatian drinking water supplies with special emphasis on the water supply network in the city of Zagreb.

The occurrence of disinfection by-products (DBPs) was investigated in 48 drinking water systems across Croatia. Eleven DBPs were studied: chlorite (ClO2-), chlorate (ClO3-), four trihalomethanes (THMs), and five haloacetic acids (HAAs). Furthermore, an intensive sampling program was conducted in the distribution system in the city of Zagreb where, aside from DBP analyses, natural organic matter (NOM) was characterized using fluorescence spectroscopy. In the drinking waters examined across Croatia, DBP values were found in the range from 0.7 µg/L to 32.8 µg/L for THMs, below LOQ to 17.2 µg/L for HAAs (primarily di- and trichloroacetic acids), below LOQ to 720 µg/L for ClO2- and below LOQ to 431 µg/L for ClO3-. The results obtained showed higher chlorite concentrations in the systems treated with hypochlorite compared to systems treated with chlorine dioxide. DBPs in the Zagreb distribution network were generally low (the average values were below 6 µg/L and 2 µg/L for total THM and total HAA respectively). In contrast to our observations throughout Croatia, dibromoacetic acid (DBAA) was found to be the predominant HAA within Zagreb, most likely due to the degradation of chlorinated carboxylates (di-/tri-chloroacetic) in the network. Characterization of NOM by Parallel Factor Analysis (PARAFAC) fluorescence spectroscopy across the Zagreb network showed distinct temporal variations arising from groundwater inputs, as evident from variable humic-, tyrosine-, and tryptophan-like peaks. Statistical correlations between fluorescence data and DBPs highlight its potential for monitoring the presence of DBPs in distribution networks.

Tools for successful proliferation: diverse strategies of nutrient acquisition by a benthic cyanobacterium.

Freshwater cyanobacterial blooms have increased worldwide, channeling organic carbon into these systems, and threatening animal health through the production of cyanotoxins. Both toxic and nontoxic Microcoleus proliferations usually occur when there are moderate concentrations of dissolved inorganic nitrogen, but when phosphorus is scarce. In order to understand how Microcoleus establishes thick biofilms (or mats) on riverbeds under phosphorus-limiting conditions, we collected Microcoleus-dominated biofilms over a 19-day proliferation event for proteogenomics. A single pair of nitrogen-dependent Microcoleus species were consistently present in relatively high abundance, although each followed a unique metabolic trajectory. Neither possessed anatoxin gene clusters, and only very low concentrations of anatoxins (~2 µg kg-1) were detected, likely originating from rarer Microcoleus species also present. Proteome allocations were dominated by photosynthesizing cyanobacteria and diatoms, and data indicate biomass was actively recycled by Bacteroidetes and Myxococcales. Microcoleus likely acquired nutrients throughout the proliferation event by uptake of nitrate, urea, and inorganic and organic phosphorus. Both species also harbored genes that could be used for inorganic phosphate solubilization with pyrroloquinoline quinone cofactors produced by cohabiting Proteobacteria. Results indicate that Microcoleus are equipped with diverse mechanisms for nitrogen and phosphorus acquisition, enabling them to proliferate and out-compete others in low-phosphorus waters.

DNA barcoding and real-time PCR detection of Bactrocera xanthodes (Tephritidae: Diptera) complex.

Immature fruit fly stages of the family Tephritidae are commonly intercepted on breadfruit from Pacific countries at the New Zealand border but are unable to be identified to the species level using morphological characters. Subsequent molecular identification showed that they belong to Bactrocera xanthodes, which is part of a species complex that includes Bactrocera paraxanthodes, Bactrocera neoxanthodes and an undescribed species. To establish a more reliable molecular identification system for B. xanthodes, a reference database of DNA barcode sequences for the 5'-fragment of COI gene region was constructed for B. xanthodes from Fiji, Samoa and Tonga. To better understand the species complex, B. neoxanthodes from Vanuatu and B. paraxanthodes from New Caledonia were also barcoded. Using the results of this analysis, real-time TaqMan polymerase chain reaction (PCR) assays for the detection of B. xanthodes complex and for the three individual species of the complex were developed and validated. The assay showed high specificity for the target species, with no cross-reaction observed for closely related organisms. Each of the real-time PCR assays is sensitive, detecting the target sequences at concentrations as low as ten copies µl-1 and can be used as either singleplex or multiplex formats. This real-time PCR assay for B. xanthodes has been successfully applied at the borders in New Zealand, leading to the rapid identification of intercepted Tephritidae eggs and larvae. The developed assays will be useful biosecurity tools for rapid detection of species in the B. xanthodes complex worldwide.

Moving beyond descriptions of diversity: clinical and research implications of bacterial imbalance in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is a debilitating disease which affects 5-16% of the general population and involves long-term inflammation of the sinonasal cavity. While microbial involvement in the pathogenesis of CRS has long been suspected, the exact role of microbes remains unclear. Recent application of cultivation-independent, molecular methods has provided much new information, taking advantage of developments in both laboratory- and bioinformatics-based analyses. The aim of this mini-review is to present a variety of available bioinformatics approaches, such as data classification techniques and network analyses, with proven applications in other aspects of human microbiome health and disease research. The uses of molecular techniques in the clinical setting are still in its infancy, but these tools can further our understanding of microbial imbalance during chronic disease and help guide effective patient treatment. The mini-review emphasises ways in which CRS bacterial gene-targeted sequencing data can progress beyond descriptive summaries and toward unlocking the mechanisms by which bacterial communities can be markers for sinus health.

Development and validation of a real-time PCR assay for the glassy-winged sharpshooter Homalodisca vitripennis (Hemiptera: Cicadellidae).

The glassy-winged sharpshooter (Homalodisca vitripennis) is an invasive pest organism, which is found throughout Central America and has recently invaded a few countries in the Pacific Islands. As a carrier of the highly virulent plant pathogenic bacterium Xylella fastidiosa, it is of great economic significance to horticulture and is estimated to cost Californian vineyards over US$100 million per year in control and losses. New Zealand is currently free from this pest, but its recent spread through the Pacific has raised concerns of it establishing in New Zealand, potentially as a result of introduction through human travel. We report here a real-time polymerase chain reaction assay for the rapid identification of H. vitripennis. The assay was extensively validated in silico then optimized and tested against a range of Cicadellidae species, both internationally collected and local to New Zealand. This assay was able to correctly identify H. vitripennis samples, and distinguish between H. vitripennis and close relatives, such as the smoke-tree sharpshooter (Homalodisca liturata) and will be of great benefit to New Zealand biosecurity.

Rapid and accurate identification of Xanthomonas citri subspecies citri by fluorescence in situ hybridization.

Citrus canker is an economically important disease caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc). This organism targets a wide range of citrus plants, including sweet orange, grapefruit, lemon and lime. As Xcc is spread by environmental factors such as wind and rain, it is difficult to control its movement once the disease has established. In order to facilitate monitoring of citrus canker we sought to design a novel diagnostic protocol based on fluorescence in situ hybridization (FISH) for identification of bacterial cells directly from canker pustules without cultivation or DNA extraction. This method was validated for specificity against a range of Xanthomonas species and strains. We show that our assay is extremely rapid (typically requiring between 2 and 3 h), and possesses a similar specificity to existing PCR diagnostic tools. The sensitivity of the assay is comparable to that of an existing PCR-based technique and sufficient for identifying Xcc in symptomatic plant material. The method is easily transferable to diagnosticians without prior experience using FISH. SIGNIFICANCE AND IMPACT OF THE STUDY: Xanthomonas citri subsp. citri (Xcc) is an aggressive and hardy pathogen of citrus plants worldwide. Outbreaks are difficult and costly to contain and the establishment of citrus canker results in restricted trade. In order to extend the existing toolkit for identification of Xcc we developed a novel diagnostic approach based on fluorescence in situ hybridization. Our approach is of comparable specificity and sensitivity to existing methods but can be performed directly on infected tissue making it significantly faster than existing PCRs, and requiring fewer laboratory resources.

A comparison of flux chambers and ambient air sampling to measure gamma-hexachlorocyclohexane volatilisation from canola (Brassica napus) fields.

The insecticide gamma-hexachlorocyclohexane (gamma-HCH) is primarily used in Canada in treatments of canola (Brassica napus) seed. It has been shown that gamma-HCH so applied will volatilise with 12-30% entering the atmosphere within 6 wk after the seed is planted. Both flux chambers and high-volume air samplers were used to measure gamma-HCH volatilisation from a canola field and the results from each method compared. Daily samples were collected from three flux chambers located on the field. gamma-HCH was found in the air of the chambers on the first day after planting. Volatilisation rates were low for the first 7d (40.0 mg ha(-1) wk(-1)) but increased during the second week (143.8 mg ha(-1) wk(-1)). This was consistent with previous studies. Weekly composite air samples, from three heights above the canola field, were used to calculate volatilisation rates from the field. These were 190 mg ha(-1) wk(-1) (week 1) and 420 mg ha(-1) wk(-1) (week 2). Soil temperatures in the open field were warmer than those under the flux chambers and this may have contributed to the higher ambient air measurements.

Atmospheric concentrations and dry and wet deposits of some herbicides currently used on the Canadian Prairies.

High volume air sampling in the Canadian Prairies was used to characterize atmospheric concentrations for 10 herbicides (alachlor, atrazine, ethalfluralin, metolachlor, 2,4-D, dicamba, bromoxynil, MCPA, trifluralin, and triallate) along a 500-km north-south transect. Atmospheric concentration measurements at various altitudes identified that of the six herbicides present in the highest concentrations, triallate was strongly influenced by local sources, while 2,4-D, dicamba, bromoxynil, MCPA and trifluralin were dominated by regional atmospheric transport. Concentrations of the herbicides measured at various altitudes were compared with dry deposition rates measured using a dry/wet deposition sampler and used to calculate deposition velocities V(d). The primary atmospheric transport mechanism for MCPA and bromoxynil was shown to be adsorption to particles dispersed in the atmosphere, with the same mechanism also confirmed for 2,4-D and dicamba, while trifluralin was shown to be transported mainly in the gas phase. This method of calculation indicated that transportation of triallate was influenced by particle adsorption. Weekly maximum atmospheric loadings of the major herbicides present in the Prairies were estimated to range from 73 kg for trifluralin to 541 kg for 2,4-D.

Environmental concentrations of agricultural herbicides in Saskatchewan, Canada: bromoxynil, dicamba, diclofop, MCPA, and trifluralin.

Herbicides are the most commonly used group of agricultural pesticides on the Canadian Prairies and, in 1990, more than 20000 Mg of herbicides were applied in the provinces of Alberta, Saskatchewan, and Manitoba. The present paper reports on environmental concentrations of five herbicides currently used in the prairie region. The herbicides bromoxynil [3,5-dibromo-4-hydroxy-benzonitrile], dicamba [3,6-dichloro-o-anisic acid], diclofop [(RS)-2-[4-(2,4-dichlorophenoxy)-phenoxy]propanoic acid], MCPA [(4-chloro-2-methylphenoxy)acetic acid], and trifluralin [alpha,alpha,alpha-trifluoro-2,6-dinitro-N,N-isopropyl-p-toluidine] were measured in the atmosphere, bulk atmospheric deposits, surface film, and dugout (pond) water at two sites near Regina, Saskatchewan, during 1989 and 1990. All five herbicides were detected in air and surface film and all but trifluralin were detected in the bulk atmospheric deposits and dugout water. Trifluralin was most frequently detected in air (79% of samples) whereas bromoxynil was present in maximum concentration (4.2 ng m(-3)). MCPA was present in maximum levels in bulk atmospheric (wet plus dry) deposits (2350 ng m(-2) d(-1)), surface film (390 ng m(-2)), and dugout water (330 ng L(-1)), whereas dicamba was most frequently detected in surface film (47%) and dugout water (97%). The highest quantities of the herbicides tended to be present during or immediately after the time of regional application.

Uptake of atmospheric mercury by deionized water and aqueous solutions of inorganic salts at acidic, neutral and alkaline pH.

Mercury (Hg) is well known as a toxic environmental pollutant that is among the most highly bioconcentrated trace metals in the human food chain. The atmosphere is one of the most important media for the environmental cycling of mercury, since it not only receives mercury emitted from natural sources such as volcanoes and soil and water surfaces but also from anthropogenic sources such as fossil fuel combustion, mining and metal smelting. Although atmospheric mercury exists in different physical and chemical forms, as much as 90% can occur as elemental vapour Hg0, depending on the geographic location and time of year. Atmospheric mercury can be deposited to aquatic ecosystems through both wet (rain or snow) and dry (vapour adsorption and particulate deposition) processes. The purpose of the present study was to measure, under laboratory conditions, the rate of deposition of gaseous, elemental mercury (Hg0) to deionized water and to solutions of inorganic salt species of varying ionic strengths with a pH range of 2-12. In deionized water the highest deposition rates occurred at both low (pH 2) and high (pH 12). The addition of different species of salt of various concentrations for the most part had only slight effects on the absorption and retention of atmospheric Hg0. The low pH solutions of various salt concentrations and the high pH solutions of high salt concentrations tested in this study generally showed a greater tendency to absorb and retain atmospheric Hg0 than those at a pH closer to neutral.

Environmental concentrations of agricultural herbicides: 2,4-d and triallate.

The herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and triallate [S-2,3,3-trichloroallyl di-isopropyl(thiocarbamate)] are extensively used to control broadleaf and wild oat (respectively) weed infestations in Canadian cereal crops. In 1990, for example, more than 3.8 million kg of 2,4-D and 2.7 million kg of triallate were applied in the three prairie provinces (Alberta, Saskatchewan, and Manitoba). Maximum air concentrations of these two herbicides during the summers of 1989 and 1990 near Regina, Saskatchewan, were 3.90 ng m(-3) (2,4-D) and 60.04 ng m(-3) (triallate). Concentrations of these two herbicides were also measured in bulk atmospheric deposition (wet plus dry) and in farm pond water and associated surface film. Maximum measured levels of 2,4-D were 3550 ng m(-2) d(-1) (bulk deposition), 332 ng m(-2) (surface film), and 290 ng L(-1) (pond water). Maximum levels of triallate were 2300 ng m(-2) d(-1) (bulk deposition), 212 ng m(-2) (surface film), and 500 ng L(-1) (pond water). The highest quantities of the herbicides tended to be found during or immediately after the time of regional application. The movement of the herbicides in the environment will be discussed in relation to the four matrices studied.

Materials selection for a dry atmospheric mercury deposits sampler.

In order to develop a sampler for measuring dry deposition rates for atmospheric mercury, suitable materials are needed that neither adsorb nor release mercury. In this paper, four materials (polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), Teflon and glass) were tested. Each of the materials was placed in a beaker containing mercuric solution under varied conditions for pH, preservative concentration, initial mercuric concentration, temperature, acid type and contact time of the material. The concentrations of the mercuric solutions were determined using the cold-vapor atomic absorption (CVAA) technique. The experimental results show that glass has the lowest absolute net adsorption rates (NARs) of 0.026-1.13 pg/m2 among the materials tested. Teflon, PVC and ABS have NARs ranging from 0.54 to 10.4 microg/M2 over an adsorption duration of one or two weeks. ABS has significantly higher adsorption rates for mercury than PVC and Teflon, indicating its inappropriateness as the material for building the sampler. Teflon and PVC will be the materials of choice for the sampler. The experimental results can also be used in establishing appropriate sampling conditions in the field.

Levels of Art2+ cells but not soluble Art2 protein correlate with expression of autoimmune diabetes in the BB rat.

ART2a and ART2b are isoenzymes expressed on the surface of mature T cells and intraepithelial lymphocytes (IELs) in the rat. They exhibit both adenosine diphosphoribosyltransferase and nicotine adenine dinucleotide (NAD) glycohydrolase activities, and both can generate a transmembrane signal that modulates T cell activation. The presence or absence of ART2+ T cells modulates the expression of autoimmune diabetes in the BB rat. ART2 also circulates in a soluble form whose function is unknown. We tested the hypothesis that circulating ART2 protein regulates the expression of autoimmunity. We compared the kinetics, regulation, and source of soluble ART2 in normal rats and in rats with autoimmune diabetes. Basal levels of soluble ART2 varied greatly among strains of rats and were lowest in the diabetes-prone BB (BBDP/Wor) rat. In diabetes-resistant BB (BBDR/Wor) rats, administration of anti-ART2a antibody, which is known to induce diabetes, resulted in transient clearing of soluble ART2a that was followed rapidly by a rebound increase. Repeated treatment of BBDR/Wor rats with anti-ART2a antibody resulted in sustained supraphysiologic levels of soluble ART2a. Although the number of peripheral ART2a+ T cells is known to correlate with the expression of diabetes in BBDR/Wor rats, the level of soluble ART2a protein did not. The source of the soluble ART2 protein in the rat appeared to be the gut. The results suggest that ART2+ T cells and soluble ART2 protein may subserve different immunomodulatory functions.

Three double-blind, randomized trials evaluating the safety and tolerance of different formulations of the saponin adjuvant QS-21.

The effects of the adjuvant QS-21 in various formulations on immediate pain on injection after intramuscular injection were evaluated in three Phase I clinical trials in healthy adults. Each trial was designed as a double-blind, randomized, four-way or five-way cross-over study with each subject acting as his/her own control. In the first trial, four formulations designed to evaluate the effect of QS-21 or pH (over a range of 6--7.2) were evaluated: phosphate-buffered saline at pH 6.0 or 7.2, and 50 microg of QS-21 in phosphate-buffered saline at pH 6.0 or 7.2. Thirty-three volunteers received each of the four intramuscular injections in random order separated by approximately 1 week. The volunteers assessed the immediate injection pain from 0 to 10 (none to most pain). The data indicate that the presence of QS-21, but not pH, is associated with transient injection site pain. The second trial, which utilized the same design as the first trial, evaluated formulations of QS-21 in various excipients. Fifteen volunteers received phosphate-buffered saline, QS-21/PBS, QS-21/aluminum hydroxide, and QS-21/4 mg/ml of polysorbate 80. Polysorbate 80, but not aluminum hydroxide, reduced the mean pain score compared to QS-21/PBS. The third trial evaluated formulations of QS-21 in additional excipients. Fifteen volunteers received aluminum hydroxide (without QS-21), QS-21/PBS, QS-21/0.72% benzyl alcohol, QS-21/30 mg/ml of hydroxypropyl-beta-cyclodextrin, and QS-21/8-mg/ml of polysorbate 80. Benzyl alcohol, cyclodextrin, and the higher concentration of polysorbate 80 reduced the pain scores associated with QS-21. Hence, QS-21 is associated with injection pain in simple buffer formulations, but it is possible to improve the acceptability of QS-21-containing formulations through reformulation with certain excipients.

Atmospheric movements of lindane (gamma-hexachlorocyclohexane) from canola fields planted with treated seed.

Lindane (gamma-hexachlorocyclohexane [gamma-HCH]) is used as an insecticide in many countries. Concentrations of gamma-HCH have been found in air, water, soil, snow, and tissue samples throughout the world and concerns have been raised for its potential effects on human and ecosystem health. In Canada, gamma-HCH is primarily used as a treatment on canola (Brassica napus L) seed with an estimated 455.3 Mg applied in 1997 and 510.4 Mg in 1998. The purpose of this study was to measure gamma-HCH volatilization from fields planted with treated canola seed. Atmospheric dry and wet deposition and soil samples were collected for two growing seasons (1997 and 1998) from a canola field planted with treated seed. Atmospheric concentrations as high as 16.1 and 7.4 ng m(-3) were measured at 1 m above the canola field compared with maximum concentrations of 2.9 and 2.7 ng m(-3) measured above a grass field located 2 km away (1997 and 1998, respectively). On the basis of measurements made in this study it was estimated that between 12 and 30% of the gamma-HCH applied as canola seed treatment may volatilize and be released to the atmosphere. This would create an atmospheric loading of 66.4 to 188.8 Mg for the 6-wk period following planting, estimated from the quantity of seed sown on the Canadian prairies in 1998. Dry deposition rates and rain concentrations as high as 2,203 ng m(-2) d(-1) and 170 ng L(-1) were measured adjacent to the canola field.

Factors associated with assault-related firearm injuries in male adolescents.

PURPOSE: To identify factors associated with an increased prevalence of assault-related firearm injuries in male adolescents. METHODS: This study is a retrospective comparison of two samples of adolescent males from the same geographic localities regarding their involvement in the juvenile justice system (court involvement) and injury status (current or prior firearm injury at the time of the study). The subjects included adolescent male patients admitted to an urban, Level I trauma center for assault-related firearm injuries (court-involved and noncourt- involved, n = 65); and incarcerated juvenile offenders (prior firearm injury and no known firearm injury, n = 267). RESULTS: Two-thirds of the male assault-related pediatric firearm injury victims treated over a two-year period were involved in the juvenile justice system (court involved). Court-involved adolescents were almost 22 times more likely to have sustained an assault-related firearm injury, when compared to noncourt-involved patients with firearm injuries. Additional analysis documented recent substance use and/or involvement in criminal offenses in 82% of the victims. For most of the juvenile offenders (88%), court involvement preceded their injuries. Analysis of the injury patterns revealed an increased prevalence of truncal injuries (injuries to thorax or abdomen) in the court-involved victims, when compared to their noncourt-involved peers (40% and 14% for the court-involved and noncourt-involved samples, respectively; p <.05). Incarceration was associated with a 17-fold increase in the firearm injury prevalence over the court-involved, but not incarcerated, sample. CONCLUSIONS: These results suggest that involvement in substance use and/or the criminal justice system is associated with an increased risk of firearm injuries in male adolescents, and that an increased level of involvement in the juvenile justice system is associated with a concomitant increase in firearm injuries.

Duplicate sampling reproducibility of atmospheric residues of herbicides for paired pan and high-volume air samplers.

The reproducibility of collection of atmospheric residues of the herbicides 2,4-D and triallate as bulk (wet plus dry) deposition samples by paired pan samplers and as particulate (filter) and vapour (PUF/XAD-2 resin cartridge) samples by paired high-volume air samplers was determined. Variability of herbicide concentrations in paired bulk deposition samples was within 25% for 65 and 80% of the samples for 2,4-D and triallate, respectively, with approximately 90% of the paired samples being within a factor of 2 for both herbicides. The vapour samples of 2,4-D and triallate showed similar reproducibilities. The highest reproducibility was observed for the filter samples with 92% of the paired data sets for 2,4-D being within 25% variability. No triallate was detected in the filter samples.

Specificity of starch synthase isoforms from potato.

In higher plants several isoforms of starch synthase contribute to the extension of glucan chains in the synthesis of starch. Different isoforms are responsible for the synthesis of essentially linear amylose chains and branched, amylopectin chains. The activity of granule-bound starch synthase I from potato has been compared with that of starch synthase II from potato following expression of both isoforms in Escherichia coli. Significant differences in their activities are apparent which may be important in determining their specificities in vivo. These differences include affinities for ADPglucose and glucan substrates, activation by amylopectin, response to citrate, thermosensitivity and the processivity of glucan chain extension. To define regions of the isoforms determining these characteristic traits, chimeric proteins have been produced by expression in E. coli. These experiments reveal that the C-terminal region of granule-bound starch synthase I confers most of the specific properties of this isoform, except its processive elongation of glucan chains. This region of granule-bound starch synthase I is distinct from the C-terminal region of other starch synthases. The specific properties it confers may be important in defining the specificity of granule-bound starch synthase I in producing amylose in vivo.