Exposure and Multiple Lines of Evidence Assessment of Risk for PCBs Found in the Diets of Passerine Birds at the Kalamazoo River Superfund Site,Michigan

Dietary exposures of passerine birds at the Kalamazoo River, Michigan, were examined due to the presence of polychlorinated biphenyls (PCBs) in the terrestrial and aquatic food webs. Average potential daily doses in diets were 6- to 29-fold and 16- to 35-fold greater at a contaminated location than at a reference location for PCB exposures quantified as total PCBs and 2,3,7,8–tetrachlorodibenzo-p-dioxin equivalents (TEQs), respectively. Birds with diets comprised of primarily aquatic insects had greater dietary exposure than birds with diets of primarily terrestrial insects. Risk associated with dietary exposure varied with the selection of the threshold for effects including hazard quotients, which exceeded 1 in instances where the most conservative toxicity reference values were utilized. Risk based on concentrations of PCBs in the tissues indicated little risk to avian species, and co-located studies evaluating reproductive health did not suggest that observed incidences of diminished reproductive success were related to PCB exposure. Measures of risk based on comparison to toxicity reference values (TRVs) were consistent with direct measures of ecologically relevant endpoints of reproductive fitness, but uncertainty exists in the selection of threshold values for effects in these species especially based on TEQs. This is largely due to the absence of species-specific, dose-response relationships. Therefore, the best estimate of risk is through the application of multiple lines of evidence.     

Polychlorinated Biphenyls in the Plasma and Preen Oil of Black-Footed Albatross (Diomedea nigripes) Chicks and Adults on Midway Atoll,North Pacific Ocean

Polychlorinated biphenyls (PCBs) are ubiquitous in the environment. Midway Atoll, located in the North Pacific Ocean, was occupied by the military during and after World War II. However, Midway Atoll has become a national wildlife refuge and home to many different seabirds today, including the black-footed albatross (Diomedea nigripes) (BFAL). The profiles and toxic equivalents (TEQ) of PCB congeners in the plasma and preen oil of BFAL chicks and adults were determined in this study. The concentrations of the total PCBs in the plasma samples of chicks and adults collected in Midway Atoll ranged from 2.3 to 223.8 (mean 80.1) and 22.8 to 504.5 (mean 158.6) ng g^-1 (wet weight, ww), respectively. The TEQs ranged from 0.2 to 0.6 (mean 0.4) and 0.4 to 1.6 (mean 0.9) pg g^-1 ww, respectively, in the plasma samples of chicks and adults from Midway Atoll. The major congeners in the plasma samples of chicks and adults included PCBs 31, 87, 97, 99, 118, 138, 153, and 180, accounting for 70% of the total PCBs. The concentrations of the total PCBs in the adult preen oil samples ranged from 1693 to 39404 (mean 10122) ng g^-1 (ww), of which 97% were PCBs 105, 118, 128, 138, 153, 161, 172, and 183.     

Induction of non-protein thiols and phytochelatins by cadmium in Eichhornia crassipes

Abstract

Impact of root Cd concentration on production of cysteine, non-protein thiols (NP-SH), glutathione (GSH), reduced glutathione (GSSG), and phytochelatins (PCs) in Eichhornia crassipes exposed to different dilutions of brass and electroplating industry effluent (25%, 50%, and 75%), and synthetic metal solutions of Cd alone (1, 2.5, and 3.5?ppm) and with Cr (1?ppm Cd + 1?ppm Cr, 2.5?ppm Cd + 3?ppm Cr, and 3.5?ppm Cd + 4?ppm Cr) was assessed in a 45?days study. Different treatments were used to understand and compare differential antioxidant defense response of plant under practical drainage (effluent) and experimental synthetic solutions. The production of NP-SH and cysteine was maximum under 2.5?ppm Cd + 3?ppm Cr treatments i.e., 1.78?µmol/g fw and 288?nmol/g fw, respectively. The content of GSH declined whereas that of GSSG increased progressively with exposure duration in all treatments. HPLC chromatograms revealed that the concentrations of PC2, PC3, and PC4 (248, 250, and 288?nmol-SH equiv.g^?1 fw, respectively) were maximum under 1?ppm Cd, 1?ppm Cd + 1?ppm Cr, and 2.5?ppm Cd + 3?ppm Cr treatments, respectively. PC2, PC3, and PC4 concentrations increased with Cd accumulation in the range 812–1354?µg/g dry wt, 1354–2032?µg/g dry wt and 2032–3200?µg/g dry wt, respectively. Thus, the study establishes a direct proportionality relationship between concentration/length of phytochelatins and root Cd concentrations, upto threshold limits, in E. crassipes.     

Evaluation of adrenocortical function in Florida manatees (Trichechus manatus latirostris)

The study objectives were to determine the predominant manatee glucocorticoid; validate assays to measure this glucocorticoid and adrenocorticotropic hormone (ACTH); determine diagnostic thresholds to distinguish physiological vs. pathological concentrations; identify differences associated with sex, age class, female reproductive status, capture time, and lactate; and determine the best methods for manatee biologists and clinicians to diagnose stress. Cortisol is the predominant manatee glucocorticoid. IMMULITE 1000 assays for cortisol and ACTH were validated. Precision yielded intra‐ and inter‐assay coefficients of variation for serum cortisol: ≤23.5 and ≤16.7%; and ACTH: ≤6.9 and ≤8.5%. Accuracy resulted in a mean adjusted R²≥0.87 for serum cortisol and ≥0.96 for ACTH. Assay analytical sensitivities for cortisol (0.1 µg/dl) and ACTH (10.0 pg/ml) were verified. Methods were highly correlated with another IMMULITE 1000 for serum cortisol (r=0.97) and ACTH (r=0.98). There was no significant variation in cortisol or ACTH with sex or age class and no correlation with female progesterone concentrations. Cortisol concentrations were highest in unhealthy manatees, chronically stressed by disease or injury. ACTH was greatest in healthy free‐ranging or short‐term rehabilitating individuals, peracutely stressed by capture and handling. Cortisol concentrations ≥1.0 µg/dl were diagnostic of chronic stress; ACTH concentrations ≥87.5 pg/ml were diagnostic of peracute stress. In healthy long‐term captive manatees, cortisol (0.4±0.2 µg/dl) and ACTH (47.7±15.9 pg/ml) concentrations were lower than healthy free‐ranging, short‐term rehabilitated or unhealthy manatees. Capture time was not significantly correlated with cortisol; ACTH correlation was borderline significant. Cortisol and ACTH were positively correlated with lactate. Zoo Biol 30:17–31, 2011. © 2010 Wiley‐Liss, Inc.     

Performance of AERMOD and CALPUFF models on SO2 and NO2 emissions for future health risk assessment in Tema Metropolis

AERMOD results were compared with the reported CALPUFF results to estimate the concentrations and temporal distributions of SO₂ and NO₂ from Tema Oil Refinery with particlar attention to heavy rainy season (HRS), minor rainy season (MRS), and dry season (DS). Statistical indices, including the fractional bias (FB), geometric mean variance (VG), normalized mean square error (NMSE), index of agreement (IOA), and geometric mean bias (MG), were used to assess the reliability of the models. Overall, AERMOD better predicted ambient SO₂ and NO₂ levels than the reported CALPUFF model. For SO₂, AERMOD showed a good agreement with FB, IOA, and MG while CALPUFF showed a good prediction in NMSE and VG. Also, AERMOD predicted NO₂ well with NMSE, IOA, MG, and VG compared with FB for CALPUFF. The MRS results showed higher hourly maximum concentrations (107.4 µg/m³ for SO₂ and 31.7 µg/m³ for NO₂). Maximum daily concentrations were slightly higher in HRS (37.7 µg/m³ for SO₂ and 9.6 µg/m³ for NO₂) compared to MRS and DS. The performace of the models may provide a better understanding for future epidemiological studies.     

Distribution and ecological risks of polychlorinated biphenyls (PCBs) in surface sediment of the Forcados River,Niger Delta,Nigeria

Concentrations of Σ15 PCBs in sediments of the Forcados River, Nigeria, were determined in 2012 to provide information on the profile, sources and ecotoxicological risks of PCBs in the sediment. The screening concentrations of PCBs were quantified using a gas chromatograph equipped with a Ni-63 electron capture detector. The concentrations of the Σ15 PCBs ranged from 2.7 to 202.3 µg kg???1 with a mean concentration of 46.5 µg kg???1. The composition of PCB congeners was clearly dominated by octa-PCBs, hepta-PCBs and hexa-PCBs, constituting 68.1% to 93.7%, respectively, of the total amounts of PCBs. All sites had Σ15 PCB levels below the prescribed probable effect concentrations, and therefore no adverse effects are expected for the majority of sediment-dwelling organisms of the Forcados River system.     

Human Melatonin and Cortisol Circadian Rhythms in Patients with Coronary Heart Disease

Cortisol and melatonin have well known circadian rhythms, coupled to the solar day. Melatonin has been shown to serve as an endogenuous “Zeitgeber” (time giver) and is secreted by the human pineal gland throughout the night but not during the day. Patients with coronary heart disease (CHD) have significant depressed nocturnal melatonin secretion compared to healthy individuals (Brugger et al., 1995). In addition to our previous study we measured serum concentrations of cortisol to evaluate whether the circadian rhythm of cortisol secretion is also different in patients with CHD. Blood was collected by venous puncture at 0200 and at 1400, serum separated and kept frozen at -20°C until analysis. Cortisol and melatonin were measured with a commercially available radioimmunoassay according to the instructions of the manufacturer. Nineteen patients with angiographically documented CHD (mean age 53 years) participated in this study. As control group served 12 adults without any signs of CHD. Melatonin serum concentrations (median; mean ± SD) at night were significantly depressed in patients with coronary heart disease (7.8; 8.6 ± 3.3 pg/ml) in comparison to the control group (38.0; 45.4 ± 24.1 pg/ml) p < 0.01. Melatonin in the afternoon was not detectable in either of the groups. Cortisol values at night were significantly raised in patients with coronary heart disease (6.0; 7.2 ± 3.7 µg/dl) in comparison to the control group (2.7; 3.8 ± 2.9 µg/dl) p < 0.05. Cortisol levels in the afternoon were also elevated in patients with CHD (8.9; 9.5 ± 3.8 µg/dl) but there was no significant difference compared to controls (6.8; 6.9 ± 4.5 µg/dl). The results of the present study indicate that patients with coronary heart disease have atypical secretory patterns of nocturnal cortisol and melatonin secretion.     

Monitoring of level of mean concentration and toxicity equivalence (TEQ) of polychlorinated biphenyls (PCBs) in selected vegetables,beans and grains in khanewal and multan,Pakistan

Contamination of food chain by Polychlorinated biphenyls through use of pesticides, electric and industrial waste poses human health risk. In previous studies, PCB species were stated as endocrine disrupting pollutants and showed toxic health effects like cancerous and noncancerous in animals. The aim of this study was to investigate the levels of PCBs and its toxicity equivalence in food item from plant source to evaluate the health risk in Khanewal and Multan, Pakistan. Samples were collected and processed for further analysis of PCB species through GC/MS after extraction and clean up. The mean concentrations of PCBs ranged as 2.71–151.67 ng/g in beans and grains and 2.30–97.00 ng/g dry weight in vegetables and were lower than 200–3000 ng/g PCBs recommended by FDA tolerance level for all foods. The mean concentrations of two NDL-PCB species detected in all vegetables, beans and grains except S.indicum and T.aestivum were lower than maximum allowable concentration of non-dioxin like PCBs i.e. 40ngg^?1 reported by European Commission. Mean TEQ of sum of 14 PCB species ranged as 1.52–5.91 ng-WHO-TEQg^?1 in vegetables and 1.46–10.04 ng-WHO-TEQg^?1 in beans and grains. The present study concluded that the mean concentrations and mean TEQs of PCB species in most of the vegetables, beans and grains were found safe but due to higher consumption rate of some vegetables and grains, posed the moderate level of risk for human health. This study emphasizes on an implement of the strict rules regarding the use of restricted chemicals to diminish the effluence in food chains. Current research will be useful in up gradation of effective measures to reduce the poisonous contribution of PCB sources and the sustainability of terrestrial ecosystem in the country.     

Using tree leaves and barks collected from contaminated and uncontaminated areas as indicators of air metallic pollution

Abstract

The aim of this study was to show the usefulness of woody species in assessing air pollution by cadmium, copper, lead, and zinc. For this, washed leaves, unwashed leaves, and barks of a coniferous species (Cupressus sempervirens var. fastigiata) and a broadleaved one (Eucalyptus cladocalyx F. Muell) were analyzed for cadmium, copper, lead and zinc contents. A transect sampling approach was carried out during spring 2016. Fifty stations were selected along an intensive traffic road, and three in a control area. The results showed that the highest concentrations were recorded in barks for copper (21.86?µg/g, 23.33?µg/g) and lead (14.53?µg/g, 63.33?µg/g), and in unwashed leaves for cadmium (0.57?µg/g, 1.19?µg/g) and zinc (48.94?µg/g, 47.6?µg/g) for E. cladocalyx F. Muell, and C. sempervirens var. fastigiata, respectively. Lead and zinc are the most accumulated metals compared to cadmium and copper in all samples. The studied metal contents in urban area were significantly higher than that of the control one. This represents that traffic road has influenced the metals contamination of the surrounding area. Results of the bioconcentration factor (BCF) for both species indicate that the studied species could be used as biomonitors to identify ecological problems and to predict effect on wildlife habitats. The highest values of metal accumulation index (MAI) indicate the effectiveness of these trees for controlling the air metals in the polluted areas. Result shows too that the studied species could be used for phytoextraction of heavy metals from the polluted soils and/or air.     

Dietary Arsenic Intake in Taiwanese Districts with Elevated Arsenic in Drinking Water

Inorganic arsenic in dietary staples (i.e., yams and rice) may have substantially contributed to exposure and adverse health effects observed in an endemic Taiwanese population historically exposed to arsenic in drinking water. Observations of this population were used by the U.S. Environmental Protection Agency to derive toxicity values that form the basis for arsenic risk assessment and various regulations in the United States. However, data were previously insufficient to accurately estimate dietary intake. Rice and yam samples collected in 1993 and 1995 from Taiwanese districts with endemic arsenic were analyzed for total arsenic and for inorganic and organic mono and dimethylarsenic. The acid digestion techniques used in the analyses are among the best to preserve organic arsenic in the test sample. Furthermore, concurrent analyses of the proportion of inorganic arsenic in split samples of rice and yams collected in the 1995 investigation were in good agreement, despite using a different digestion method. These data support a likely mean dietary intake of 50?µg/day with a range of 15 to 211?µg/day. Consideration of dietary intake may result in a downward revision of the assumed potency of ingested arsenic as reflected in EPA's toxicity values.     

Detection of water toxicity using cytochrome P450 transgenic zebrafish as live biosensor: for polychlorinated biphenyls toxicity

Cytochrome P450 (CYPs) is significant in degradation of endogenous substrates and detoxification of carcinogens, therefore it is a biomarker for assessment of polycyclic aromatic hydrocarbons (PAHs) level in aquatic environment. In the present study, a transgenic line of zebrafish had been generated using a CYP-green fluorescence protein (CYP-GFP) construct, driven by CYP1A1 promoter. Polychlorinated biphenyls (PCBs) were used as toxicant, in concentrations of 0.02 μg/ml, 0.04 μg/ml, 0.08 μg/ml, 0.4 μg/ml, and 0.8 μg/ml. The transgenic control fish showed low intensity of fluorescence in the liver. After exposed to PCBs, zebrafish had morphological changes such as expansion of yolk, contortion of tails and inflation of pericardial area. Green fluorescence signals were found to express according to concentrations and time. The green fluorescence signal was most intense after treatment with 0.08 μg/ml PCBs. However, the maximum area of green fluorescent signal was found at 0.04 μg/ml PCBs. GFP started to express at 3h exposure to PCBs, increasing its intensity until 6 h exposure, and then level off. Since the GFP expression is fast responding and is sensitive to low PAHs concentrations, transgenic fish is a good tool for live imaging and monitoring of aquatic contamination.     

Adult:Child Differences in the Intraspecies Uncertainty Factor: A Case Study Using Lead

Adults and children differ in their susceptibility to the toxic effects of lead. Lead was therefore used as a case study to evaluate intraspecies differences by comparing the adult and child minimal Lowest Observed Adverse Effect Level (LOAEL) or the No Observed Adverse Effect Level (NOAEL), allowing an evaluation of the ten-fold intraspecies uncertainty factor (UF). The lead intakes (in µg/kg/d) necessary to achieve target blood lead (PbB) levels reflecting the minimal LOAEL or NOAEL were determined using biokinetic slope factors (BKSFs), which relate lead uptake to PbB levels. The analyses assumed chronic, low-level oral exposure to lead, and the response of a typical adult and child. Child analyses used a target geometric mean (GM) PbB of 4.6?µg/dL (95% of population <10?µg/dL), resulting in lead intakes of 1.9?µg/kg/day (assuming 100% soluble lead) and 4.9?µg/kg/day (assuming 25% soluble lead and 75 % soil lead). Adult analyses assumed intake of 100 % soluble lead, and used target GM PbB levels of 4.2?µg/dL (95% of population <11.1 µg/dL) and 11.4?µg/dL (95% of population <30?µg/dL), resulting in lead intakes of 1.9?µg/kg/day and 5.1?µg/kg/day, respectively. The results indicate that despite the greater vulnerability of young children to the effects of lead as compared to adults, the minimal LOAEL or NOAEL for lead is remarkably similar between children and adults. In this case, the application of a tenfold intraspecies uncertainty factor to adjust the adult minimal LOAEL or NOAEL for a child would be unnecessary, despite the well-established vulnerability of children to lead.     

Assessment of persistent organochlorine compounds contamination on the Lake Victoria water and sediments: a case study in Tanzania

The current study was conducted to establish the levels of organochlorine pesticides (OCPs), its degradation products, and indicatory polychlorinated biphenyls (PCBs) in water and sediments from Lake Victoria in Tanzania. Seven indicator PCBs were identified in sediments, and five were identified in water. The PCBs loading ranged from lower than the limit of detection (LOD) to 10.28 µg kg^?1 DW and 0.95 to 2.24 µg l^?1 in sediments and water, respectively. PCBs, CB 138 and CB 153 dominated the load, because of their chemical stability and high degree of chlorination. In addition, ten OCPs were identified in sediments, and seven OCPs were identified in water. The levels of organochlorine compounds in sediments were higher than in water samples, implying that sediments may serve as a sink for these compounds. The presence of these compounds is probably as a result of either historical use, long-range environmental transport or environmental persistence. The levels of organochlorine compounds in the lake water and sediments are below the maximum residue limit set by EU and FAO, except for aldrin and dieldrin. Based on the Threshold Effect Concentration (TEC) for freshwater ecosystems, aldrin and dieldrin are the only OCPs that seem to be a threat to the lake environment.     

Longitudinal Exposure to Selected Pesticides in Drinking Water

The presence and temporal fluctuations of concentrations of insecticides and herbicides in natural waters has been well documented. Little, however, is known about exposure to pesticides through drinking water for the general population. Concentrations often pesticides, including 4,4′DDE and atrazine, were measured up to six times at equally spaced intervals over a 1-year period in drinking water of 80 randomly selected residences in Maryland. Atrazine was detected in 228 (57.9%) of the drinking water samples with a mean of 0.15?µg/L, with standard deviation 0.12?µg/L, median 0.17?µg/L, and range <0.037 to 0.46?µg/L. 4,4′DDE was found in 22 (5.6%) water samples; no other target analytes were detected. Concentrations of atrazine in drinking water were found to vary over a 12-month period with the greatest concentrations in the late summer and fall and the lowest in the early spring. Atrazine concentrations in drinking water were influenced more by differences in levels among residences than by time of year. Seven-day average exposures and exposures per unit body weight to atrazine in drinking water exhibited a similar temporal pattern. Among individuals, drinking water consumption rate was a more important determinant of atrazine exposure (µg/d) and exposure per unit body weight (µg/kg/d) than atrazine concentration in drinking water or body weight.     

Seasonal-spatial distributions,congener profile,and risk assessment of polychlorinated biphenyls (PCBS) in the surficial sediments from the coastal area of Bangladesh

A comprehensive congener specific assessment of polychlorinated biphenyls (PCBs) was conducted for the first time in Bangladesh. All 209 PCB congeners in the surficial coastal sediments from the coastal areas of Bangladesh were analyzed by GC-MS/MS. The total concentrations of PCBs (∑PCBs) varied from 5.27 to 92.21 and 4.61 to 105.3 ng/g dw in winter and summer, respectively, and the ranges were comparable to or higher than those recorded in the sediments from the coastal areas of India, Korea, China, and Taiwan. The seasonal difference in the levels of PCBs was not statistically significant (p > 0.05). The spatial distribution revealed that the areas with recent urbanization and industrialization (Chittagong, Cox’s Bazar and Sundarbans) were more contaminated with PCBs than the unindustrialized area (Meghna Estuary). Moderately chlorinated (4–6 Cl) homologs dominated PCB profiles. A set of congeners based on their detection frequencies and abundance were identified and categorized as potential environmental marker PCBs, which can be used for the future selective monitoring studies where there would be limitations on whole congener assessment. Ecotoxicologically, the sedimentary PCB concentrations exceeded some of the existing environmental quality standards, suggesting a potential threat to the aquatic organisms in the Bangladeshi coastal areas.     

Selenium Was a Time Bomb

At high dietary levels, selenium causes adverse effects in animals. Aquatic birds are among the more sensitive wildlife species, because their reproduction can be impaired when dietary selenium levels exceed about 4?µg/g (dry weight basis). Fish can also be adversely affected at similar dietary exposures. Conversely, low dietary levels of selenium (below about 0.1 to 0.5?µg/g) cause nutritional deficiencies in domestic animals, fish, and wildlife. Selenium became recognized as a significant environmental contaminant for wildlife in 1983, with the discovery of developmental abnormalities and excessive embryonic mortality in aquatic birds at Kesterson Reservoir, California. There are a number of environmental settings in which selenium warrants concern and must be considered carefully in relation to potential effects to fish and wildlife, and there may still be surprises in which it unexpectedly becomes a significant ecological issue. However, if selenium is included among the chemicals of potential ecological concern when ecological risk assessments are planned and conducted, there is enough information to thoroughly evaluate its environmental significance in much the same way as other contaminants. The main difference is that it is essential to have a good understanding of selenium's occurrence, complex biogeochemistry, and ecotoxicology to avoid serious errors.     

Comprehensive in vitro regeneration study with SCoT marker assisted clonal stability assessment and flow cytometric genome size analysis of Carthamus tinctorius L.: an important medicinal plant

An efficacious and reproducible in vitro regeneration technique for safflower was established using varying concentrations and composition of plant growth regulators (PGRs) supplemented Murashige and Skoog (MS) medium. Successful in vitro seed germination in half strength MS (H-MS) with 1.4 µM GA₃ resulted in procurement of sterile explants (cotyledons, apical meristems) for in vitro study. Callogenesis (2.2 µM BAP?+?2.7 µM NAA), indirect organogenesis of shoot buds (0.54 µM NAA?+?9.08 µM TDZ), somatic embryogenesis (2.2 µM BAP?+?5.4 µM NAA) and somatic embryo germinated plantlets (H-MS?+?1.4 µM GA₃?+?2.2 µM BAP?+?5.4 µM NAA) were successfully obtained. Histological study and scanning electron micrographs of embryogenic callus revealed pre-globular, heart-shaped and torpedo stages of dicot embryogeny. H-MS?+?8 µM NAA showed maximum rhizogenic response with a mean root and shoot length of 17.5 mm and 48.50 mm respectively in 2.2 µM BAP?+?0.54 µM NAA bearing an average of 9 capitula per plantlet with 70% post transplantation survival rate. True to type nature of the regenerates was confirmed using Start Codon Targeted (SCoT) marker, exhibiting 100% and 97.3% monomorphic bands for direct and somatic embryo regenerated plants respectively. Flow cytometry method (FCM) was employed for 2C DNA content analysis. The histogram peaks of 2C nuclear DNA content of in vitro regenerated safflower (direct and embryo derived) were similar to the peak of field grown donor plant. 2C nuclear DNA content of field grown, direct and somatic embryo regenerated C. tinctorius was 2.65?±?0.04 pg, 2.62?±?0.06 pg and 2.68?±?0.04 pg respectively, further verifying genetic homogeneity. All things considered, the above protocol is insusceptible to genetic alteration and can be used for large scale production and sustainable utilization of desired genotype.

     

Calculating the Dim Light Melatonin Onset: The Impact of Threshold and Sampling Rate

The dim light melatonin onset (DLMO) is the most reliable circadian phase marker in humans, but the cost of assaying samples is relatively high. Therefore, the authors examined differences between DLMOs calculated from hourly versus half-hourly sampling and differences between DLMOs calculated with two recommended thresholds (a fixed threshold of 3 pg/mL and a variable “3k” threshold equal to the mean plus two standard deviations of the first three low daytime points). The authors calculated these DLMOs from salivary dim light melatonin profiles collected from 122 individuals (64 women) at baseline. DLMOs derived from hourly sampling occurred on average only 6–8?min earlier than the DLMOs derived from half-hourly saliva sampling, and they were highly correlated with each other (r?≥?0.89, p?<?.001). However, in up to 19% of cases the DLMO derived from hourly sampling was >30?min from the DLMO derived from half-hourly sampling. The 3 pg/mL threshold produced significantly less variable DLMOs than the 3k threshold. However, the 3k threshold was significantly lower than the 3 pg/mL threshold (p?<?.001). The DLMOs calculated with the 3k method were significantly earlier (by 22–24?min) than the DLMOs calculated with the 3 pg/mL threshold, regardless of sampling rate. These results suggest that in large research studies and clinical settings, the more affordable and practical option of hourly sampling is adequate for a reasonable estimate of circadian phase. Although the 3 pg/mL fixed threshold is less variable than the 3k threshold, it produces estimates of the DLMO that are further from the initial rise of melatonin. (Author correspondence: Helen_J_Burgess@rush.edu)     

In vitro antimicrobial activity of plant extracts against Pseudomonas syringae pv. actinidiae causal agent of bacterial canker in kiwifruit

Abstract

Pseudomonas syringae pv. actinidiae (Psa), the causal agent of bacterial canker of kiwifruit, is considered the main pathogen of yellow-, green- and red-fleshed kiwifruit. All major kiwifruit producing countries in the world have been affected by this bacterial pathogen, leading to substantial economic losses. The control of bacterial canker of kiwifruit is based only on preventive methods or on the use of copper compounds that can cause phytotoxicity problems. In this study, the in vitro antibacterial activity of seven different plant extracts against eight Psa strains has been evaluated. The inhibition of 100% of the Psa growth was observed, after 24?h, for the extracts of Polygonum cuspidatum roots (POL-roots), Hypericum perforatum roots elicited with chitosan oligosaccharides (HYP-COS roots) and non-fermented grape pomace (ITA-pomace). The strongest antibacterial activity was exhibited by POL-roots, with a geometric mean of minimum inhibitory concentration of 100% of growth (GMMIC₁₀₀) of 105.11 µg/mL after 24?h, and with a GMMIC₁₀₀ value of 148.65 µg/mL after 48?h. Moreover, POL-roots extract showed the best bactericidal activity with a GMMBC of 210.22 µg/mL. No phytotoxic activity was observed up to 15 days in the leaves of Actinidia chinensis “Belen” treated with plant extracts at 500 µg/mL.     

Estimation of Mercury Intake from Selected Fish Species Commercialized in Alexandria,Southeastern Mediterranean Sea,Egypt

Total Hg concentrations were determined in muscle tissue of some fishes with different feeding habits (12 fish species) obtained from the main fishing locations along the Alexandria coast, a region particularly impacted by historic industrial Hg activities. Health risks to human via dietary intake of the edible portion of fish were assessed by the target hazard quotients (THQs). Mercury maximum concentrations corresponding to fish muscle tissue were found in L. mormyrus, S. rivulatus, and S. luridus (3.56, 2.94, and 1.35 μg g^?1 wet weight, respectively). Thence most of these three species bass (75% of L. mormyrus, 76% of S. rivulatus, and 54% of S. luridus) were greater than a 0.47 μg g^?1 threshold corresponding to a 1 meal per month consumption limit. M. cephalus, S. aurita, S. chrysotaenia, B. boops, and A. djedaba bass (100%) were less than a 0.12 μg g^?1 threshold corresponding to a 4 meals per month safe consumption limit. Mercury THQs values, ranging from 0.11–1.76, were of concern. In particular, the health risk was mainly ascribed to consumption of S. rivulatus (1.72) and L. mormyrus (1.76), although also the TEQs values caused by consuming S. luridus (0.64) were rather high, being close to 1.