Prevalence,molecular characterization,and antimicrobial resistance profiles of Listeria monocytogenes,Salmonella enterica,and Escherichia coli O157:H7 on dairy cattle farms in Jordan

This study determined the prevalence, pulsed-field gel electrophoresis profiles, and antimicrobial resistance profile of Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7 isolates from dairy cattle farms in Jordan. Samples from bulk tank milk (n = 305), cattle feces (n = 610), and rectoanal mucosal swabs (n = 610) were collected from 61 dairy cattle farms. We confirmed 32 L. monocytogenes, 28 S. enterica, and 24 E. coli O157:H7 isolates from the samples. The farm-level prevalence (at least 1 positive sample per farm) of L. monocytogenes, S. enterica, and E. coli O157:H7 was 27.9, 19.7, and 23.0%, respectively. The prevalence of L. monocytogenes, S. enterica, and E. coli O157:H7 in bulk tank milk was 7.5, 1.6, and 3.3%, respectively. The prevalence of L. monocytogenes and S. enterica in fecal samples was 1.5 and 3.8%, respectively, and the prevalence of E. coli O157:H7 in rectoanal mucosal swabs was 2.3%. Based on disk diffusion testing, all L. monocytogenes, S. enterica, and E. coli O157:H7 isolates exhibited resistance to at least 1 antimicrobial class. Multidrug resistance (resistance to 3 or more classes of antimicrobials) was exhibited by 96.9% of L. monocytogenes, 91.7% of E. coli O157:H7, and 82.1% of S. enterica isolates. Moreover, 93.8, 79.2, and 57.1% of the L. monocytogenes, E. coli O157:H7, and S. enterica isolates, respectively, were resistant to 5 or more antimicrobial classes. More than 50% of L. monocytogenes isolates were resistant to ampicillin, clindamycin, penicillin, erythromycin, quinupristin–dalfopristin, streptomycin, teicoplanin, linezolid, vancomycin, kanamycin, and tetracycline. More than 50% of S. enterica and E. coli O157:H7 isolates were resistant to ampicillin, cephalothin, nalidixic acid, kanamycin, streptomycin, amoxicillin–clavulanic acid, and tetracycline. The prevalence of the studied pathogens this study was comparable to reports from other countries. The isolated pathogens exhibited a high degree of antimicrobial resistance, suggesting that the bacterial flora of dairy cattle in Jordan are under intense antimicrobial selection pressure. Additional research is required to determine the causes and drivers of resistance, and to develop approaches to mitigating antimicrobial resistance.     

Recent advances refining galactooligosaccharide production from lactose

The production of prebiotic galactooligosaccharides (GOS) by the β-galactosidase catalysed conversion of lactose has become commercially important. Yet it remains a challenge to sufficiently understand the structure and activity of β-galactosidase, to increase the efficiency of transgalactosylation and GOS production and to improve the quality of GOS products in a rational way. This review covers the broad but related aspects of GOS synthesis including: the structure and reaction mechanism of β-galactosidase, factors effecting yield and productivity of GOS synthesis systems, the structure of GOS products, models for the kinetics of GOS synthesis and reactor configurations for GOS synthesis. It aims to couple recent discoveries with established knowledge to enhance understanding of the complex biochemistry of GOS synthesis.     

Calculator tool for determining greenhouse gas emissions for biosolids processing and end use

A greenhouse gas (GHG) calculator tool (Biosolids Emissions Assessment Model, BEAM) was developed for the Canadian Council of Ministers of the Environment to allow municipalities to estimate GHG emissions from biosolids management. The tool was developed using data from peer reviewed literature and municipalities. GHG emissions from biosolids processing through final end use/disposal were modeled. Emissions from nine existing programs in Canada were estimated using the model. The program that involved dewatering followed by combustion resulted in the highest GHG emissions (Mg CO(2)e 100 Mg(-1) biosolids (dry wt.). The programs that had digestion followed by land application resulted in the lowest emissions (-26 and -23 Mg CO(2)e 100 Mg(-1) biosolids (dry wt.). Transportation had relatively minor effects on overall emissions. The greatest areas of uncertainty in the model include N(2)O emissions from land application and biosolids processing. The model suggests that targeted use of biosolids and optimizing processes to avoid CH(4) and N(2)O emissions can result in significant GHG savings.     

Net energy for lactation of calcium salts of long-chain fatty acids for cows fed silage-based diets.

The NEL of calcium salts of long-chain fatty acids from palm oil was determined in mature Holstein cows. Twelve lactating (fed for ad libitum intake) and six nonlactating (restricted to near maintenance intake) Holstein cows were fed 0 or 2.95% fat supplement in diets formulated to contain 16 or 20% CP in a 2 x 2 factorial arrangement of treatments in a single reversal design within protein level. The fat supplement was substituted for ground corn and minerals. Two 6-d total collection balance trials were conducted during which cows were in open circuit respiration chambers. Intake of OM was lower for lactating cows fed the fat supplement (18.1 vs. 19.1 kg/d), but energy intake did not differ (93.2 Mcal/d). Total long-chain fatty acid intake was increased from 477 to 820 g/d with fat feeding. Apparent digestibility of long-chain fatty acids was increased 11.1 percentage units with increased dietary CP for lactating cows with no difference in fatty acid digestibility for the dry cows. Milk yield was higher (34.3 vs. 32.0 kg/d) with fat feeding, but milk energy yield did not differ (22.6 Mcal/d). The NEL of the fat supplement was estimated from the incremental differences in energy values within cows, assuming NEL of corn replaced by fat to be 1.96 Mcal/kg DM, and was determined to be 6.52 Mcal/kg DM (SE = 1.74). The efficiency of the use of metabolizable energy for lactation from dietary fat was 77.2%. The energy in calcium salts of long-chain fatty acids is utilized efficiently for lactation in mature cows.     

Real-time craving and mood assessments before and after smoking.

This study explored some quandaries concerning craving and mood as motivators to smoke. Craving and negative mood have long been associated with day-to-day smoking as two of the primary motivational forces behind the maintenance of the behavior, as well as significant barriers in smokers' attempts to quit. Craving remains a clinically relevant phenomenon, with most smokers describing craving as a troublesome problem when quitting. Smokers' self-reports of negative mood, as an antecedent for smoking, are so robustly reported that many models of nicotine dependence have incorporated a critical role for negative mood in maintaining smoking behavior. However, several naturalistic studies that collected mood ratings with hand held computers from smokers in real time, just before smoking a cigarette, have provided scant evidence that negative mood plays a major role in motivation to smoke. No study to date has examined craving and mood data as a consequence of smoking, that is, collecting the same data immediately after smoking. This study used personal digital assistants (PDAs) to collect craving and mood data immediately before smoking, immediately after smoking, and at random times of day. Nontreatment seeking smokers (N = 72) carried a PDA for an average of 10 days while they recorded their smoking behavior. Results showed that craving and negative mood ratings were lowest immediately after smoking compared with immediately before smoking and at random times of day. These findings suggest that smokers may be at least partially motivated to smoke to lower their craving and improve their mood states.     

Perfluorinated compounds in house dust from Ohio and North Carolina, USA

The perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have come under increasing scrutiny due to their persistence, global distribution, and toxicity. Given that their human exposure routes remain poorly characterized, the potential role of house dust needs to be more completely evaluated. In this study, new methods for the analysis of 10 PFAAs and three fluorinated telomer alcohols (FTOHs) were developed for dust samples collected from homes (n = 102) and day care centers (n = 10) in Ohio and North Carolina in 2000-2001. FTOHs were measured by GC/ MS and PFAAs were analyzed by LC-MS/MS. PFOS and PFOA were the most prominent compounds detected, occurring in over 95% of the samples at median concentrations of 201 and 142 ng/g of dust, respectively. Maximal concentrations of PFOS were 12 100 ng/g (95th percentile, 2240 ng/g), PFOA 1960 ng/g (95th percentile, 1200 ng/g), and perfluorohexanesulfonate (PFHS) 35 700 ng/g (95th percentile, 2300 ng/g). The 8:2 FTOH, which is volatile and can degrade to PFOA, had a maximum concentration of 1660 ng/g dust (95th percentile, 669 ng/g). These results indicate that perfluorinated compounds are present in house dust at levels that may represent an important pathway for human exposure.     

Atmospheric emission of reactive nitrogen during biofuel ethanol production

This paper evaluates emissions to the atmosphere of biologically available nitrogen compounds in a region characterized by intensive sugar cane biofuel ethanol production. Large emissions of NH3 and NOx, as well as particulate nitrate and ammonium, occur at the harvest when the crop is burned, with the amount of nitrogen released equivalent to approximately 35% of annual fertilizer-N application. Nitrogen oxides concentrations show a positive association with fire frequency, indicating that biomass burning is a major emission source, with mean concentrations of NOx doubling in the dry season relative to the wetseason. During the dry season biomass burning is a source of NH3, with other sources (wastes, soil, biogenic) predominant during the wet season. Estimated NO2-N, NH3-N, NO3- -N and NH4+ -N emission fluxes from sugar cane burning in a planted area of ca. 2.2 x 10(6) ha are 11.0, 1.1, 0.2, and 1.2 Gg N yr(-1), respectively.     

Mercury bioaccumulation in forage fish communities invaded by rainbow smelt (Osmerus mordax)

We compared total mercury concentrations ([Hg]) among 6 forage fish species in 25 central Canadian lakes and related [Hg] to adjusted-delta15N (an index of trophic position), delta13C, growth rate, and a suite of environmental variables. Growth rates were also compared among species and related to environmental variables. We found that rainbow smelt (Osmerus mordax), a recent invader in many of these lakes, had intermediate [Hg] and growth rates relative to other species. Forage fish growth rates differed significantly among species and were related to latitude (inverse relationship) and lake conductivity (positive relationship). Mercury concentrations also differed significantly among species and the strongest predictors were growth rate and lake conductivity; [Hg] was significantly and negatively related to both. Adjusted-delta15N explained very little variation in [Hg] and was significant only when the analysis was restricted to biotic variables. These results indicate that biomagnification may not be observed at fine scales of trophic differentiation and that rainbow smelt are unlikely to cause post-invasion [Hg] increases in most predatory fish species.     

Formulation and properties of model beverage emulsions stabilized by sucrose monopalmitate: Influence of pH and lyso-lecithin addition

There is a growing trend toward utilizing more label friendly ingredients in foods and beverages. In this study, we focused on the utilization of sucrose monopalmitate (SMP) as a non-ionic surfactant for stabilizing acidic beverages. Orange oil-in-water emulsions (5% (w/w) oil) stabilized by SMP were prepared using high pressure homogenization (pH 7). The minimum droplet diameter was around 130 nm, while the minimum mass ratio of SMP-to-oil required to produce small droplets was 0.1-to-1. Extensive droplet aggregation occurred when the pH of the emulsions was reduced from pH 7 to 3, with the mean particle diameter increasing from around 0.13 to 7.25 μm. This effect was attributed to an appreciable reduction in droplet charge when the pH was reduced (ζ ≈− 35 mV at pH 3 and − 2 mV at pH 3) thereby decreasing the electrostatic repulsion between droplets. It was proposed that the negative charge on the SMP-coated droplets was due to the presence of anionic substances within the droplets, such as palmitic acid (pK_a ≈ 4.9). Palmitic acid may have been an impurity in the original ingredient or it may have been generated due to degradation of SMP during storage. The addition of anionic lyso-lecithin markedly improved the stability of the emulsions to droplet aggregation and phase separation at low pH, which was attributed to an increased electrostatic repulsion between the droplets. This study has important consequences for the formulation of acidic beverage emulsions with improved stability and physicochemical performance.     

Metabolomics reveals target and off-target toxicities of a model organophosphate pesticide to roach (Rutilus rutilus): implications for biomonitoring

The ability of targeted and nontargeted metabolomics to discover chronic ecotoxicological effects is largely unexplored. Fenitrothion, an organophosphate pesticide, is categorized as a "red list" pollutant, being particularly hazardous to aquatic life. It acts primarily as a cholinesterase inhibitor, but evidence suggests it can also act as an androgen receptor antagonist. Whole-organism fenitrothion-induced toxicity is well-established, but information regarding target and off-target molecular toxicities is limited. Here we study the molecular responses of male roach ( Rutilus rutilus ) exposed to fenitrothion, including environmentally realistic concentrations, for 28 days. Acetylcholine was assessed in brain; steroid metabolism was measured in testes and plasma; and NMR and mass spectrometry-based metabolomics were conducted on testes and liver to discover off-target toxicity. O-demethylation was confirmed as a major route of pesticide degradation. Fenitrothion significantly depleted acetylcholine, confirming its primary mode of action, and 11-ketotestosterone in plasma and cortisone in testes, showing disruption of steroid metabolism. Metabolomics revealed significant perturbations to the hepatic phosphagen system and previously undocumented effects on phenylalanine metabolism in liver and testes. On the basis of several unexpected molecular responses that were opposite to the anticipated acute toxicity, we propose that chronic pesticide exposure induces an adapting phenotype in roach, which may have considerable implications for interpreting molecular biomarker responses in field-sampled fish.