Chemical composition of arctic snow: concentration levels and regional distribution of major elements

At the end of the northern winter 1996/1997, 21 snow samples were collected from 17 arctic localities in Norway, Sweden, Finland, Svalbard, Russia, Alaska, Canada, Greenland and Iceland. Major element concentrations of the filtered (0.45 mum) melted snow indicate that most samples are consistent with a diluted seawater composition. Deviations from this behaviour indicate additional SO(4)(2-) and Cl(-) relative to seawater, suggesting a minor contribution from (probably local) coal combustion emissions (Alaska, Finland, Sweden, Svalbard). The samples with the highest Na and Cl(-) content (Canada, Russia) also have higher Na/SO(4)(2-) and Cl(-)/SO(4)(2-) ratios than seawater, suggesting a slight contamination from (probably local) deicing activities. Local soil or rock dust inputs in the snow are indicated by 'excess' Ca contents (Alaska, Svalbard, Greenland, Sweden). No overall relationship was found between pH (range: 4.6-6.1) and total or non-seasalt SO(4)(2-) (NSS), suggesting that acidification due to long-range transport of SO(2) pollution is not operating on an arctic-wide scale. In a few samples (Alaska, Finland, Sweden, Svalbard), a significant proportion (>50%) of SO(4)(2-) is non-marine in origin. Sources for this non-marine SO(4)(2-) need not all be found in long-range atmospheric transport and more likely sources are local industry (Finland, Sweden), road traffic (Alaska) or minor snow-scooting traffic (one Svalbard locality). A few samples from northern Europe show a relatively weak trend of decreasing pH with increasing NO(3)(-).     

Effects of potential environmental interferents on kinesin-powered molecular shuttles

Biomolecular motor-powered active transport represents an alternate means for analyte processing in nanoscale biosensors and bioanalytical devices. For example, a prototype "smart dust" biosensor has recently been reported in which the motor protein kinesin processes antibody-functionalized microtubules (MTs) to capture and separate optically tagged protein analytes. A potential limitation of this technology, however, involves the inhibition of transport function by interfering compounds that may be present in raw samples. Here we characterized the response of kinesin-MT transport to a range of potential interferents including solvents, acids, oxidizers, and environmental contaminants. The results of kinesin motility assays suggest that, among the tested interferents, only acetic acid and sodium hypochlorite adversely affected MT transport, primarily due to depolymerization of MT filaments. While negative effects were not observed for the remaining compounds tested, enhancement in motility was observed in the presence of acetone, antifreeze, and organic matter. Overall, the data suggest that kinesin-MT transport is resilient against a variety of common interferents, but primarily susceptible to failure due to significant changes in pH or the presence of an oxidizer.     

Enhancement of survival of probiotic and non-probiotic lactic acid bacteria by yeasts in fermented milk under non-refrigerated conditions

The effects of yeasts on the survival of probiotic and non-probiotic lactic acid bacteria (LAB) were studied in fermented milk under non-refrigerated conditions (30 °C) with a view to develop ambient-stable fermented milk with live LAB. Five yeasts tested (Saccharomyces bayanus, Williopsis saturnus var. saturnus, Yarrowia lipolytica, Candida kefyr and Kluyveromyces marxianus) enhanced the survival of Lactobacillus bulgaricus (but not Streptococcus thermophilus) in a mixed yoghurt culture in yoghurt by ~ 10² to 10⁵-fold. Seven yeasts examined (Candida krusei, Geotrichum candidum, Pichia subpelliculosa, Kloeckera apiculata, Pichia membranifaciens, Schizosaccharomyces pombe and Y. lipolytica) improved the survival of Lactobacillus rhamnosus in fermented milk by ~ 10³ to 10⁶-fold. W. saturnus var. saturnus enhanced the survival of Lactobacillus acidophilus, L. rhamnosus (probiotic) and Lactobacillus reuteri by up to 10⁶-fold, but the same yeast failed to improve the survival of Lactobacillus johnsonii (probiotic), S. thermophilus and L. bulgaricus in fermented milk. These results provide definitive evidence that yeasts possess stability-enhancing effects on LAB and that the specific effects of yeasts on LAB stability vary with yeasts as well as with LAB. However, the molecular mechanism of such interaction of yeasts with LAB remains to be found.     

Surveillance of Enteric Viruses and Microbial Indicators in the Eastern Oysters (Crassostrea virginica) and Harvest Waters along Louisiana Gulf Coast

Noroviruses are the most common causative agent of viral gastroenteritis in humans, and are responsible for major foodborne illnesses in the United States. Filter‐feeding molluscan shellfish exposed to sewage‐contaminated waters bioaccumulate viruses, and if consumed raw, transmit the viruses to humans and cause illness. We investigated the occurrence of norovirus GI and GII and microbial indicators of fecal contamination in the eastern oysters (Crassostrea virginica) and water from commercial harvesting areas along the Louisiana Gulf Coast (January to November of 2013). Microbial indicators (aerobic plate count, enterococci, fecal coliforms, Escherichia coli, male‐specific coliphages, and somatic coliphages) were detected at the densities lower than public health concerns. Only one oyster sample was positive for norovirus GII at 3.5 ± 0.2 log₁₀ genomic equivalent copies/g digestive tissues. A stool specimen obtained from an infected individual associated with a norovirus outbreak and the suspected oysters (Cameron Parish, La., area 30, January 2013) were also analyzed. The norovirus strain in the stool belonged to GII.4 Sydney; however, the oysters were negative and could not be linked. In general, no temporal trend was observed in the microbial indicators. Low correlation among bacterial indicators was observed in oysters. Strongest correlations among microbial indicators were observed between enterococci and fecal coliforms (r = 0.63) and between enterococci and E. coli (r = 0.64) in water (P < 0.05); however, weak correlations were found in oysters (r < 0.45) and between oysters and harvest water (r ≤ 0.36, P > 0.05). Our results emphasize the need for regular monitoring of pathogenic viruses in commercial oyster harvesting areas to reduce the risks of viral gastroenteritis incidences.     

Process engineering for bioflavour production with metabolically active yeasts – a mini‐review

Flavours are biologically active molecules of large commercial interest in the food, cosmetics, detergent and pharmaceutical industries. The production of flavours can take place by either extraction from plant materials, chemical synthesis, biological conversion of precursor molecules or de novo biosynthesis. The latter alternatives are gaining importance through the rapidly growing fields of systems biology and metabolic engineering, giving efficient production hosts for the so‐called 'bioflavours', which are natural flavour and/or fragrance compounds obtained with cell factories or enzymatic systems. Yeasts are potential production hosts for bioflavours. In this mini‐review, we give an overview of bioflavour production in yeasts from the process‐engineering perspective. Two specific examples, production of 2‐phenylethanol and vanillin, are used to illustrate the process challenges and strategies used. Copyright © 2014 John Wiley & Sons, Ltd.     

Differential killing activity of cetylpyridinium chloride with or without bacto neutralizing buffer quench against firmly adhered Salmonella gaminara and Shigella sonnei on cut lettuce stored at 4 degrees C

Cetylpyridinium chloride (CPC) activity was quenched with Bacto neutralizing buffer on inoculated cut iceberg lettuce. This protocol permitted comparison of the numbers of Salmonella Gaminara- or Shigella sonnei-inoculated cells on lettuce that survived 1 min of CPC treatment. Cut lettuce was inoculated with about 6 log of Salmonella or 9 log of Shigella and stored in Whirl-Pak bags at 4 degrees C for up to 4 days. Loosely adhered pathogen cells were washed off before CPC treatment. Firmly adhered cells of Salmonella Gaminara or S. sonnei on cut iceberg lettuce survived treatment with CPC even at the 0.4% CPC level if the CPC activity was quenched after 1 min by adding Bacto neutralizing buffer. The results confirm that there is extended killing activity of residual CPC against Salmonella Gaminara or S. sonnei if the residual CPC remaining in contact with the lettuce after the initial 1-min wash is not quenched. The CPC treatment was useful in reducing the numbers of these target pathogens on lettuce.     

Effectiveness of icing as a postharvest treatment for control of Vibrio vulnificus and Vibrio parahaemolyticus in the eastern oyster (Crassostrea virginica)

The focus of this research was to investigate the efficacy of icing as a postharvest treatment for reduction of the levels of Vibrio vulnificus and Vibrio parahaemolyticus in commercial quantities of shellstock oysters. The experiments were conducted in June and August of 2006 and consisted of the following treatments: (i) on-board icing immediately after harvest; (ii) dockside icing approximately 1 to 2 h prior to shipment; and (iii) no icing (control). Changes in the levels of pathogenic Vibrio spp. during wholesale and retail handling for 2 weeks postharvest were also monitored. On-board icing achieved temperature reductions in all sacks in accordance with the National Shellfish Sanitation Program standard, but dockside icing did not meet this standard. Based on one-way analysis of variance, the only statistically significant relationship between Vibrio levels and treatment occurred for samples harvested in August; in this case, the levels of V. vulnificus in the noniced oysters were significantly higher (P < 0.05) than were the levels in the samples iced on-board. When analyzing counts over the 14-day storage period, using factorial analysis, there were statistically significant differences in V. vulnificus and V. parahaemolyticus levels by sample date and/or treatment (P < 0.05), but these relationships were not consistent. Treated (iced) oysters had significantly higher gaping (approximately 20%) after 1 week in cold storage than did noniced oysters (approximately 10%) and gaping increased significantly by day 14 of commercial storage. On-board and dockside icing did not predictably reduce the levels of V. vulnificus or V. parahaemolyticus in oysters, and icing negatively impacted oyster survival during subsequent cold storage.     

Patterns of eye movements during parallel and serial visual search tasks.

In 2 experiments with a total of 24 undergraduates, eye movements were monitored while Ss performed parallel and serial search tasks. In Exp 1a, Ss searched for an "O" among "X"s (parallel condition) and for a "T" among "L"s (serial condition). In the parallel condition of Exp 1b, "Q" was the target and "O"s were distractors; in the serial condition, these stimuli switched roles. Displays contained 1, 12, or 24 stimuli, with both target-present and target-absent trials. RT and eye-movement measures (number of fixations, saccadic error, and latency to move) indicated that search efficiency was greatest in the parallel conditions, followed by the serial condition of Exp 1a and, finally, by the serial condition of Exp 1b. This suggests that eye movements are correlated with the attentional processes underlying visual search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcoholism, aging, and functional cerebral asymmetries.

Reviews research concerning the possible relationship between cognitive decline and abnormal hemispheric asymmetries in alcoholic and aging individuals. Because the deteriorative effects of alcoholism on the central nervous system have suggested greater visuospatial than language-related functional impairments, numerous investigators had hypothesized that right-hemisphere integrity may be selectively disrupted (rather than the left hemisphere). Furthermore, performance on diverse perceptual and cognitive tests used to measure right-hemisphere functions in alcoholics had been observed to decline with normal chronological aging as well, thereby raising the possibility that certain neuropsychological deficits associated with alcoholism (presumably related to right-hemispheric decline) are identical to those associated with aging. However, an extensive review of empirical research findings on cerebral asymmetries both in alcoholics and in aging individuals suggested that their patterns of functional laterality are similar to those of normal controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term semantic priming: A computational account and empirical evidence.

Semantic priming is traditionally viewed as an effect that rapidly decays. A new view of long-term word priming in attractor neural networks is proposed. The model predicts long-term semantic priming under certain conditions. That is, the task must engage semantic-level processing to a sufficient degree. The predictions were confirmed in computer simulations and in 3 experiments. Experiment 1 showed that when target words are each preceded by multiple semantically related primes, there is long-lag priming on a semantic decision task but not on a lexical-decision task. Experiment 2 replicated the long-term semantic priming effect for semantic decisions with only one prime per target. Experiment 3 demonstrated semantic priming with much longer word lists at lags of 0, 4, and 8 items. These are the first experiments to demonstrate a semantic priming effect spanning many intervening items and lasting much longer than a few seconds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)