Assessing airborne bacteria abundance in sea foam aerosol

The influence of bacterial cell concentration on estimates of the number of binding sites and the affinity for the adsorption of a strain of Streptococcus sanguis to saliva-treated hydroxyapatite was determined, and the possible presence of multiple binding sites for this organism was tested. The range of concentrations of available bacteria varied from 4.7 x 10(6) to 5,960 x 10(6) cells per ml. The numbers of adsorbed bacteria increased over the entire range tested, but a suggestion of a break in an otherwise smooth adsorption isotherm was evident. Values for the number of binding sites and the affinity varied considerably depending upon the range of available bacterial concentrations used to estimate them; high correlation coefficients were obtained in all cases. The use of low bacterial cell concentrations yielded lower values for the number of sites and much higher values for the affinity constant than did the use of high bacterial cell concentrations. When data covering the entire range of bacterial concentrations were employed, values for the number of sites and the affinity were similar to those obtained by using only high bacterial cell concentrations. The simplest explanation for these results is that there are multiple binding sites for S. sanguis on saliva-treated hydroxyapatite surfaces. When present in low concentration, the streptococci evidently attach to more specific high-affinity sites which become saturated when higher bacterial concentrations are employed. The possibility of multiple binding sites was substantiated by comparing estimates of the adsorption parameters from a computer-simulated isotherm with those derived from the experimentally generated isotherm. A mathematical model describing bacterial adsorption to binary binding sites was further evidence for the existence of at least two classes of binding sites for S. sanguis. Far fewer streptococci adsorbed to experimental pellicles prepared from saliva depleted of bacterial aggregating activity when low numbers of streptococci were used, but the magnitude of this difference was considerably less when high streptococcal concentrations were employed. This suggests an association between salivary components which possess bacterial-aggregating activity and bacterial adsorption to high-affinity specific binding sites on saliva-treated hydroxyapatite surfaces.

Pang, H.; Ingelido, P.; Hirst, B.; Pflaumer, J.; Witt, A.; Zaman, A., and Aiello, J., 2017. Water quality condition and assessment within the Barnegat Bay watershed between 2011 and 2015. In: Buchanan, G.A.; Belton, T.J., and Paudel, B. (eds.), A Comprehensive Assessment of Barnegat Bay–Little Egg Harbor, New Jersey. To address the ecological health of Barnegat Bay in New Jersey, a comprehensive water monitoring program has been conducted within the Barnegat Bay watershed by the New Jersey Department of Environmental Protection and multiple partners since June 2011. Barnegat Bay and its tributaries were evaluated for multiple water quality metrics and from various perspectives. The nutrient concentrations and loadings from the tributaries in the northern watershed are higher than those from the tributaries in the southern portion of the watershed. Within Barnegat Bay, higher nitrogen concentrations were observed in the northern portion, while higher total phosphorus (TP) concentrations occurred i...

Article Figures and data Abstract eLife digest Introduction Results Discussion Materials and methods References Decision letter Author response Article and author information Metrics Abstract How the nervous system internally represents environmental food availability is poorly understood. Here, we show that quantitative information about food abundance is encoded by combinatorial neuron-specific gene-expression of conserved TGFβ and serotonin pathway components in Caenorhabditis elegans. Crosstalk and auto-regulation between these pathways alters the shape, dynamic range, and population variance of the gene-expression responses of daf-7 (TGFβ) and tph-1 (tryptophan hydroxylase) to food availability. These intricate regulatory features provide distinct mechanisms for TGFβ and serotonin signaling to tune the accuracy of this multi-neuron code: daf-7 primarily regulates gene-expression variability, while tph-1 primarily regulates the dynamic range of gene-expression responses. This code is functional because daf-7 and tph-1 mutations bidirectionally attenuate food level-dependent changes in lifespan. Our results reveal a neural code for food abundance and demonstrate that gene expression serves as an additional layer of information processing in the nervous system to control long-term physiology. https://doi.org/10.7554/eLife.06259.001 eLife digest To maximize their chances of survival, animals need to be able to sense changes in the abundance of food in their environment and respond in an appropriate manner. The nervous system is able to sense cues from the environment and coordinate responses in the whole organism, but it is not clear how this leads to long-term changes in the organism's biology. In nematode worms, two genes called daf-7 and tph-1 appear to be involved in connecting the sensing of food availability with changes in the biology of the organism. The daf-7 gene encodes a hormone, while tph-1 encodes an enzyme that makes a neurochemical called serotonin. Here, Entchev, Patel, Zhan et al. found that daf-7 and tph-1 genes are active in three pairs of neurons in nematode worms. The experiments show that these neurons collectively form a circuit that carries information about the abundance of food, which leads to changes in how long the worms live. When this circuit was disrupted by removing these genes, the worms' ability to adjust their lifespan in response to changes in the availability of food was weakened, likely because they were unable to sense food. The experiments also show that the circuit regulates itself, largely because daf-7 and tph-1 are able to control each-other's activity. Together, these results suggest that changing the activity of certain genes in neurons enables nematode worms to alter their biology in response to changes in the availability of food. Neurons in the brain use electrical activity to communicate and process information and Entchev, Patel, Zhan et al.'s findings imply that gene activity can also perform a similar role. https://doi.org/10.7554/eLife.06259.002 Introduction All organisms need to accurately assess their environment to respond to changes that impact their survival. Environmental changes such as food availability can lead to alterations in organismal physiology, such as stress resistance and metabolic states that have consequences for clinically important outputs such as disease progression, health, fecundity and lifespan (Libert and Pletcher, 2007). Many conserved genetic mechanisms that govern these alterations to physiology have been identified (Libert and Pletcher, 2007; Berthoud and Morrison, 2008; Rother et al., 2008; Alcedo et al., 2010; Koch and Horvath, 2014). Yet, how these genetic pathways encode and process information about the environment to elicit physiological outputs in vivo is unclear at a quantitative and mechanistic level, despite their importance for health and disease. In animals, the nervous system is the central site for processing sensory information and coordinates organism-wide responses to changing conditions. Food availability is a critical environmental variable that modulates metabolism and other physiological outputs via neuroendocrine circuits (Berthoud and Morrison, 2008; Rother et al., 2008; Alcedo et al., 2010; Koch and Horvath, 2014). In contrast to well-studied sensory modalities such as vision and olfaction (Baier, 2013; Wilson, 2013), where neural processing occurs on short timescales using electrical signals, how food availability is internally represented across a broad range of inputs to regulate long-term, food-related physiological responses remains virtually unknown. A particularly interesting food-related response is the role of dietary restriction (DR) in modulating lifespan in diverse species (Bishop and Guarente, 2007; Mair and Dillin, 2008; Fontana et al., 2010; Alic and Partridge, 2011). DR occurs through changes that likely happen over long timescales (hours to days), unlike fast behavioral responses to visual or olfactory cues. Neural gene expression also occurs over long timescales (minutes to hours) and is thus well suited for functionally encoding food abundance during DR. In Caenorhabditis elegans, daf-7 and tph-1 are conserved components of neural TGFβ and serotonin signaling pathways, respectively, and are associated with food sensing and modulation of organismal physiology. daf-7 encodes a TGFβ family member (Ren et al., 1996), while tph-1 encodes tryptophan hydroxylase, the rate-limiting enzyme for serotonin synthesis (Sze et al., 2000). In C. elegans, TGFβ and serotonin signaling affect lifespan and metabolism, consistent with conserved roles from invertebrates to mammals (Sze et al., 2000; Ashrafi, 2007; Murakami and Murakami, 2007; Petrascheck et al., 2007; Shaw et al., 2007; Brown and Schneyer, 2010; Oury and Karsenty, 2011). tph-1 and daf-7 are expressed in an environmentally responsive manner in specific neurons with food-related functions (Ren et al., 1996; Schackwitz et al., 1996; Sze et al., 2000; Zhang et al., 2005; Chang et al., 2006; Liang et al., 2006; Greer et al., 2008; Pocock and Hobert, 2010). daf-7 is expressed in the ASI sensory neurons, whose activities are responsive to bacterial food (Ren et al., 1996; Gallagher et al., 2013; Zaslaver et al., 2015). Starvation reduces daf-7 expression in ASI, and laser ablations of ASI extend lifespan, consistent with the role of daf-7 and other ASI-expressed genes in modulating lifespan (Ren et al., 1996; Alcedo and Kenyon, 2004; Bishop and Guarente, 2007). tph-1 is expressed in the NSM foregut neurons, the ADF sensory neurons, and the HSN motorneurons involved in egg-laying (Sze et al., 2000). Both serotonin signaling mutants and NSM ablation affect food-modulated locomotion, consistent with the idea that serotonin from NSM acts in this food-related response (Sawin et al., 2000). In the food-responsive ADF neurons (Zaslaver et al., 2015), tph-1 expression is responsive to pathogenic bacteria and starvation, to respectively mediate aversive olfactory plasticity and stress responses (Zhang et al., 2005; Liang et al., 2006). daf-7 and tph-1 are therefore strong candidates for mediating the link between environmental cues and longevity. Nonetheless, how these genes cooperate to quantitatively encode a broad range of food levels to modulate lifespan is unknown. Gene-expression responses to food cues have largely been studied as ON/OFF switches to the presence or absence of food (Zinke et al., 2002; Baugh et al., 2009). Because food abundance is a continuous variable, we sought to understand how expression of tph-1 and daf-7 could allow animals to distinguish multiple food levels. Furthermore, gene expression is inherently variable (Eldar and Elowitz, 2010), but this property is rarely studied in vivo in multicellular animals; thus we also sought to determine how gene-expression variability affects the ability of the worm to encode its environment. Here we show that daf-7 and tph-1 expression in three pairs of neurons forms a distributed circuit that quantitatively encodes food abundance and mediates dietary effects on lifespan in C. elegans. Specific disruptions to this circuit resulted in corresponding attenuation in the ability to discriminate between food levels in both the gene-expression code and lifespan output. We found that this circuit tunes its own accuracy, largely via the regulation of the dynamic range and variability of food-responsive gene expression by tph-1 and daf-7 signalling, respectively. Our work suggests that neural regulation of gene expression in conserved pathways can couple environmental sensation to physiological output, and highlights a novel mechanism for information processing by the nervous system to impact physiology. Results Two neuronal genes mediate bidirectional effects of DR on lifespan During DR, lifespan increases as food levels are decreased from ad libitum conditions until reaching a maximum, beyond which further food reduction lowers lifespan (Bishop and Guarente, 2007; Mair and Dillin, 2008; Fontana et al., 2010; Alic and Partridge, 2011). To fully understand the response to food levels that C. elegans might encounter in the wild (Felix and Duveau, 2012), we modified a well-established DR protocol (Greer et al., 2007) (Figure 1A) to measure the lifespans of wildtype animals shifted as day 2 adults to 19 concentrations of the Escherichia coli food source across ∼11 orders of magnitude (Figure 1B, Figure 1—figure supplement 1 and Figure 1—source data 1). We inhibited progeny production with egg-5(RNAi) (Figure 1A) to prevent matricide due to internal hatching at low food levels. This treatment does not affect the lifespan response to food; similar responses were observed in wildtype animals without egg-5(RNAi) (Figure 1—figure supplement 1), and are found in the literature where similar subsets of food ranges were tested using other DR protocols (below). Figure 1 with 2 supplements see all Download asset Open asset Two neuronal genes, daf-7 and tph-1, shape a complex, multiphasic relationship between lifespan and food availability. (A) Protocol for maintaining animals at different food levels for lifespan and imaging experiments. Effects of initiating different dietary restriction (DR) on different days are shown in Figure 1—figure supplement 1A,B. (B) Mean lifespan of wildtype worms subjected to 19 food levels ranging from 0–3.5 × 1010 bacterial cells/ml at 20°C. Points denoting key features in the food response and used as food conditions in subsequent experiments are highlighted. Figure 1—figure supplement 1D shows that these lifespan responses have similar shapes across different temperatures. The lifespan data are shown in Figure 1—source data 1. (C) Mean lifespans of wildtype and mutant animals across the six food levels indicated in (B) show that loss of tph-1 and daf-7 preserves the pattern but attenuates the range of the lifespan response. Genotypes are indicated by the legends below (E) and (F). The lifespan data are shown in Figure 1—source data 2, and statistical comparisons between the different genotypes and food levels are shown in Figure 1—source data 3. (D) tph-1 and daf-7 modulation of lifespan is bidirectional and their epistatic relationship is food-specific. The epistatic interaction between the two genes in the tph-1(−); daf-7(−) double mutant differs depending on food level. The double mutant resembled the tph-1(−) single mutant in the absence of a bacterial food source and resembled the daf-7(−) single mutant at a high bacterial food concentration. (E) Range of food-induced lifespan modulation for each genotype. Range is defined by the difference between the highest and lowest mean lifespan response across the six food levels. (F) Average of the mean lifespan responses across all food levels for each genotype reveals a consistent, food-independent baseline lifespan response. The schedule for transferring animals to different conditions in these lifespans are shown in Figure 1—figure supplement 2. https://doi.org/10.7554/eLife.06259.003 Figure 1—source data 1 Summary of wild type lifespan outputs under the full range of food levels tested. https://doi.org/10.7554/eLife.06259.004 Download elife-06259-fig1-data1-v1.xlsx Figure 1—source data 2 Summary of wild type and mutant lifespan outputs under six selected food levels. https://doi.org/10.7554/eLife.06259.005 Download elife-06259-fig1-data2-v1.xlsx Figure 1—source data 3 Statistical significance of lifespan modulation across food levels and genetic backgrounds. https://doi.org/10.7554/eLife.06259.006 Download elife-06259-fig1-data3-v1.xlsx We uncovered a multiphasic relationship between bacterial abundance and longevity that is more complex than previously reported with smaller concentration ranges (Figure 1B) (Greer et al., 2007; Greer and Brunet, 2009; Ching et al., 2010). We found that lifespan increased and then decreased as bacterial concentration was reduced from the highest level, forming a DR response consistent with prior reports at high food ranges (Bishop and Guarente, 2007; Panowski et al., 2007; Greer and Brunet, 2009; Mair et al., 2009; Ching et al., 2010). Surprisingly, upon further reduction, lifespan increased again till a plateau was reached, suggesting that the initial decrease was not due to limiting nutrients. The longest lifespans occurred in the absence of bacteria, where the magnitudes of these effects were consistent with published dietary deprivation experiments (Kaeberlein et al., 2006; Lee et al., 2006). This relationship between lifespan and food abundance was maintained across temperatures (Figure 1—figure supplement 1), suggesting a robust food-sensing process. This multiphasic food response may reflect trade-offs between multiple food-regulated processes as previously discussed (Kaeberlein et al., 2006; Lee et al., 2006). Here we used the complex lifespan response as a functional basis for understanding how neuronal gene expression could encode food abundance. To understand how the multiphasic lifespan response to food abundance is regulated, we measured the lifespan of daf-7 and tph-1 null mutants across six bacterial concentrations that captured the complexity of broad-range DR (circled in Figure 1B). Prior studies suggested that daf-7 and tph-1 mediate lifespan extension (Murakami and Murakami, 2007; Shaw et al., 2007; van der Goot et al., 2012). We showed that their effects were in fact bidirectional: these genes could either extend or reduce lifespan in a food-specific manner (Figure 1C, Figure 1—source data 2, 3). Both single mutants had reduced lifespans at low food levels and increased lifespan at 6 × 108 cells/ml in comparison to wildtype; additionally, daf-7(−) mutants were long-lived at the highest food level (Figure 1C). The magnitude of lifespan changes we observed at high food levels (1 × 1010 cells/ml) were comparable to prior studies performed at ad libitum food conditions (Murakami and Murakami, 2007; Shaw et al., 2007). Intriguingly, tph-1 and daf-7 influenced the longevity response more strongly at low and high bacterial concentrations respectively (Figure 1D), suggesting that they act at different but overlapping ranges of food. Furthermore, the double mutant resembled the tph-1(−) mutant at low bacterial levels and the daf-7(−) mutant at high bacterial levels (Figure 1D), suggesting that these genes act in parallel rather than in a linear pathway. Together, these phenotypes indicate that daf-7(−) and tph-1(−) mutants were neither intrinsically long- nor short-lived; instead, their phenotypes and genetic interactions were modulated by extensive gene-environment interactions. Rather than altering the basic pattern of the lifespan response to food, loss of tph-1 or daf-7, either alone or in combination, dampened food responsiveness by bidirectionally attenuating extension and reduction of lifespan due to DR (Figure 1C,D). This effect was manifested in the diminished range of lifespans across all food levels in both the daf-7(−) and tph-1(−) single mutants, which was further reduced in the double mutant (Figure 1E). This result also supports the idea that these genes act in parallel pathways. Furthermore, the mean lifespan across all food levels were similar in all the genotypes tested (Figure 1F), suggesting that mutations in tph-1 and daf-7 lowered the food-responsive component of longevity around a consistent, food-independent lifespan that may be specified by other environmental parameters such as temperature (Figure 1E and Figure 1—figure supplement 1). This bidirectional dampening of the food response and preservation of an underlying lifespan differs from previously described DR regulators, such as aak-2, daf-16, pha-4 and skn-1, whose mutants abolish DR-mediated lifespan extension (Bishop and Guarente, 2007; Greer et al., 2007; Panowski et al., 2007). Thus, tph-1 and daf-7 mutants reveal a previously unobserved DR phenotype, and our results suggest that these genes mediate a bidirectional lifespan response to DR. Neuronal expression of daf-7 and tph-1 encodes food abundance tph-1 is expressed in the ADF sensory neurons, the NSM neurons within the foregut, and the hermaphrodite-specific HSN motor neurons (Sze et al., 2000). daf-7 is expressed in a single pair of ASI sensory neurons (Ren et al., 1996; Schackwitz et al., 1996). To determine whether tph-1 and daf-7 act in these neurons to modulate lifespan, we expressed these genes in specific neurons and tested their ability to rescue the lifespan phenotypes in the tph-1(−); daf-7(−) double mutant. Expression of tph-1 in either ADF or NSM neurons (Figure 2A–C) or of daf-7 in ASI neurons (Figure 2D,E) could rescue the lifespan phenotypes at low and high food levels, respectively. These results indicate that the activity of tph-1 and daf-7 in these respective neurons are relevant to lifespan modulation. Figure 2 Download asset Open asset Neuron-specific rescue of lifespan phenotypes. (A) Lifespan outcomes of wildtype, tph-1(−) and daf-7(−) single mutants and the tph-1(−); daf-7(−) double mutant indicates that the double mutant closely resembles the tph-1(−) mutant in the absence of a bacterial food source. (B) In the absence of bacterial food, restoration of tph-1 activity in the NSM neurons via the expression of a tph-1 cDNA driven by the ceh-2 promoter rescues the lifespan reduction observed in the tph-1(−); daf-7(−) double mutants. (C) Restoration of tph-1 expression in the ADF neurons via the srh-142 promoter also shows reversal of the lifespan reduction. (D) Lifespan outcomes of wildtype, tph-1(−) and daf-7(−) single mutants and the tph-1(−); daf-7(−) double mutant indicates that the double mutant closely resembles the daf-7(−) mutant at a high concentration of the bacterial food source. (E) At high food level, restoration of daf-7 expression in the ASI neurons via the expression of daf-7 under the gpa-4 promoter reverses the lifespan extension observed in the tph-1(−); daf-7(−) double mutants. All comparisons are drawn against non-transgenic siblings of animals bearing the extrachromosomal array of interest. https://doi.org/10.7554/eLife.06259.009 Previous studies showed that daf-7 and tph-1 expression are regulated by environmental cues (Ren et al., 1996; Schackwitz et al., 1996; Sze et al., 2000; Zhang et al., 2005; Chang et al., 2006; Liang et al., 2006; Greer et al., 2008; Pocock and Hobert, 2010). However, their expression profiles over a broad range of inputs remain unknown because manual studies limit the number of animals and environmental conditions that can be feasibly studied in a consistent way. To overcome these limitations, we used an automated, high-throughput microfluidic-based platform (Figure 3A and Figure 3—figure supplement 1) (Chung et al., 2008; Crane et al., 2012) for quantitative large-scale imaging of individual worms bearing single-copy fluorescent transcriptional reporters for both tph-1 and daf-7 (Ptph-1::mCherry and Pdaf-7::Venus) across different food levels (Figure 3B). For brevity, we refer to these reporter activities as tph-1 and daf-7 expression. Our reporters contain the same regulatory regions as published reporters that have been well validated, and show identical expression patterns (Ren et al., 1996; Schackwitz et al., 1996; Sze et al., 2000; Zhang et al., 2005; Chang et al., 2006; Liang et al., 2006; Greer et al., 2008; Pocock and Hobert, 2010) (Figure 3B). Starvation, hypoxia, or pathogenic bacteria alter both tph-1 reporter expression and serotonin levels (Zhang et al., 2005; Liang et al., 2006; Pocock and Hobert, 2010), while corresponding changes occur in daf-7 RNA levels and daf-7 reporter expression (Ren et al., 1996). These published results indicate that tph-1 and daf-7 reporters are faithful readouts for the expression of their respective genes (see ‘Materials and methods’ for additional details on reporter validation). Figure 3 with 1 supplement see all Download asset Open asset High-throughput quantitative imaging of tph-1 and daf-7 fluorescent reporters reveals neuron-specific, graded expression responses to food level. (A) Microfluidic system enabling high-throughput, neuron-specific quantitative imaging of gene expression in a large number of individual animals. Animals are transferred from culture plates to a liquid suspension at day 6 of adulthood and then loaded into the device for imaging. Figure 3—figure supplement 1 shows an overview of this imaging system. (B) Representative merged fluorescent image of transgenic worm with red and green fluorescent reporters for tph-1 and daf-7 transcriptional activity. Shapes indicate locations and identities of specific neurons. (C) Mean expression profiles of tph-1 in NSM (Ptph-1NSM) and ADF (Ptph-1ADF), and daf-7 in ASI (Pdaf-7ASI) across six different food levels are neuron-specific and largely non-monotonic. Measurements are normalized to the highest mean expression response observed in each respective neuron; error bars are SEM. (D) Distribution of the expression responses of tph-1 in NSM and ADF and daf-7 in ASI at different food levels. Means are indicated by the solid lighter-shade lines behind the distributions. Dashed line denotes the highest mean expression for each neuron, which was used for normalization. https://doi.org/10.7554/eLife.06259.010 We measured tph-1 expression levels in both NSM and ADF, and daf-7 in ASI, in animals exposed to the same six food levels that define our complex DR response (Figure 3C). Remarkably, we found that each neuron type had a specific pattern of activity across the six food levels (Figure 3C). Even with respect to a single gene, tph-1, the expression response in NSM differed from that in ADF, suggesting non-redundant roles of NSM and ADF in encoding bacterial abundance. Consistent with low tph-1 expression in the absence of food (Figure 3C), serotonin levels were reduced in NSM and ADF after starvation (‘Materials and methods’ and Liang et al., 2006). Notably, the responses of tph-1 in NSM and daf-7 in ASI were non-monotonic, prohibiting unique representation of the food level using either of these readouts The dynamic range and variability of the three expression patterns also suggesting different the sensory from food in different neurons (Figure the of reporter for each neuron type shifted in a graded manner across the six bacterial concentrations (Figure that the expression of tph-1 and daf-7 could provide information about a continuous range of environmental inputs for individual animals. This graded response with pathways, such as signalling, that outputs with a number of where the population to changing environmental conditions by of from to 1996). gene expression may be used to internally environmental conditions and mediate long-term physiological outputs such as we to expression in individual neurons with lifespan across food levels. We found that the expression levels of the individual genes in each neuron alone were to either food inputs or lifespan outputs (Figure largely due to expression and lifespan responses 3C). However, encoding across multiple neurons can the by animals to use a combinatorial to internally environmental conditions with (Figure Figure Download asset Open asset The of all neuronal gene-expression readouts a unique internal representation of food levels. (A) between individual gene-expression profiles and the lifespan responses across the six food levels indicates that the individual readouts are to lifespan responses. (B) The of tph-1 in NSM (Ptph-1NSM) and ADF and daf-7 in ASI (Pdaf-7ASI) a encoding of both food inputs and lifespan (C) The ability of expression and lifespan readouts to respond to and food conditions can be by using the readouts of to the food conditions. The results can be represented by where the in each indicate the with which are for a food level. readouts result in high represented by a overlapping response profiles result in low represented by a (D) the of tph-1 and daf-7 readouts or in similar encoding to that of lifespan outputs in wildtype animals. To assess the accuracy of the internal representation of food levels on the graded combinatorial expression of tph-1 and daf-7 in wildtype animals, we a (Figure and the gene-expression we this to the food level that individual animals were exposed This into the of gene and thus both and variance to decreased between the from different food levels leads to increased accuracy (Figure We neuronal encoding with a to the population of expression data at each food level. We food on expression in and then to the food level to determine the accuracy of the gene-expression responses. The results were as the of each food the food for each population (Figure the expression were distinct across food levels, a was in a strongly (Figure the then the food level was and the in the were to the number of food conditions tested (Figure expression data from ADF or ASI we showed that each neuronal had (Figure When neuron pairs were and particularly all three neuron pairs were the accuracy (Figure This result suggests that non-redundant encoding by each neuron pair the accuracy of the this system was at the highest and lowest food levels, consistent with the and of C. elegans in the wild (Felix and Duveau, 2012). the bacterial level, 6 × 108 where we observed the lowest lifespan, also showed a the graded and encoding may allow certain food levels, the ability was also by in the responses. To determine the accuracy of gene expression was for modulating lifespan, we how accurately the lifespan could be used to the food level using a similar This is important because the accuracy of the for the accuracy in the internal the accuracy of both the representation and be that the representation carries information for the output. In this we whether lifespan could also be used to the food level by an using on the of our Remarkably, the accuracy of lifespan was similar to that of gene expression (Figure that

Unit layout affects every aspect of intensive care services, including patient safety. A previous study has shown that patients admitted to beds adjacent to the sink and to the door of a large bayroom had the highest number of positive blood cultures and the highest blood culture incidence density, respectively. The present study measures microbial air contamination in a medical intensive care unit of a medical center in central Taiwan. Of the 17 rooms, 8 rooms with distinct physical environmental characteristics were selected. Sampling tests were conducted between December 2013 and February 2014 with a microbial air sampler (MAS-100NT). TSA was used for bacteria collection and DG18 for fungi collection. The overall average bacterial and fungal concentrations were 83CFU/m<sup>3</sup> and 69CFU/m<sup>3</sup>, respectively. The ranges were between 8-354 CFU/m<sup>3</sup> and 0-1468 CFU/m<sup>3</sup>, respectively. A significant difference was found in the bacterial concentration (p=.005) between different room locations. The highest concentration was found in the rooms located at the front end of the circulation (99 CFU/m<sup>3</sup>), while the lowest was found in the rooms located at the rear end of the circulation (55CFU/m<sup>3</sup>). Differences in fungal concentrations for different room locations did not reach statistical significance. In addition, differences in bacterial and fungal concentrations for rooms with different sink locations did not reach statistical significance. Even though the microbial concentrations generally complied with standards, the results may help designers and hospital administrators develop a healthier environment for patients.

Unit layout affects every aspect of intensive care services, including patient safety. A previous study has shown that patients admitted to beds adjacent to the sink and to the door of a large bayroom had the highest number of positive blood cultures and the highest blood culture incidence density, respectively. The present study measures microbial air contamination in a medical intensive care unit of a medical center in central Taiwan. Of the 17 rooms, 8 rooms with distinct physical environmental characteristics were selected. Sampling tests were conducted between December 2013 and February 2014 with a microbial air sampler (MAS-100NT). TSA was used for bacteria collection and DG18 for fungi collection. The overall average bacterial and fungal concentrations were 83CFU/m<sup>3</sup> and 69CFU/m<sup>3</sup>, respectively. The ranges were between 8-354 CFU/m<sup>3</sup> and 0-1468 CFU/m<sup>3</sup>, respectively. A significant difference was found in the bacterial concentration (p=.005) between different room locations. The highest concentration was found in the rooms located at the front end of the circulation (99 CFU/m<sup>3</sup>), while the lowest was found in the rooms located at the rear end of the circulation (55CFU/m<sup>3</sup>). Differences in fungal concentrations for different room locations did not reach statistical significance. In addition, differences in bacterial and fungal concentrations for rooms with different sink locations did not reach statistical significance. Even though the microbial concentrations generally complied with standards, the results may help designers and hospital administrators develop a healthier environment for patients.

Diamondback terrapins as indicator species of persistent organic pollutants: Using Barnegat Bay, New Jersey as a case study

Erratum: High-Throughput Identification of Resistance to Pseudomonas syringae pv. Tomato in Tomato using Seedling Flood Assay.

With no acceptable method for collecting fresh rumen fluid from zoo ruminants, it was proposed that fecal bacterial concentrations may be correlated with rumen bacteria. If so, fecal bacterial concentrations could be used to study both the effects of diet on rumen bacteria as well as rumen abnormalities. Total and cellulolytic bacterial concentrations were determined in whole rumen contents and feces of sheep using a most-probable-number (MPN) assay. In a Latin square design, four crossbred ewes were fed diets of 100% long or chopped orchardgrass hay (OH) and 60% ground or whole shelled corn plus 40% chopped OH. In a second trial, the sheep were fed a pelleted complete feed at varying levels of intake i.e., control at 2.0% of body weight and at 1.8, 1.6, and 1.2% of body weight. Higher total rumen bacterial concentrations (P<0.01) were found on the high concentrate diets as compared with the high forage diets. Grinding the corn also increased total bacterial concentrations (P<0.05). Fecal concentrations of total bacteria were higher (P<0.01) with the high concentrate diets. Chopping the forage decreased the concentration of fecal cellulolytic bacteria (P<0.05) but had no effect on their concentration in the rumen. An inverse linear relationship (P<0.01) was observed between total bacterial concentrations in the feces and diet intake. Although relationships were observed between the rumen and feces for total and cellulolytic bacterial concentrations, they were dependent on diet, particle size, and level of intake. Thus, fecal bacterial concentrations cannot be used to reliably predict rumen bacterial concentrations. Zoo Biol 27:100-108, 2008. (c) 2008 Wiley-Liss, Inc.

<p indent="0mm">Indoor microbes have been listed in the category of indoor air pollutants by World Health Organization (WHO) in 1990. Exposure to a high concentration of airborne bioaerosol potentially causes adverse health effects, such as pneumonia, asthma, and allergies. People spend most of their time in residence in their life, so figuring out the characteristic of residential airborne microbes is very important for occupants’ health. However, previous studies mostly focused on indoor microorganisms in public buildings, while very little work has been done on the characteristics of indoor airborne bacteria and fungi in residence. In this study, we investigated the indoor airborne bacterial concentration, fungal concentration, and taxonomic diversity of residences in summer and winter among five different climate zones across China, as well as the community structure, and revealed the correlations between indoor airborne microbial characteristics (concentrations and taxonomic diversity) and geographical location by using polynomial fitting. Culturing and sequencing methods were combined in this study, for which we collected 376 culturable samples and 168 sequencing samples of bacteria and fungi each. We found the bacterial concentrations between summer and winter were significantly different in the hot summer &amp; cold winter climate zone and the hot summer &amp; warm winter climate zone, whereas there was no significant difference between different seasons among different climate zones for fungal concentrations. The bacterial concentrations in the hot summer &amp; cold winter zone (Nanjing, 875±553 CFU/m³) and hot summer &amp; warm winter (Shenzhen, 758±473 CFU/m³) were significantly higher than those in the other climate zones in summer (<italic>P </italic>&lt; 0.05); the lowest bacterial concentrations in winter were found in hot summer &amp; cold winter (Nanjing, 191±119 CFU/m³). For fungi, the highest concentrations were found in the severe cold climate zone (Harbin, 743±798 CFU/m³) and cold climate zone (Lhasa, 1369±1380 CFU/m³) in summer; while the highest was only found in the severe cold climate zone (Harbin, 654±493 CFU/m³) in winter. We also found that the bacterial diversity in the hot summer &amp; cold winter climate zone was significantly different between summer and winter; the fungi diversity in the hot summer &amp; cold winter climate zone and hot summer &amp; warm winter climate zones was significantly different between summer and winter. For bacteria, the lowest taxonomic diversity in summer was found in severe cold climate zone and the highest was found in hot summer &amp; cold winter climate zone; the lowest taxonomic diversity in winter was found in severe cold climate zone and hot summer &amp; cold winter climate zone. For fungi taxonomic diversity, the highest values were found in severe cold climate zone and hot summer &amp; cold winter climate zone in summer; the highest values were found in cold climate zone and hot summer &amp; warm winter climate zone in winter. We analyzed the community structure of bacteria and fungi at the phylum level. The TOP 4 bacterial species and TOP 3 fungal species between different climate zones in summer and winter were similar. The TOP 4 bacteria species in residences were <italic>Bacteroidetes</italic>, <italic>Proteobacteria</italic>, <italic>Firmicutes</italic>,<italic> </italic>and <italic>Actinobacteria</italic>. The TOP 3 fungi species were <italic>Ascomycota</italic>, <italic>Basidiomycota</italic>, and <italic>Zygomycota</italic>, except for Beijing, which is located in a cold climate zone. By analyzing the correlations between indoor microbial characteristics and geographical location, we found the variation of indoor microbial diversity with latitude was opposite in summer and winter. In summer, indoor bacterial concentrations and diversity first increased and then decreased with the increase of longitude, which was opposite to the trend of fungi. There was no correlation between winter bacterial concentrations and geographical location.

Effects of aerosol pollution on PM2.5-associated bacteria in typical inland and coastal cities of northern China during the winter heating season

Investigation into the optimal bacterial concentration for compressive strength enhancement of microbial concrete

Highly conductive electrolyte materials are an essential part of many electrochemical systems, such as fuel cells, solar cells, batteries, electrochromic devices, and next-generation renewable-energy sources. The growing diversity in batteries and electrochemical cells increases the demand for novel electrolyte materials. For instance, in solar-cell applications, an electrolyte material with high viscosity and low volatility is desirable, together with high ionic conductivity. Electrolytes can be solids, gels, or liquids depending on the application. Gel electrolytes are advantageous when the conductivity in the solid form is not sufficient or the leakage or vaporization of the liquid electrolyte is a problem. Gel electrolytes can be aqueous or non-aqueous depending on the application type. While in some battery systems aqueous gel electrolytes have no use—for example, in Li ion batteries—they can be used in many rechargeable batteries, electrochemical capacitors, solar cells, and so on. Liquid-crystal gel electrolytes have also been investigated and are considered to be an important class of ordered materials for the above applications. A lyotropic liquid-crystalline (LLC) mesophase is formed by two main constituents: an amphiphile and a solvent. Common solvents are water, organic liquids, or ionic liquids. LLC-based electrolytes offer many advantages, like rigidity and high ionic mobility and can be an alternative to polymer electrolytes. Solvent-free LC systems (thermotropic LC) usually have low ionic conductivities at room temperature, typically around 10 6 Scm , whereas solvent-containing LLC systems have room-temperature ionic conductivities around 10 3 Scm . Usually high ionic conductivity in solvent-free LC electrolyte systems is achieved at high temperatures, that is, 150 8C and above. Recently we have shown that transition-metal aqua complex salts ([M ACHTUNGTRENNUNG(H2O)6]X2; in which M is a transition-metal cation and X is a suitable counterion), which have melting points close to room temperature, can also be used as solvents in the self-assembly process of some surfactants. The LLC mesophases of molten transition-metal-salt aqua complexes have important physical properties, such as high thermal stability (between 83 and 383 K), high ionic conductivity (room-temperature conductivities close to 2.0 10 4 Scm ), and nonvolatility. A highly concentrated aqueous electrolyte solution of an alkali metal salt can also act as a solvent in the assembly process of oligo(ethylene oxide) type surfactants, in which the highly concentrated electrolyte solution can be considered as an analogue of a molten salt. Their similarities arise due to strong ion–dipole (salt–water) interactions at high salt concentrations (highly concentrated refers to water/salt mole ratios of less than 8 in the case of lithium salts) and as a consequence, the heat of vaporization of water sharply increases. In this contribution, we have investigated the phase behavior and ionic conductivity of a new class of hydrated-salt/ surfactant mesophase, namely; LiNO3–H2O–C12EO10, LiCl– H2O–C12EO10, and LiClO4–H2O–C12EO10 systems, in which C12EO10 is C12H25 ACHTUNGTRENNUNG(OCH2CH2)10OH. The mesophase is a collaborative assembly of a hydrated salt species in the liquid phase and surfactant molecules. Earlier studies on salt– water–surfactant mesophases focus on the effect of salts on the phase behavior of surfactants in dilute aqueous solutions (18–1, water/salt mole ratio). Here, we demonstrate that as little as two water molecules per molecule of lithium salt is sufficient to form a LLC mesophase. At such a low water and high salt concentrations, the bulk properties of water are altered by the salt–water interactions and the salt– water couple collaboratively acts as the solvent in the LLC mesophase. An important outcome of the salt–water interaction is that the LLC mesophase is stable under ambient atmospheric conditions for years (see Supporting Information) and displays high ionic conductivity over a broad temperature range. The LLC samples were prepared by adding each ingredient: salt (LiNO3, LiCl, or LiClO4), surfactant (C12EO10), and water in the required amounts and the resulting mixture was then homogenized by constant shaking in a shaking water bath at 60–110 8C for 24 h. Under ambient conditions, the amount of water in the samples depends on the temperature, relative humidity, and the amount of salt in the mesophase, but always enough water remains in the samples to [a] C. Albayrak, Prof. . Dag Department of Chemistry, Bilkent University 06800, Ankara (Turkey) Fax: (+90)312-266-4068 E-mail : dag@fen.bilkent.edu.tr [b] Prof. A. Cihaner Department of Chemical Engineering and Applied Chemistry Atilim University 06836, Ankara (Turkey) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201103705.

The effects of diet and hindgut defaunation (removal of protozoa from the hindgut) on diet digestibility (Trial 1) and on total and cellulolytic bacterial and fungal concentrations in the cecum and colon (Trial 2) were investigated. A high-forage (HF) diet, 90% alfalfa hay-10% concentrate, or a higher-concentrate (HC) diet, 60% alfalfa hay-40% concentrate, was limit-fed. In Trial 1, defaunation resulted in a slight decrease in DM digestibility (P < .1) and had no effect on cellulose digestibility. Dry matter digestibility was higher (P < .001) with the HC diet; however, no differences were observed in cellulose digestion. For the faunated periods, protozoal concentrations were similar in the cecum and greater in the colon for both diets (P < .05). A diet x location interaction was observed for the genera Buetschlia and Blepharocorys. In Trial 2, defaunation had no effect on either total or cellulolytic bacterial concentrations in the cecum or colon. Total bacterial concentrations were higher (P < .06) in the colon when ponies were fed the HC diet. Defaunation did not affect total fungal concentrations in the cecum; however, fungal concentrations in the colon were slightly higher (P < .1) when the ponies were defaunated. Diet had no effect on total or cellulolytic fungal concentrations. Both total and cellulolytic fungal concentrations were approximately 10-fold higher in the colon than in the cecum (P < .01). Protozoa do not seem to play an essential role in the fermentation of feedstuffs in the equine hindgut.

Nest-Site Selection of American Oystercatchers (Haematopus palliatus) in Salt Marshes

The accompanying map shows the results of an airborne radioactivity survey along the Atlantic Ocean beach between Edisto Island, South Carolina and Cape Fear, North Carolina. The survey was made May 20, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude, parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the nominal 500 foot flight altitude varies with areal extent and intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1400 feet. The accompanying maps show the approximate locations of the areas of greater-than-average radioactivity (at left) and the location of the traverse flown (at right). The abnormal radioactivity is apparently caused by radioactive minerals associated with "black sand" deposits which occur locally along the beach in this region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given in the accompanying map showing the localities of greater-than-average radioactivity therefore, suggests areas in which uranium and thorium deposits are more likely to occur.