Exertional Heat Illness in American Football Players: When Is the Risk Greatest?

CONTEXT

Knowledge about the specific environmental and practice risks to participants in American intercollegiate football during preseason practices is limited. Identifying risks may mitigate occurrences of exertional heat illness (EHI).

OBJECTIVE

To evaluate the associations among preseason practice day, session number, and wet bulb globe temperature (WBGT) and the incidence of EHI.

DESIGN

Descriptive epidemiology study.

SETTING

Sixty colleges and universities representing 5 geographic regions of the United States.

PATIENTS OR OTHER PARTICIPANTS

National Collegiate Athletic Association football players.

MAIN OUTCOME MEASURE(S)

Data related to preseason practice day, session number, and WBGT. We measured WBGT every 15 minutes during the practice sessions and used the mean WBGT from each session in the analysis. We recorded the incidence of EHIs and calculated the athlete-exposures (AEs).

RESULTS

A total of 553 EHI cases and 365 810 AEs were reported for an overall EHI rate of 1.52/1000 AEs (95% confidence interval [CI] = 1.42, 1.68). Approximately 74% (n = 407) of the reported EHI cases were exertional heat cramps (incidence rate = 1.14/1000 AEs; 95% CI = 1.03, 1.25), and about 26% (n = 146) were a combination of exertional heat syncope and heat exhaustion (incidence rate = 0.40/1000 AEs; 95% CI = 0.35, 0.48). The highest rate of EHI occurred during the first 14 days of the preseason period, and the greatest risk was during the first 7 days. The risk of EHI increased substantially when the WBGT was 82.0°F (27.8°C) or greater.

CONCLUSIONS

We found an increased rate of EHI during the first 14 days of practice, especially during the first 7 days. When the WBGT was greater than 82.0°F (27.8°C), the rate of EHI increased. Sports medicine personnel should take all necessary preventive measures to reduce the EHI risk during the first 14 days of practice and when the environmental conditions are greater than 82.0°F (27.8°C) WBGT.

Culex pipiens and Stegomyia albopicta (= Aedes albopictus) populations as vectors for lineage 1 and 2 West Nile virus in Europe

The emerging disease West Nile fever is caused by West Nile virus (WNV), one of the most widespread arboviruses. This study represents the first test of the vectorial competence of European Culex pipiens Linnaeus 1758 and Stegomyia albopicta (= Aedes albopictus) (both: Diptera: Culicidae) populations for lineage 1 and 2 WNV isolated in Europe. Culex pipiens and S. albopicta populations were susceptible to WNV infection, had disseminated infection, and were capable of transmitting both WNV lineages. This is the first WNV competence assay to maintain mosquito specimens under environmental conditions mimicking the field (day/night) conditions associated with the period of maximum expected WNV activity. The importance of environmental conditions is discussed and the issue of how previous experiments conducted in fixed high temperatures may have overestimated WNV vector competence results with respect to natural environmental conditions is analysed. The information presented should be useful to policymakers and public health authorities for establishing effective WNV surveillance and vector control programmes. This would improve preparedness to prevent future outbreaks.

Evolutionary ecology of pipefish brooding structures: embryo survival and growth do not improve with a pouch

For animals that reproduce in water, many adaptations in life‐history traits such as egg size, parental care, and behaviors that relate to embryo oxygenation are still poorly understood. In pipefishes, seahorses and seadragons, males care for the embryos either in some sort of brood pouch, or attached ventrally to the skin on their belly or tail. Typically, egg size is larger in the brood pouch group and it has been suggested that oxygen supplied via the pouch buffers the developing embryos against hypoxia and as such is an adaptation that has facilitated the evolution of larger eggs. Here, using four pipefish species, we tested whether the presence or absence of brood pouch relates to how male behavior, embryo size, and survival are affected by hypoxia, with normoxia as control. Two of our studied species Entelurus aequoreus and Nerophis ophidion (both having small eggs) have simple ventral attachment of eggs onto the male trunk, and the other two, Syngnathus typhle (large eggs) and S. rostellatus (small eggs), have fully enclosed brood pouches on the tail. Under hypoxia, all species showed lower embryo survival, while species with brood pouches suffered greater embryo mortality compared to pouchless species, irrespective of oxygen treatment. Behaviorally, species without pouches spent more time closer to the surface, possibly to improve oxygenation. Overall, we found no significant benefits of brood pouches in terms of embryo survival and size under hypoxia. Instead, our results suggest negative effects of large egg size, despite the protection of brood pouches.

Oxidative Stress in Early Life: Associations with Sex, Rearing Conditions, and Parental Physiological Traits in Nestling Pied Flycatchers

Conditions experienced during juvenile development can affect the fitness of an organism. During early life, oxidative stress levels can be particularly high as a result of the increased metabolism and the relatively immature antioxidant system of the individual, and this may have medium- and long-term fitness consequences. Here we explore variation in levels of oxidative stress measured during early life in relation to sex, rearing conditions (hatching date and brood size), and parental condition and levels of oxidative markers in a wild population of the pied flycatcher (Ficedula hypoleuca) followed for 2 yr. A marker of total antioxidant status (TAS) in plasma and total levels of glutathione (GSH) in red blood cells, as well as a marker of oxidative damage in plasma lipids (malondialdehyde [MDA]), were assessed simultaneously. Our results show that nestling total GSH levels were associated with parental oxidative status, correlating negatively with maternal MDA and positively with total GSH levels of both parents, with a high estimated heritability. This suggests that parental physiology and genes could be determinants for endogenous components of the antioxidant system of the offspring. Moreover, we found that total GSH levels were higher in female than in male nestlings and that hatching date was positively associated with antioxidant defenses (higher TAS and total GSH levels). These results suggest that different components of oxidative balance are related to a variety of environmental and intrinsic--including parental--influencing factors. Future experimental studies must disentangle the relative contribution of each of these on nestling oxidative status and how the resulting oxidative stress at early phases shape adult phenotype and fitness.

Quantifying external focus of attention in sailing by means of action sport cameras

The aim of the current study was twofold: (1) to validate the use of action sport cameras for quantifying focus of visual attention in sailing and (2) to apply this method to examine whether an external focus of attention is associated with better performance in upwind sailing. To test the validity of this novel quantification method, we first calculated the agreement between gaze location measures and head orientation measures in 13 sailors sailing upwind during training regattas using a head mounted eye tracker. The results confirmed that for measuring visual focus of attention in upwind sailing, the agreement for the two measures was high (intraclass correlation coefficient (ICC) = 0.97) and the 95% limits of agreement were acceptable (between -8.0% and 14.6%). In a next step, we quantified the focus of visual attention in sailing upwind as fast as possible by means of an action sport camera. We captured sailing performance, operationalised as boat speed in the direction of the wind, and environmental conditions using a GPS, compass and wind meter. Four trials, each lasting 1 min, were analysed for 15 sailors each, resulting in a total of 30 upwind speed trials on port tack and 30 upwind speed trials on starboard tack. The results revealed that in sailing - within constantly changing environments - the focus of attention is not a significant predictor for better upwind sailing performances. This implicates that neither external nor internal foci of attention was per se correlated with better performances. Rather, relatively large interindividual differences seem to indicate that different visual attention strategies can lead to similar performance outcomes.

Vitamin E Content and Composition in Tomato Fruits: Beneficial Roles and Bio-Fortification

Several epidemiological studies have demonstrated that high vitamin E intakes are related to a reduced risk of non-communicable diseases, while other dietary antioxidants are not, suggesting that vitamin E exerts specific healthy functions in addition to its antioxidant role. In this regard, tomato (Solanum lycopersicum), one of the most consumed vegetables of the whole world population, is an important source of both tocopherols and tocotrienols. However, vitamin E content may strongly depend on several biotic and abiotic factors. In this review we will debate the elements affecting the synthesis of tocopherols and tocotrienols in tomato fruit, such as environmental conditions, genotype, fruit maturity level, and the impact of classical processing methods, such as pasteurization and lyophilization on the amount of these compounds. In addition we will analyze the specific vitamin E mechanisms of action in humans and the consequent functional effects derived from its dietary intake. Finally, we will examine the currently available molecular techniques used to increase the content of vitamin E in tomato fruit, starting from the identification of genetic determinants and quantitative trait loci that control the accumulation of these metabolites.

Sorption and desorption of Cr(VI) ions from water by biochars in different environmental conditions

In the present research, the potential of two biochars produced by the thermal decomposition of wheat straw (BCS) and wicker (BCW) for Cr(VI) ions removing from wastewater was investigated. The pH and the presence of chlorides and nitrates were also investigated. The Freundlich and Langmuir models were applied for the characterization of adsorption isotherms. The Langmuir model has better fitting of adsorption isotherms than the Freundlich model. The sorption process can be described by the pseudo second-order equation. The optimal adsorption capacities were obtained at pH 2 and were 24.6 and 23.6 mg/g for BCS and BCW, respectively. X-ray photoelectron spectroscopy (XPS) studies confirmed that Cr(III) ions were the most abundant chromium species on the biochars' surface. The results indicated that the sorption mechanism of Cr(VI) on biochar involves anionic and cationic adsorption combined with Cr(VI) species reduction.

Ecophysiological response to seasonal variations in water availability in the arborescent, endemic plant Vellozia gigantea

The physiological response of plants growing in their natural habitat is strongly determined by seasonal variations in environmental conditions and the interaction of abiotic and biotic stresses. Here, leaf water and nutrient contents, changes in cellular redox state and endogenous levels of stress-related phytohormones (abscisic acid (ABA), salicylic acid and jasmonates) were examined during the rainy and dry season in Vellozia gigantea, an endemic species growing at high elevations in the rupestrian fields of the Espinhaço Range in Brazil. Enhanced stomatal closure and increased ABA levels during the dry season were associated with an efficient control of leaf water content. Moreover, reductions in 12-oxo-phytodienoic acid (OPDA) levels during the dry season were observed, while levels of other jasmonates, such as jasmonic acid and jasmonoyl-isoleucine, were not affected. Changes in ABA and OPDA levels correlated with endogenous concentrations of iron and silicon, hydrogen peroxide, and vitamin E, thus indicating complex interactions between water and nutrient contents, changes in cellular redox state and endogenous hormone concentrations. Results also suggested crosstalk between activation of mechanisms for drought stress tolerance (as mediated by ABA) and biotic stress resistance (mediated by jasmonates), in which vitamin E levels may serve as a control point. It is concluded that, aside from a tight ABA-associated regulation of stomatal closure during the dry season, crosstalk between activation of abiotic and biotic defences, and nutrient accumulation in leaves may be important modulators of plant stress responses in plants growing in their natural habitat.

Weather variability influences color and phenolic content of pigmented baby leaf lettuces throughout the season

The lack of consistency in homogeneous color throughout the season of pigmented baby leaf lettuce is a problem for growers because of the rejection of the product and consequently the economic loss. Changes in color as well as individual and total phenolic composition and content as a response to the climatic variables were studied following the analysis of three pigmented baby leaf lettuces over 16 consecutive weeks from February to May, which corresponded to the most important production season in winter in Europe. Color and phenolic content were significantly (P ≤ 0.001) affected by cultivar, harvest week, and climatic variables that occurred in the last week before harvest. Radiation and temperature showed positive correlations with the content of phenolic acids and flavonoids that increased in all three cultivars as the season progressed. Cyanidin-3-O-(6''-O-malonyl)-glucoside content showed positive correlations with temperature and radiation but only in Batavia cultivars whereas in red oak leaf the correlation was with cold temperatures. Regarding hue angle, a positive correlation was shown with the number of hours at temperatures lower than 7 °C. A relationship between hue angle and the content of anthocyanins was not possible to establish. These results suggest that the colorimetric measurement of color cannot be used as a good indicator of anthocyanin accumulation because other pigments such as chlorophylls and carotenoids may contribute as well to the leaf color of pigmented lettuce. This study provides information about the impact of genotype and environment interactions on the biosynthesis of phenolic compounds to explain the variability in the leaf color and product appearance.

Evaluation of Diesel Exhaust Continuous Monitors in Controlled Environmental Conditions

Diesel exhaust (DE) contains a variety of toxic air pollutants, including diesel particulate matter (DPM) and gaseous contaminants (e.g., carbon monoxide (CO)). DPM is dominated by fine (PM2.5) and ultrafine particles (UFP), and can be representatively determined by its thermal-optical refractory as elemental carbon (EC) or light-absorbing characteristics as black carbon (BC). The currently accepted reference method for sampling and analysis of occupational exposure to DPM is the National Institute for Occupational Safety and Health (NIOSH) Method 5040. However, this method cannot provide in-situ short-term measurements of DPM. Thus, real-time monitors are gaining attention to better examine DE exposures in occupational settings. However, real-time monitors are subject to changing environmental conditions. Field measurements have reported interferences in optical sensors and subsequent real-time readings, under conditions of high humidity and abrupt temperature changes. To begin dealing with these issues, we completed a controlled study to evaluate five real-time monitors: Airtec real-time DPM/EC Monitor, TSI SidePak Personal Aerosol Monitor AM510 (PM2.5), TSI Condensation Particle Counter 3007, microAeth AE51 BC Aethalometer, and Langan T15n CO Measurer. Tests were conducted under different temperatures (55, 70, and 80°F), relative humidity (10, 40, and 80%), and DPM concentrations (50 and 200 μg/m(3)) in a controlled exposure facility. The 2-hr averaged EC measurements from the Airtec instrument showed relatively good agreement with NIOSH Method 5040 (R(2) = 0.84; slope = 1.17±0.06; N = 27) and reported ∼17% higher EC concentrations than the NIOSH reference method. Temperature, relative humidity, and DPM levels did not significantly affect relative differences in 2-hr averaged EC concentrations obtained by the Airtec instrument vs. the NIOSH method (p < 0.05). Multiple linear regression analyses, based on 1-min averaged data, suggested combined effects of up to 5% from relative humidity and temperature on real-time measurements. The overall deviations of these real-time monitors from the NIOSH method results were ≤20%. However, simultaneous monitoring of temperature and relative humidity is recommended in field investigations to understand and correct for environmental impacts on real-time monitoring data.

Effect of culture conditions on the resistance of Pseudomonas aeruginosa biofilms to disinfecting agents

The relationship between the environmental conditions of biofilm formation and resistance to disinfectants was studied. Anti-biofilm assays were performed against biofilms grown at 20, 30 and 37°C on stainless steel and polycarbonate, over 24 and 48 h. A rise in growth temperature increased the resistance of 24 h biofilms to disinfectants containing didecyldimethylammonium chloride and decreased it to a disinfectant containing alkyldimethylbenzylammonium chloride. The increase in growth temperature coupled with an incubation time of 24 h promoted increases in both matrix production and the membrane rigidity of sessile cells. An increase in incubation time also increased both matrix production and the membrane rigidity of sessile cells. Such phenomena resulted in an increased resistance to disinfectants of biofilms grown at 20 and 30°C. The resistance of 48 h biofilms to disinfectants decreased with an increase in growth temperature despite the increase in matrix production and the membrane rigidity of sessile cells.

Differences in the antibacterial activity of nisin and bovicin HC5 against Salmonella Typhimurium under different temperature and pH conditions

AIMS

To compare the action of nisin and bovicin HC5 in combination with EDTA on Salmonella Typhimurium under different environmental conditions.

METHODS AND RESULTS

Salmonella Typhimurium was treated in BHI broth containing EDTA (1·5 mmol l(-1)) and nisin or bovicin HC5 (200 AU ml(-1)) under different pH and temperature conditions, and according to a central composite design with two factors (temperature and pH). Cell viability was evaluated on plate count agar for 48 h. The combination of nisin or bovicin HC5 with EDTA was able to inhibit the growth of Salmonella, but the temperature and pH conditions promoting inhibition were distinct for each bacteriocin. Nisin was bactericidal over a broad range of temperature and pH, while bovicin HC5 was bacteriostatic in most conditions and bactericidal only in specific conditions (pH >6·0 and temperature >30°C). Salmonella Typhimurium did not show tolerance to bovicin HC5 or cross-tolerance between these lantibiotics.

CONCLUSIONS

Nisin and bovicin HC5 both inhibited the growth of Salmonella, but the activity of each bacteriocin was differently influenced by environmental conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Nisin and bovicin HC5 have the potential to inhibit the growth of Salmonella, but environmental conditions should be considered to establish optimal conditions for its application.

Optimization of culture conditions of Fusarium solani for the production of neoN-methylsansalvamide

The aim of this study was to optimize the culture conditions of Fusarium solani KCCM90040 on cereal grain for the production of neoN-methylsansalvamide, a novel low-molecular-weight cyclic pentadepsipeptide exhibiting cytotoxic and multidrug resistance reversal effects. From the analysis of variance results using response surface methodology, temperature, initial moisture content, and growth time were shown to be important parameters for the production of neoN-methylsansalvamide on cereal grain. A model was established in the present study to describe the relationship between environmental conditions and the production of neoN-methylsansalvamide on rice, the selected cereal grain. The optimal culture conditions were determined at 25.79 °C with the initial moisture content of 40.79%, and 16.19 days of growth time. This report will give important information concerning the optimization of environmental conditions using statistic methodology for the production of a new cyclic pentadepsipeptide from fungi.

Birth of common shovelnose rays (Glaucostegus typus) under captive conditions

The common shovelnose ray (Glaucostegus typus) is a poorly studied species of the Rhinobatidae family that occurs throughout the Indo-West Pacific. Although common in aquariums throughout the United States, there are currently no records of captive birth events. In 2013, a female common shovelnose ray housed at the Downtown Aquarium in Houston, Texas, USA gave birth to eleven pups. Although all pups were stillborn, this event demonstrates that it is possible to breed common shovelnose rays in a controlled environment. The single female and two male common shovelnose rays at the aquarium are of sexually mature size (between 206 and 240 cm total length, TL), demonstrate mating behaviors, and provide an excellent opportunity to investigate the reproductive biology of this species. Captive environmental conditions of the birth enclosure may be useful in replicating the birthing event in order to develop a breeding program that could potentially relieve collection pressures on wild populations of guitarfish given their vulnerable status.

Diarrhea incidence and intestinal infections among rotavirus vaccinated infants from a poor area in Brazil: a spatial analysis

BACKGROUND

Acute diarrhea is the second leading cause of mortality among children under 5 years of age in developing countries. The pathogen most strongly associated with diarrhea is rotavirus followed by enteric pathogens such as bacteria, helminthes and protozoan. Adequate sanitation and water supply contribute to decrease acute diarrhea incidence of most etiologic agents, although vaccination remains the most important intervention to control rotavirus acute diarrhea. This study aimed to describe environmental conditions and analyze spatially the acute diarrhea and intestinal infection among rotavirus vaccinated infants from Laranjeiras-Sergipe, Brazil.

METHODS

Children were enrolled between 2 and 11 months of age and followed through 12 months. Demographic, socioeconomic and environmental data were obtained from a questionnaire, and immunization data were obtained from children vaccination card. Children stool samples were collected each month in order to run laboratory analyses. The household spatial localization was obtained by using a Global Positioning System (GPS). Spatial analysis was performed using the TerraView computer program and Kernel intensity estimation.

RESULTS

A total of 1,113 stool samples were collected with 80 being diarrhea associated. Diarrhea incidence rate was 0.5 ± 1.0 episodes/child/year. The overall infection rates by Ascaris lumbricoides, Endolimax nana, Giardia lamblia and rotavirus were 5.1%, 3.0%, 0.9% and 2.6%, respectively. 3.8% of diarrhea-associated stool samples were positive for rotavirus and 11.3% were positive for helminths and protozoans. There were some changes on spatial distribution of intestinal infections and diarrhea episodes along the four trimesters evaluated.

CONCLUSIONS

The studied infants live equally in precarious conditions of sanitation which probably explain the significant rates of parasitic infections appearing in early life. The low acute diarrhea incidence in the studied rotavirus vaccinated population and the low number of symptomatic rotavirus infection may indicate vaccination efficacy to prevent acute diarrhea among young children in a poor environmental sanitary setting.

Affluence and objective environmental conditions: Evidence of differences in environmental concern in metropolitan Brazil

In an age of climate change, researchers need to form a deepened understanding of the determinants of environmental concern, particularly in countries of emerging economies. This paper provides a region-specific investigation of the impact of socio-economic status (SES) and objective environmental conditions on environmental concern in urban Brazil. We make use of data that were collected from personal interviews of individuals living in the metropolitan areas of Baixada Santista and Campinas, in the larger São Paulo area. Results from multilevel regression models indicate that wealthier households are more environmentally concerned, as suggested by affluence and post-materialist hypotheses. However, we also observe that increasing environmental concern correlates with a decline in objective environmental conditions. Interactions between objective environmental conditions and SES reveal some intriguing relationships: Among poorer individuals, a decline in environmental conditions increases environmental concern as suggested by the objective problems hypothesis, while for the wealthy, a decline in environmental conditions is associated with lower levels of environmental concern.

Dynamic Accuracy of GPS Receivers for Use in Health Research: A Novel Method to Assess GPS Accuracy in Real-World Settings

The emergence of portable global positioning system (GPS) receivers over the last 10 years has provided researchers with a means to objectively assess spatial position in free-living conditions. However, the use of GPS in free-living conditions is not without challenges and the aim of this study was to test the dynamic accuracy of a portable GPS device under real-world environmental conditions, for four modes of transport, and using three data collection intervals. We selected four routes on different bearings, passing through a variation of environmental conditions in the City of Copenhagen, Denmark, to test the dynamic accuracy of the Qstarz BT-Q1000XT GPS device. Each route consisted of a walk, bicycle, and vehicle lane in each direction. The actual width of each walking, cycling, and vehicle lane was digitized as accurately as possible using ultra-high-resolution aerial photographs as background. For each trip, we calculated the percentage that actually fell within the lane polygon, and within the 2.5, 5, and 10 m buffers respectively, as well as the mean and median error in meters. Our results showed that 49.6% of all ≈68,000 GPS points fell within 2.5 m of the expected location, 78.7% fell within 10 m and the median error was 2.9 m. The median error during walking trips was 3.9, 2.0 m for bicycle trips, 1.5 m for bus, and 0.5 m for car. The different area types showed considerable variation in the median error: 0.7 m in open areas, 2.6 m in half-open areas, and 5.2 m in urban canyons. The dynamic spatial accuracy of the tested device is not perfect, but we feel that it is within acceptable limits for larger population studies. Longer recording periods, for a larger population are likely to reduce the potentially negative effects of measurement inaccuracy. Furthermore, special care should be taken when the environment in which the study takes place could compromise the GPS signal.

The effect and role of environmental conditions on magnetosome synthesis

Magnetotactic bacteria (MTB) are considered the model species for the controlled biomineralization of magnetic Fe oxide (magnetite, Fe3O4) or Fe sulfide (greigite, Fe3S4) nanocrystals in living organisms. In MTB, magnetic minerals form as membrane-bound, single-magnetic domain crystals known as magnetosomes and the synthesis of magnetosomes by MTB is a highly controlled process at the genetic level. Magnetosome crystals reveal highest purity and highest quality magnetic properties and are therefore increasingly sought after as novel nanoparticulate biomaterials for industrial and medical applications. In addition, "magnetofossils," have been used as both past terrestrial and potential Martian life biosignature. However, until recently, the general belief was that the morphology of mature magnetite crystals formed by MTB was largely unaffected by environmental conditions. Here we review a series of studies that showed how changes in environmental factors such as temperature, pH, external Fe concentration, external magnetic fields, static or dynamic fluid conditions, and nutrient availability or concentrations can all affect the biomineralization of magnetite magnetosomes in MTB. The resulting variations in magnetic nanocrystals characteristics can have consequence both for their commercial value but also for their use as indicators for ancient life. In this paper we will review the recent findings regarding the influence of variable chemical and physical environmental control factors on the synthesis of magnetosome by MTB, and address the role of MTB in the global biogeochemical cycling of iron.

Extensive transcript diversity and novel upstream open reading frame regulation in yeast

To understand the diversity of transcripts in yeast (Saccharomyces cerevisiae) we analyzed the transcriptional landscapes for cells grown under 18 different environmental conditions. Each sample was analyzed using RNA-sequencing, and a total of 670,446,084 uniquely mapped reads and 377,263 poly-adenylated end tags were produced. Consistent with previous studies, we find that the majority of yeast genes are expressed under one or more different conditions. By directly comparing the 5′ and 3′ ends of the transcribed regions, we find extensive differences in transcript ends across many conditions, especially those of stationary phase, growth in grape juice, and salt stimulation, suggesting differential choice of transcription start and stop sites is pervasive in yeast. Relative to the exponential growth condition (i.e., YPAD), transcripts differing at the 5′ ends and 3′ ends are predicted to differ in their annotated start codon in 21 genes and their annotated stop codon in 63 genes. Many (431) upstream open reading frames (uORFs) are found in alternate 5′ ends and are significantly enriched in transcripts produced during the salt response. Mutational analysis of five genes with uORFs revealed that two sets of uORFs increase the expression of a reporter construct, indicating a role in activation which had not been reported previously, whereas two other uORFs decreased expression. In addition, RNA binding protein motifs are statistically enriched for alternate ends under many conditions. Overall, these results demonstrate enormous diversity of transcript ends, and that this heterogeneity is regulated under different environmental conditions. Moreover, transcript end diversity has important biological implications for the regulation of gene expression. In addition, our data also serve as a valuable resource for the scientific community.

Environmental conditions, political economy, and rates of injection drug use in large US metropolitan areas 1992-2002

City-specific studies have suggested the quality of the local environment and economic circumstances are associated with greater risk of injection drug use (IDU). No studies have assessed the relation among the quality of the local environment, economic circumstances, and IDU over time across US metropolitan areas. Annual numbers of IDUs in the 88 largest US metropolitan statistical areas (MSAs) were estimated by extrapolating, adjusting, and allocating existing estimates using various data sources. Generalized estimating equations were used to assess the relation among the quality of the local environment, metropolitan political economy, and IDU prevalence using lagged models taking into account potential confounders. MSAs with a worse local environment (measured as a one standard deviation difference) had a greater risk of IDU (relative risk [RR]=1.03, 95% confidence interval [CI]: 1.01, 1.06); similarly, a one-percentage point worsening of the political economy for an MSA was associated with greater risk of IDU (RR=1.04-1.10). Final models stratified by region indicated heterogeneity of effect by region whereby the quality of the local environment was associated with IDU strongest in the South (RR=1.12, CI: 1.05, 1.12) followed by the West (RR=1.04, CI: 1.01, 1.07) and Midwest (RR=1.03, CI: 1.00, 1.06), and the metropolitan political economy was associated with IDU in the West (RR=1.03-1.09) and Northeast (RR=1.04-1.12). Our results underscore the importance of sociopolitical factors as determinants of IDU in MSAs. Structural solutions targeted at improving environmental conditions and economic circumstances should be considered as drug use interventions.

Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

The effects of temperature on real time changes in optical density (DeltaOD) of GAFCHROMIC EBT film were investigated. The spectral peak of maximum change in absorbance (lambdamax) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 degrees C. The DeltaOD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in lambdamax. A compensation scheme using lambdamax and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry.

Uncoupled geographical variation between leaves and flowers in a South-Andean Proteaceae

BACKGROUND AND AIMS

Geographical variation in foliar and floral traits and their degree of coupling can provide relevant information on the relative importance of abiotic, biotic and even neutral factors acting at geographical scales as generators of evolutionary novelty. Geographical variation was studied in leaves and flowers of Embothrium coccineum, a species that grows along abrupt environmental gradients and exhibits contrasting pollinator assemblages in the southern Andes.

METHODS

Five foliar and eight floral morphological characters were considered from 32 populations, and their patterns of variation and covariation were analysed within and among populations, together with their relationship with environmental variables, using both univariate and multivariate methods. The relationships between foliar and floral morphological variation and geographical distance between populations were compared with Mantel permutation tests.

KEY RESULTS

Leaf and flower traits were clearly uncoupled within populations and weakly associated among populations. Whereas geographical variation in foliar traits was mostly related to differences in precipitation associated with geographical longitude, variation in floral traits was not.

CONCLUSIONS

These patterns suggest that leaves and flowers responded to different evolutionary forces, environmental (i.e. rainfall) in the case of leaves, and biotic (i.e. pollinators) or genetic drift in the case of flowers. This study supports the view that character divergence at a geographical scale can be moulded by different factors acting in an independent fashion.

A cellular hypothesis for the induction of blossom-end rot in tomato fruit

BACKGROUND

The incidence of blossom-end rot (BER) is generally associated with a calcium (Ca) deficiency in the distal portion of tomato fruits. The visible symptom is a necrotic lesion, which is presumed to be a consequence of cell death and the subsequent leakage of solutes into the extracellular space. Environmental factors that affect either fruit cell expansion or Ca delivery to the distal portion of the fruit influence the occurrence of BER. However, since no absolute, critical fruit Ca concentration for the occurrence of BER has been identified, it is now important to define the role of Ca in fruit cell physiology and to seek the cause of BER at the cellular level.

HYPOTHESIS

Here, it is suggested that BER is initiated by a cellular dysfunction in the distal portion of a young fruit during rapid cell expansion. It is proposed that insufficient Ca(2+) is available for critical apoplastic and cytoplasmic functions when the cellular Ca demand imposed by vacuolation exceeds the Ca delivery to an expanding cell. A local Ca deficiency, therefore, may result in aberrant intracellular Ca(2+) signals, a weakening of cell walls and a loss of cellular integrity. Ultimately it may lead to cell death and the visible symptoms of BER. Several experimental strategies are suggested to confirm the occurrence of aberrant Ca(2+) concentrations in cells contributing to BER.

PERSPECTIVE

Many genetic and genomic resources are becoming available for tomato. Ultimately, these will allow genes affecting the occurrence of BER to be identified. Such knowledge will inform breeding strategies to eliminate BER. In the meanwhile, increasing the apoplastic Ca concentration in susceptible fruit tissue should provide a simple and reliable, practical solution for the prevention of BER in tomatoes. It is suggested that current horticultural practices, such as the manipulation of the mineral composition of the feed or the growth environment, are not completely effective in reducing BER because they affect apoplastic Ca concentration in fruit tissue indirectly. Therefore, spraying Ca directly onto young fruits is recommended for the prevention of BER.

Sex change towards female in dying Acer rufinerve trees

BACKGROUND AND AIMS

Sex changes within the genus Acer (Aceraceae) may occur because of associations of sex expression and plant health. In this study, a natural population of Acer rufinerve was monitored to clarify the sex change patterns, the relationship between sex expression and plant health, and the causal environmental conditions that precede sex changes.

METHODS

Sex expression, growth rate and mortality of A. rufinerve trees in a natural population were monitored from 1992 to 1997.

KEY RESULTS

Three types of sex expression were observed among A. rufinerve: male, female and bisexual. Among the three types of sex expression, sex changes occurred in all directions. In the growing season of 1994, precipitation was reduced. Stem growth rate decreased and mortality was high in 1994. In the spring of 1995, a drastic sex change from male to female or to bisexual occurred. As a result, the sex ratio became female-biased in 1995, although it had been male-biased from 1992 to 1994. In 1996 and 1997, the proportion of males in the population increased, partly as a result of female mortality and partly as a result of female-to-male sex changes. Sex expression of A. rufinerve was associated with their growth rate and mortality. The growth rate decreased for trees whose sex changed from male to female or to bisexual, and increased for trees whose sex changed from female to male or to bisexual. Dead trees reproduced as females before they died, except for those that died as males in 1994.

CONCLUSIONS

One explanation for the sex change towards increasing femaleness for this A. rufinerve population in 1995 was the deterioration of plant health in the previous growing season, because of reduced precipitation. Sex changes of unhealthy and dying A. rufinerve towards femaleness may facilitate re-occupancy by offspring in gaps created by the death of A. rufinerve trees.

Infection, Colonization, and Disease of Amaranthus hybridus Leaves by the Alternaria tenuissima Group

With the increased use of Amaranthus hybridus as a leafy-vegetable crop in Africa and the recent identification of Alternaria leaf spot on this host in southern Africa, the role of this potentially damaging pathogen was investigated. The goals of this study were to test the pathogenicity of the Alternaria tenuissima group, determine how these fungi infect Amaranthus hybridus leaves, and examine the colonization pattern within host tissues. Asymptomatic leaves of Amaranthus hybridus were collected from two field sites in South Africa. Eight A. tenuissima group isolates collected from these leaves were used in inoculation experiments conducted in both greenhouse and growth chamber studies. Scanning electron microscopy revealed A. tenuissima-like conidia germinating on leaf surfaces and mycelia entering leaves only through stomata of both field-collected and artificially inoculated leaves. Unwounded, inoculated leaves had no symptoms, and light-microscopy observations of both asymptomatic field-collected and unwounded and inoculated leaves revealed hyphae in mesophyll tissue growing intercellularly with no host cell penetration or host-cell response. Seven of the eight isolates produced brown to black, circular to oval, necrotic lesions only at the wound site of injured and inoculated leaves. These results confirm that isolates of the A. tenuissima group can infect and colonize Amaranthus hybridus leaves in a manner consistent with other endophytic fungi, and suggest that these fungi can act as latent leaf pathogens when the host is altered by wounding.