Crop pollination exposes honey bees to pesticides which alters their susceptibility to the gut pathogen Nosema ceranae

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

Development of a lipopeptide-based therapeutic vaccine to treat chronic HBV infection. I. Induction of a primary cytotoxic T lymphocyte response in humans

Our goal is to use peptide epitopes that are recognized by cytotoxic T lymphocytes (CTL) as immunogens for the development of prophylactic and therapeutic vaccines with chronic hepatitis B virus (HBV) infection being our first therapeutic target. Because most CTL peptide epitopes are poor immunogens, we specifically modified them by covalently attaching two additional components: a T helper peptide epitope and two lipid molecules. Using the murine influenza virus CTL epitope NP 147-155 as a model system, we found this construct to be highly immunogenic, and a single injection resulted in memory CTL induction that persisted for > 1 yr. Based on the animal studies, a vaccine was designed and tested for both safety and its ability to induce a primary CTL response in normal subjects. The three vaccine components included HBV core antigen peptide 18-27 as the CTL epitope, tetanus toxoid peptide 830-843 as the T helper peptide, and two palmitic acid molecules as the lipids. A dose escalation trial (5, 50, and 500 micrograms) carried out in 26 normal subjects showed that the vaccine was safe and able to induce a primary HBV-specific CTL response. A dose-response curve was observed and five out of five subjects responded to the 500-micrograms dose.

Quantification of fructans, galacto-oligosacharides and other short-chain carbohydrates in processed grains and cereals

BACKGROUND

Wholegrain grains and cereals contain a wide range of potentially protective factors that are relevant to gastrointestinal health. The prebiotics best studied are fructans [fructooligosaccharides (FOS), inulin] and galactooligosaccharides (GOS). These and other short-chain carbohydrates can also be poorly absorbed in the small intestine (named fermentable oligo-, di- and monosaccharides and polyols; FODMAPs) and may have important implications for the health of the gut.

METHODS

In the present study, FODMAPs, including fructose in excess of glucose, FOS (nystose, kestose), GOS (raffinose, stachyose) and sugar polyols (sorbitol, mannitol), were quantified using high-performance liquid chromatography with an evaporative light scattering detector. Total fructan was quantified using an enzymic hydrolysis method.

RESULTS

Fifty-five commonly consumed grains, breakfast cereals, breads, pulses and biscuits were analysed. Total fructan were the most common short-chain carbohydrate present in cereal grain products and ranged (g per portion as eaten) from 1.12 g in couscous to 0 g in rice; 0.6 g in dark rye bread to 0.07 g in spelt bread; 0.96 g in wheat-free muesli to 0.11 g in oats; and 0.81 g in muesli fruit bar to 0.05 g in potato chips. Raffinose and stachyose were most common in pulses.

CONCLUSIONS

  Composition tables including FODMAPs and prebiotics (FOS and GOS) that are naturally present in food will greatly assist research aimed at understanding their physiological role in the gut.

Structural and mechanistic insights into the interaction between Rho and mammalian Dia

Formins are involved in a variety of cellular processes that require the remodelling of the cytoskeleton. They contain formin homology domains FH1 and FH2, which initiate actin assembly. The Diaphanous-related formins form a subgroup that is characterized by an amino-terminal Rho GTPase-binding domain (GBD) and an FH3 domain, which bind somehow to the carboxy-terminal Diaphanous autoregulatory domain (DAD) to keep the protein in an inactive conformation. Upon binding of activated Rho proteins, the DAD is released and the ability of the formin to nucleate and elongate unbranched actin filaments is induced. Here we present the crystal structure of RhoC in complex with the regulatory N terminus of mammalian Diaphanous 1 (mDia1) containing the GBD/FH3 region, an all-helical structure with armadillo repeats. Rho uses its 'switch' regions for interacting with two subdomains of GBD/FH3. We show that the FH3 domain of mDia1 forms a stable dimer and we also identify the DAD-binding site. Although binding of Rho and DAD on the N-terminal fragment of mDia1 are mutually exclusive, their binding sites are only partially overlapping. On the basis of our results, we propose a structural model for the regulation of mDia1 by Rho and DAD.

Socioeconomic factors, perceived control and self-reported health in Russia. A cross-sectional survey

Russia has the lowest life expectancy among industrialised countries, but little is known about other health outcomes and determinants of health in the Russian population. Here we report a cross-sectional study in a national sample of the Russian population of social and psychosocial determinants of two self-reported health indicators: self-rated health (shown to predict mortality in prospective studies) and physical functioning (validated against more objective health measures). A multi-stage sample of the Russian population aged 18 years and more was interviewed (n=1599, response rate 66%). The questionnaire included political attitudes, social and economic circumstances, psychosocial factors, smoking, alcohol consumption, self-rated health and physical functioning (from the SF36 instrument). Scores of perceived control over life and over one's health were calculated from 6 and 3 questions, respectively. Data were analysed in logistic regression for two dichotomised outcomes: poor self-rated health (worse than average) and low physical functioning (less than 60% of maximum). Overall, 25% of subjects rated their health as worse than average; this is substantially more than in western countries. Perceived control over life was strongly related to both outcomes; age- and sex-adjusted OR for 1 standard deviation increase in control were 0.60 (95% CI 0.52-0.69) for poor self-rated health and 0.67 (0.57-0.81) for low physical functioning. Adjustment for a battery of other factors reduced these estimates only slightly. Associations between control over one's health and both outcomes were also significant, but weaker and attenuated in multivariate models. Material deprivation was also strongly related to both outcomes. Education was inversely related to self-rated health, and unmarried men reported poor physical functioning substantially more often. Subjects not approving the economic changes reported poorer health but this association was removed by adjustment for socioeconomic factors and control. Subjects who could not rely on informal social structures when in problems reported worse health; this effect largely persisted in multivariate analyses. These results are consistent with the hypothesis that poor health status in Russia is related to dysfunction of social structures, socioeconomic deprivation, and lack of perceived control. The absence of informal social networks, vital for maintaining general welfare, seems to affect adversely self-rated health. Deprivation and low perceived control may be important mediators between the broad social environment and health in populations undergoing transition and can provide a useful framework for many biological and behavioural factors. Prospective studies are needed to address the issue of temporality and reporting bias, the major problems in interpreting these findings.

Socioeconomic factors, material inequalities, and perceived control in self-rated health: cross-sectional data from seven post-communist countries

This study examined the association between perceived control and several socioeconomic variables and self-rated health in seven post-communist countries (Russia, Estonia, Lithuania, Latvia, Hungary, Poland, Czech Republic). Questionnaire interviews were used to collect data on self-rated health in the last 12 months, education, marital status, perceived control based on nine questions, and material deprivation based on availability of food, clothing and heating. For each population, two ecological measures of material inequalities were available: an inequality score estimated from the survey data as the distance between the 90th and 10th percentiles of material deprivation, and Gini coefficient from published sources. Data on 5330 men and women aged 20-60 were analysed. Prevalence of poor health (worse than average) varied between 8% in Czechs and 19% in Hungarians. The age-sex-adjusted odds ratio for university vs primary education was 0.36 (0.26-0.49); odds ratios per 1 standard deviation increase in perceived control and in material deprivation were 0.58 (95% CI 0.48-0.69) and 1.51 (1.40-1.63), respectively. The odds ratio for an increase in inequality equivalent to the difference between the most and the least unequal populations was 1.49 (0.88-2.52) using the material inequality score and 1.41 (0.91-2.20) using the Gini coefficient. No indication of an effect of either inequality measure was seen after adjustment for individuals' deprivation or perceived control. The results suggest that, as in western populations, education and material deprivation are strongly related to self-rated health. Perceived control appeared statistically to mediate some of the effects of material deprivation. The non-significant effects of both ecological measures of inequality were eliminated by controlling for individuals' characteristics.

How much does social capital add to individual health? A survey study of Russians

Some Russians are healthier than others. To what extent does their health vary with involvement or exclusion from social capital networks? The first section reviews alternative theories: human capital as the primary determinant; social capital, whether generic, situation-specific or simply a new label for old measures of social integration; or a composite theory--both human and social capital are major determinants of health. The evidence to test hypotheses consists of individual-level data about self-assessed physical and emotional health from the special-purpose social capital questionnaire used in the 1998 New Russia Barometer survey, a nationwide representative sample of the adult Russian population. Multiple regression analysis shows that on their own human capital and social capital each account for a notable amount of variance in health. When both forms of capital are combined in a composite model, each retains major influence, demonstrating that social capital does make an independent contribution to health. Significant social capital influences include involvement or exclusion from formal and informal networks; friends to rely on when ill; control over one's own life; and trust. Significant human capital influences besides age include subjective social status, gender and income. Regression-based estimates of impact show that social capital increases physical and emotional health more than human capital; together they can easily raise an individual's self-reported health from just below average on a five-point scale to approaching good health.

Helicobacter mustelae-associated gastritis in ferrets. An animal model of Helicobacter pylori gastritis in humans

Gastric Helicobacter mustelae was present in 100% of 11 adult female ferrets (Mustela putorius furo). The high immunoglobulin G antibody levels to H. mustelae in all ferrets showed a significant immune response to the organism. Urease mapping of the ferret stomach indicated that the bacteria heavily colonized the proximal duodenum and antrum and, to a lesser extent, the corpus. The histological gastritis observed coincided with presence of H. mustelae. Superficial gastritis was noted in the oxyntic gastric mucosa, whereas in the distal antrum the chronic inflammatory response occupied the full thickness of the mucosa. In the proximal antrum and transitional mucosa, focal glandular atrophy and regeneration were observed. Seven control specific-pathogen-free ferrets were not colonized with the bacteria, did not have detectable levels of immunoglobulin G H. mustelae antibody, and did not have H. mustelae-associated gastritis. The ferret lacks the polymorphonuclear-cell response seen in active chronic gastritis typically described with Helicobacter pylori gastritis in humans. However, the lesion in ferrets does closely resemble the diffuse antral gastritis seen in a subset of adults with H. pylori gastritis as well as children infected with H. pylori. Like H. pylori, H. mustelae adheres tightly to gastric mucosa. The ferret infected with H. mustelae, in addition to specific-pathogen-free uninfected control ferrets, will make longitudinal studies possible, enabling dissection of multiple host and environmental variables that influence the effect of H. mustelae colonization on progression and severity of gastroduodenal disease.

Efficacies of entecavir against lamivudine-resistant hepatitis B virus replication and recombinant polymerases in vitro

Entecavir (ETV) is a potent and selective inhibitor of hepatitis B virus (HBV) replication in vitro and in vivo that is currently in clinical trials for the treatment of chronic HBV infections. A major limitation of the current HBV antiviral therapy, lamivudine (3TC), is the emergence of drug-resistant HBV in a majority of treated patients due to specific mutations in the nucleotide binding site of HBV DNA polymerase (HBV Pol). To determine the effects of 3TC resistance mutations on inhibition by ETV triphosphate (ETV-TP), a series of in vitro studies were performed. The inhibition of wild-type and 3TC-resistant HBV Pol by ETV-TP was measured using recombinant HBV nucleocapsids, and compared to that of 3TC-TP. These enzyme inhibition studies demonstrated that ETV-TP is a highly potent inhibitor of wild-type HBV Pol and is 100- to 300-fold more potent than 3TC-TP against 3TC-resistant HBV Pol. Cell culture assays were used to gauge the potential for antiviral cross-resistance of 3TC-resistant mutants to ETV. Results demonstrated that ETV inhibited the replication of 3TC-resistant HBV, but 20- to 30-fold higher concentrations were required. To gain further perspective regarding the potential therapeutic use of ETV, its phosphorylation was examined in hepatoma cells treated with extracellular concentrations representative of drug levels in plasma in ETV-treated patients. At these concentrations, intracellular ETV-TP accumulated to levels expected to inhibit the enzyme activity of both wild-type and 3TC-resistant HBV Pol. These findings are predictive of potent antiviral activity of ETV against both wild-type and 3TC-resistant HBV.

Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies

Survival and growth of monarch larvae, Danaus plexippus (L.), after exposure to either Cry1Ab-expressing pollen from three Bacillus thuringiensis (Bt) corn (Zea mays L.) events differing in toxin expression or to the insecticide, lambda-cyhalothrin, were examined in field studies. First instars exposed to low doses ( approximately 22 grains per cm(2)) of event-176 pollen gained 18% less weight than those exposed to Bt11 or Mon810 pollen after a 5-day exposure period. Larvae exposed to 67 pollen grains per cm(2) on milkweed leaves from within an event-176 field exhibited 60% lower survivorship and 42% less weight gain compared with those exposed to leaves from outside the field. In contrast, Bt11 pollen had no effect on growth to adulthood or survival of first or third instars exposed for 5 days to approximately 55 and 97 pollen grains per cm(2), respectively. Similarly, no differences in larval survivorship were observed after a 4-day exposure period to leaves with 504-586 (within fields) or 18-22 (outside the field) pollen grains per cm(2) collected from Bt11 and non-Bt sweet-corn fields. However, survivorship and weight gain were drastically reduced in non-Bt fields treated with lambda-cyhalothrin. The effects of Bt11 and Mon810 pollen on the survivorship of larvae feeding 14 to 22 days on milkweeds in fields were negligible. Further studies should examine the lifetime and reproductive impact of Bt11 and Mon810 pollen on monarchs after long-term exposure to naturally deposited pollen.

The role of the left prefrontal cortex in verbal processing: semantic processing or willed action?

This study was designed to test the various proposed explanations (semantic processing, willed action, production of a spoken response) for the unilateral activation of the left prefrontal cortex noted in PET studies of verbal processing. Twenty subjects underwent 15O-water PET scans while undertaking a lexical task (detecting the letter 'a' in visually presented words) and a semantic task (categorizing nouns into living/non-living). The semantic task resulted in a significant unilateral left dorsolateral prefrontal activation. This finding suggests that the left inferior prefrontal cortex is the anatomical region involved in 'working with meaning', and that the activation does not reflect willed action, is not task-specific and is not attributable to the requirements of a spoken response.

Alcohol consumption in a national sample of the Russian population

AIMS

Alcohol has been suggested as an important determinant of mortality in Russia but survey data on individuals' alcohol consumption in Russia are sparse. We have analysed the levels and distribution of alcohol consumption in a national sample of the Russian population.

DESIGN

Cross-sectional survey.

PARTICIPANTS

A multi-stage random sample of men and women of the Russian Federation (N = 1599, response rate 66%).

MEASUREMENTS

Data on frequency of drinking alcohol and the average amount consumed at one occasion were collected in an interview. Information was also collected on smoking, self-rated health and a broad range of socio-economic factors and political attitudes.

FINDINGS

Nine per cent of men and 35% of women reported that they never drink alcohol; 10% of men and 2% women drink several times a week; 44% of men and 6% of women reported that they drink an equivalent of 25 cl of vodka or more at one occasion and 31% of men and 3% of women would do so at least once a month (25 cl of vodka contains 78.5 g of absolute alcohol). There were differences in alcohol consumption between geographical areas. Material deprivation was not related to alcohol consumption. Among men, smokers, unmarried, unemployed and men reporting poor health consumed more alcohol; women with higher education, widows, non-smoking and with worse health consumed less alcohol. Variables related to reaction to economic and political changes, rating of family economic situation general satisfaction or political preferences were not related to alcohol consumption.

CONCLUSIONS

While the overall levels of alcohol consumption appeared low, possibly due to under-reporting, the proportion of men who can be considered as "binge drinkers" was relatively high. The absence of sizable socio-economic differences suggest that drinking may be spread relatively uniformly in Russia, especially among males. Alcohol consumption seems unrelated to individuals' perception of the recent societal changes.

Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colon

BACKGROUND

Functional gut symptoms are induced by inclusion and reduced by dietary restriction of poorly absorbed short-chain carbohydrates (FODMAPs), but the mechanisms of action remain untested.

AIMS

To determine the effect of dietary FODMAPs on the content of water and fermentable substrates of ileal effluent.

METHODS

Twelve ileostomates without evidence of small intestinal disease undertook two 4-day dietary periods, comprising diets differing only in FODMAP content in a randomized, cross-over, single-blinded intervention study. Daytime (14 h) ileal effluent was collected on day four of each diet. Patients rated effluent volume and consistency on a 10-cm visual analogue scale. The FODMAP content of the diet and effluent was measured.

RESULTS

Ingested FODMAPs of 32% (range 6-73%) was recovered in the high FODMAP diet effluent. Effluent collection weight increased by a mean of 22% (95% CI, 5-39), water content by 20% (2-38%) and dry weight by 24% (4-43%) with the high compared to low FODMAP diet arm. Output increased by 95 (28-161) mL. Volunteers perceived effluent consistency was thicker (95% CI, 0.6-1.9) with the low FODMAP diet than with the high FODMAP diet (3.5-6.1; P = 0.006).

CONCLUSIONS

These data support the hypothetical mechanism; FODMAPs increase delivery of water and fermentable substrates to the proximal colon.

Dynamical configuration of binary near-Earth asteroid (66391) 1999 KW4

Dynamical simulations of the coupled rotational and orbital dynamics of binary near-Earth asteroid 66391 (1999 KW4) suggest that it is excited as a result of perturbations from the Sun during perihelion passages. Excitation of the mutual orbit will stimulate complex fluctuations in the orbit and rotation of both components, inducing the attitude of the smaller component to have large variation within some orbits and to hardly vary within others. The primary's proximity to its rotational stability limit suggests an origin from spin-up and disruption of a loosely bound precursor within the past million years.

Patterns of smoking in Russia

BACKGROUND

Tobacco is a leading cause of avoidable death in Russia but there is, as yet, relatively little information in the public domain on who is smoking and how this is changing. This information is important for those seeking to develop effective policies to tackle this issue.

OBJECTIVE

To determine the prevalence of smoking in Russia and its association with sociodemographic factors.

DESIGN

Cross-sectional survey on patterns of tobacco consumption.

SETTING

Data were collected using the New Russia Barometer, a multi-stage stratified-sample survey of the population of the Russian Federation undertaken in the summer of 1996.

PARTICIPANTS

Data were available on 1587 individuals (response rate 65.7%). Respondents differed little from the overall Russian population in terms of age, sex, education, and voting intention.

MAIN OUTCOME MEASURES

Prevalence of current and past smoking.

RESULTS

Smoking is common among males of all ages and in all areas. Of those aged 18-24 years, 65% smoke, rising to 73% in those aged 25-34 and then falling steadily to reach 41% in those aged 65 and older. Among women, smoking is much more common among the young (27% in those aged 18-34) than among the middle-aged and elderly (5% in those aged 55 and older), and more common among those living in urban areas than in rural areas. Smoking is also more common among men and women suffering material deprivation but there is no independent association with education. Among men, but not women, church attendance is inversely associated with smoking. In both sexes, but especially women, heavy drinking and smoking are associated.

CONCLUSIONS

Tobacco poses a major threat to the health of future generations in Russia, especially among women. A robust policy response is required.

Dietary sorbitol and mannitol: food content and distinct absorption patterns between healthy individuals and patients with irritable bowel syndrome

BACKGROUND

Sorbitol and mannitol are naturally-occurring polyol isomers. Although poor absorption and induction of gastrointestinal symptoms by sorbitol are known, the properties of mannitol are poorly described. We aimed to expand data on food composition of these polyols, and to compare their absorptive capacities and symptom induction in patients with irritable bowel syndrome (IBS) and healthy individuals.

METHODS

Food samples were analysed for sorbitol and mannitol content. The degree of absorption measured by breath hydrogen production and gastrointestinal symptoms (visual analogue scales) was evaluated in a randomised, double-blinded, placebo-controlled study in 21 healthy and 20 IBS subjects after challenges with 10 g of sorbitol, mannitol or glucose.

RESULTS

Certain fruits and sugar-free gum contained sorbitol, whereas mannitol content was higher in certain vegetables. Similar proportions of patients with IBS (40%) and healthy subjects (33%) completely absorbed sorbitol, although more so with IBS absorbed mannitol (80% versus 43%; P = 0.02). Breath hydrogen production was similar in both groups after lactulose but was reduced in patients with IBS after both polyols. No difference in mean (SEM) hydrogen production was found in healthy controls after sorbitol [area-under-the-curve: 2766 (591) ppm 4 h(-1) ] or mannitol [2062 (468) ppm 4 h(-1) ] but, in patients with IBS, this was greater after sorbitol [1136 (204) ppm 4 h(-1) ] than mannitol [404 (154) ppm 4 h(-1) ; P = 0.002]. Overall gastrointestinal symptoms increased significantly after both polyols in patients with IBS only, although they were independent of malabsorption of either of the polyols.

CONCLUSIONS

Increased and discordant absorption of mannitol and sorbitol occurs in patients with IBS compared to that in healthy controls. Polyols induced gastrointestinal symptoms in patients with IBS independently of their absorptive patterns, suggesting that the dietary restriction of polyols may be efficacious.

The importance of the relationship between scale and process in understanding long-term DOC dynamics

Concentrations of dissolved organic carbon have increased in many, but not all, surface waters across acid impacted areas of Europe and North America over the last two decades. Over the last eight years several hypotheses have been put forward to explain these increases, but none are yet accepted universally. Research in this area appears to have reached a stalemate between those favouring declining atmospheric deposition, climate change or land management as the key driver of long-term DOC trends. While it is clear that many of these factors influence DOC dynamics in soil and stream waters, their effect varies over different temporal and spatial scales. We argue that regional differences in acid deposition loading may account for the apparent discrepancies between studies. DOC has shown strong monotonic increases in areas which have experienced strong downward trends in pollutant sulphur and/or seasalt deposition. Elsewhere climatic factors, that strongly influence seasonality, have also dominated inter-annual variability, and here long-term monotonic DOC trends are often difficult to detect. Furthermore, in areas receiving similar acid loadings, different catchment characteristics could have affected the site specific sensitivity to changes in acidity and therefore the magnitude of DOC release in response to changes in sulphur deposition. We suggest that confusion over these temporal and spatial scales of investigation has contributed unnecessarily to the disagreement over the main regional driver(s) of DOC trends, and that the data behind the majority of these studies is more compatible than is often conveyed.

Morbidity/mortality and economics of hospital-acquired blood stream infections: a controlled study

A controlled study of mortality, length of hospital stay, and cost of hospitalization in 40 patients with hospital-acquired blood stream infections and 40 similarly ill patients without blood stream infections was done. Patients with septicemia were identified by ongoing routine surveillance, while controls were selected from computer surveys of similarly aged patients matched for primary diagnosis of operation or both. Bacteremic cases for which no matched controls could be obtained and 109 additional cases of blood stream infection occurring after the study period were also characterized to determine any gross bias in the process of case selection. Mortality in bacteremic patients was 38% compared to 10% in controls; median hospital stay was 33 days for bacteremic patients and cost was $6,692, compared to 14 days' hospitalization and $2,322 cost for controls. Mortality among the unmatched cases as well as the 109 additional cases was 34%. The excess morbidity, mortality, and hospitalization costs offer a better estimate of the direct effects of the hospital-acquired blood stream infection.

The value of constant surveillance in a risky environment

In risky environments, where threats are unpredictable and the quality of information about threats is variable, all individuals face two fundamental challenges: balancing vigilance against other activities, and determining when to respond to warning signals. The solution to both is to obtain continuous estimates of background risk, enabling vigilance to be concentrated during the riskiest periods and informing about the likely cost of ignoring warnings. Human surveillance organizations routinely produce such estimates, frequently derived from indirect cues. Here we show that vigilant individuals in an animal society (the pied babbler, Turdoides bicolor) perform a similar role. We ask (i) whether, in the absence of direct predator threats, pied babbler sentinels react to indirect information associated with increased risk and whether they communicate this information to group mates; (ii) whether group mates use this information to adjust their own vigilance, and whether this influences foraging success; and (iii) whether information provided by sentinels reduces the likelihood of inappropriate responses to alarm calls. Using playback experiments, we show that: (i) sentinels reacted to indirect predator cues (in the form of heterospecific alarm calls) by giving graded surveillance calls; (ii) foragers adjusted their vigilance in reaction to changes in surveillance calls, with substantial effects on foraging success; and (iii) foragers reduced their probability of responding to alarm calls when surveillance calls indicated lowered risk. These results demonstrate that identifying attacks as they occur is only part of vigilance: equally important is continuous surveillance providing information necessary for individuals to make decisions about their own vigilance and evasive action. Moreover, they suggest that a major benefit of group living is not only the increased likelihood of detecting threats, but a marked improvement in the quality of information available to each individual.

Comparison of the properties of Bacillus subtilis spores made in liquid or on agar plates

AIMS

To compare the properties of the spores of Bacillus subtilis prepared in liquid and on plates.

METHODS AND RESULTS

The spores of B. subtilis were prepared at 37 degrees C using a nutrient exhaustion medium either in liquid or on agar plates. The levels of core water, dipicolinic acid (DPA) and small, acid-soluble spore proteins (SASP) were essentially identical in spores made in liquid or on plates. Spores prepared in liquid were killed approximately threefold more rapidly at 90 degrees C in water than the spores prepared on plates, and the spores prepared in liquid were more sensitive to nitrous acid and a diluted stable superoxidized water. Spores prepared in liquid also germinated more rapidly with several agents than those prepared on plates. Pellets of spores prepared on plates were darker than spores prepared in liquid, and spores prepared in liquid had more readily extracted coat protein. However, there were no major differences in the relative levels of individual coat proteins or the cross-linking of the coat protein GerQ in the two types of spores, although the inner membrane of spores prepared on plates had a higher ratio of anteiso- to iso-fatty acids.

CONCLUSIONS

The preparation in liquid yielded spores with some different properties than those made on agar plates. Spores made in liquid had lower resistance to heat and several chemicals, and germinated more readily with several agents. There were also differences in the composition of the inner membrane of spores prepared under these two conditions. However, there were no major differences in the levels of DPA, core water, SASP and individual coat proteins or the cross-linking of a coat protein in spores made in liquid and on plates.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work demonstrates that the preparation method can affect the resistance and germination properties of bacterial spores, even if an identical medium and temperature are used. Evidence was also obtained consistent with the role of the inner membrane in spore resistance and germination, and that some factor in addition to core water, DPA and SASP content plays a role in spore resistance to wet heat.

Pesticides in honey bee colonies: Establishing a baseline for real world exposure over seven years in the USA

Honey bees Apis mellifera forage in a wide radius around their colony, bringing back contaminated food resources that can function as terrestrial bioindicators of environmental pesticide exposure. Evaluating pesticide exposure risk to pollinators is an ongoing problem. Here we apply five metrics for pesticide exposure risk (prevalence, diversity, concentration, significant pesticide prevalence, and hazard quotient (HQ)) to a nation-wide field study of honey bees, Apis mellifera in the United States. We examined samples from 1055 apiaries over seven years for 218 different pesticide residues and metabolites, determining that bees were exposed to 120 different pesticide products with a mean of 2.78 per sample. Pesticides in pollen were highly prevalent and variable across states. While pesticide diversity increased over time, most detections occurred at levels predicted to be of low risk to colonies. Varroacides contributed most to concentration, followed by fungicides, while insecticides contributed most to diversity above a toxicity threshold. High risk samples contained one of 12 different insecticides or varroacides. Exposures predicted to be low-risk were nevertheless associated with colony morbidity, and low-level fungicide exposures were tied to queen loss, Nosema infection, and brood diseases.

Asteroid 1950 DA's encounter with Earth in 2880: physical limits of collision probability prediction

Integration of the orbit of asteroid (29075) 1950 DA, which is based on radar and optical measurements spanning 51 years, reveals a 20-minute interval in March 2880 when there could be a nonnegligible probability of the 1-kilometer object colliding with Earth. Trajectory knowledge remains accurate until then because of extensive astrometric data, an inclined orbit geometry that reduces in-plane perturbations, and an orbit uncertainty space modulated by gravitational resonance. The approach distance uncertainty in 2880 is determined primarily by uncertainty in the accelerations arising from thermal re-radiation of solar energy absorbed by the asteroid. Those accelerations depend on the spin axis, composition, and surface properties of the asteroid, so that refining the collision probability may require direct inspection by a spacecraft.