Global ecosystems and fire: Multi‐model assessment of fire‐induced tree‐cover and carbon storage reduction

In this study, we use simulations from seven global vegetation models to provide the first multi‐model estimate of fire impacts on global tree cover and the carbon cycle under current climate and anthropogenic land use conditions, averaged for the years 2001–2012. Fire globally reduces the tree covered area and vegetation carbon storage by 10%. Regionally, the effects are much stronger, up to 20% for certain latitudinal bands, and 17% in savanna regions. Global fire effects on total carbon storage and carbon turnover times are lower with the effect on gross primary productivity (GPP) close to 0. We find the strongest impacts of fire in savanna regions. Climatic conditions in regions with the highest burned area differ from regions with highest absolute fire impact, which are characterized by higher precipitation. Our estimates of fire‐induced vegetation change are lower than previous studies. We attribute these differences to different definitions of vegetation change and effects of anthropogenic land use, which were not considered in previous studies and decreases the impact of fire on tree cover. Accounting for fires significantly improves the spatial patterns of simulated tree cover, which demonstrates the need to represent fire in dynamic vegetation models. Based upon comparisons between models and observations, process understanding and representation in models, we assess a higher confidence in the fire impact on tree cover and vegetation carbon compared to GPP, total carbon storage and turnover times. We have higher confidence in the spatial patterns compared to the global totals of the simulated fire impact. As we used an ensemble of state‐of‐the‐art fire models, including effects of land use and the ensemble median or mean compares better to observational datasets than any individual model, we consider the here presented results to be the current best estimate of global fire effects on ecosystems.     

Family Planning Knowledge,Attitude and Practice among Married Couples in Jimma Zone,Ethiopia

Background

Understanding why people do not use family planning is critical to address unmet needs and to increase contraceptive use. According to the Ethiopian Demographic and Health Survey 2011, most women and men had knowledge on some family planning methods but only about 29% of married women were using contraceptives. 20% women had an unmet need for family planning. We examined knowledge, attitudes and contraceptive practice as well as factors related to contraceptive use in Jimma zone, Ethiopia.

Methods

Data were collected from March to May 2010 among 854 married couples using a multi-stage sampling design. Quantitative data based on semi-structured questionnaires was triangulated with qualitative data collected during focus group discussions. We compared proportions and performed logistic regression analysis.

Result

The concept of family planning was well known in the studied population. Sex-stratified analysis showed pills and injectables were commonly known by both sexes, while long-term contraceptive methods were better known by women, and traditional methods as well as emergency contraception by men. Formal education was the most important factor associated with better knowledge about contraceptive methods (aOR = 2.07, p<0.001), in particular among women (aOR_women = 2.77 vs. aOR_men = 1.49; p<0.001). In general only 4 out of 811 men ever used contraception, while 64% and 43% females ever used and were currently using contraception respectively.

Conclusion

The high knowledge on contraceptives did not match with the high contraceptive practice in the study area. The study demonstrates that mere physical access (proximity to clinics for family planning) and awareness of contraceptives are not sufficient to ensure that contraceptive needs are met. Thus, projects aiming at increasing contraceptive use should contemplate and establish better counseling about contraceptive side effects and method switch. Furthermore in all family planning activities both wives'' and husbands'' participation should be considered.     

The Contribution of Emotional Partners to Sexual Risk Taking and Violence among Female Sex Workers in Mombasa,Kenya: A Cohort Study

Objectives

To assess sexual risk-taking of female sex workers (FSWs) with emotional partners (boyfriends and husbands), compared to regular and casual clients. Experiences of violence and the degree of relationship control that FSWs have with emotional partners are also described.

Design

Cohort study with quarterly follow-up visit over 12-months.

Methods

Four hundred HIV-uninfected FSWs older than 16 years were recruited from their homes and guesthouses in Mombasa, Kenya. A structured questionnaire assessed participant characteristics and study outcomes at each visit, and women received risk-reduction counselling, male and female condoms, and HIV testing.

Results

Four or more unprotected sex acts in the past week were reported by 21.3% of women during sex with emotional partners, compared to 5.8% with regular and 4.8% with casual clients (P<0.001). Total number of unprotected sex acts per week was 5–6-fold higher with emotional partners (603 acts with 259 partners) than with regular or casual clients (125 acts with 456, and 98 acts with 632 clients, respectively; P<0.001). Mostly, perceptions of “trust” underscored unprotected sex with emotional partners. Low control over these relationships, common to many women (36.9%), was linked with higher partner numbers, inconsistent condom use, and being physically forced to have sex by their emotional partners. Half experienced sexual or physical violence in the past year, similarly associated with partner numbers and inconsistent condom use.

Conclusions

High-risk sexual behaviour, low control and frequent violence in relationships with emotional partners heighten FSWs'' vulnerability and high HIV risk, requiring targeted interventions that also encompass emotional partners.     

Nesidiocoris tenuis as a pest in Northwest Europe: Intervention threshold and influence of Pepino mosaic virus

The use of Nesidiocoris tenuis (Hemiptera: Miridae) as a biocontrol agent is controversial as it is considered a pest in Northwest European tomato greenhouses, due to its tendency to damage the plant and fruit. Necessary chemical plant protection products to control N. tenuis have toxic side effects on important beneficials like Macrolophus pygmaeus (Hemiptera: Miridae), which jeopardizes the whole IPM programme. In this study, several commercial tomato greenhouses were monitored for mirid populations. The relationship between the number of N. tenuis individuals and plant damage was assessed in function of availability of prey and interaction with M. pygmaeus. These greenhouse data were used to determine a practical density intervention threshold. Next, the hypothesis that a Pepino mosaic virus (PepMV) infection increases plant and fruit damage by N. tenuis (as has been shown for M. pygmaeus) was tested. Plant damage occurred when the average number of predatory bugs in the head of the plant exceeded 16 per ten plants. Plant damage increased in severity at increasing predatory bug densities, independent of the availability of prey and M. pygmaeus presence. Plant and fruit damage were not affected by the presence of PepMV, as was shown for fruit damage in previous studies for M. pygmaeus. Our study provides a practical density intervention threshold for growers in greenhouse crops. Simple monitoring of the number of predatory bugs in the head of the plant can be used to take specific biocontrol actions. It was also shown that only the predatory bug N. tenuis itself causes damage, and there is no interaction with PepMV.     

Molecular mechanism of allosteric substrate activation in a thiamine diphosphate-dependent decarboxylase

Thiamine diphosphate-dependent enzymes are involved in a wide variety of metabolic pathways. The molecular mechanism behind active site communication and substrate activation, observed in some of these enzymes, has since long been an area of debate. Here, we report the crystal structures of a phenylpyruvate decarboxylase in complex with its substrates and a covalent reaction intermediate analogue. These structures reveal the regulatory site and unveil the mechanism of allosteric substrate activation. This signal transduction relies on quaternary structure reorganizations, domain rotations, and a pathway of local conformational changes that are relayed from the regulatory site to the active site. The current findings thus uncover the molecular mechanism by which the binding of a substrate in the regulatory site is linked to the mounting of the catalytic machinery in the active site in this thiamine diphosphate-dependent enzyme.     

Exploring neuropeptide signalling through proteomics and peptidomics

Introduction: Neuropeptides are neuro-endocrine signaling molecules capable of signaling as neurotransmitters, neuromodulators or neurohormones. Studying how neuropeptide signaling is integrated in endocrine pathways and how neuropeptides regulate endogenous processes is crucial to understanding how multicellular organisms respond to environmental and internal cues.

Areas covered: This review will cover proteomics and peptidomics approaches used in researching peptide signaling systems and breakthroughs that were achieved in this field. Both differential mass spectrometry and reverse genetic approaches are commonly used to study neuropeptidergic signaling. The field of proteomics quickly developed in the past decades and expanded from gel-based approaches to include advanced liquid chromatography and mass spectrometry. We explore how proteomics is used to reveal neuropeptide maturation and identify downstream targets of neuropeptide signaling pathways. We show how peptidomics differs from standard proteomics approaches and how it is used to study both neuropeptide processing and signal pathway identification.

Expert commentary: Thanks to recent advancements in isolation techniques and increased sensitivity of equipment, proteomics and peptidomics studies of neuropeptide signaling are contributing increasingly to elucidating functional implications of endocrine signaling. Further technical progress should allow for full peptidomic profiling of single neurons, eventually providing us with a complete comprehension of endocrine signaling.     

Unveiling the nonlinear optical response of Trictenotoma childreni longhorn beetle

The wings of some insect species are known to fluoresce under illumination by ultraviolet light. Their fluorescence properties are however, not comprehensively documented. In this article, the optical properties of one specific insect, the Trictenotoma childreni yellow longhorn beetle, were investigated using both linear and nonlinear optical (NLO) methods, including one‐ and two‐photon fluorescence and second harmonic generation (SHG). These three distinct optical signals discovered in this beetle are attributed to the presence of fluorophores embedded within the scales covering their elytra. Experimental evidence collected in this study indicates that the fluorophores are non‐centrosymmetric, a fundamental requirement for SHG. This study is the first reported optical behavior of this type in insects. We described how NLO techniques can complement other more convenient approaches to achieve a more comprehensive understanding of insect scales and integument properties.      

High‐resolution time‐resolved imaging of in vitro Arabidopsis rosette growth

Although quantitative characterization of growth phenotypes is of key importance for the understanding of essential networks driving plant growth, the majority of growth‐related genes are still being identified based on qualitative visual observations and/or single‐endpoint quantitative measurements. We developed an in vitro growth imaging system (IGIS) to perform time‐resolved analysis of rosette growth. In this system, Arabidopsis plants are grown in Petri dishes mounted on a rotating disk, and images of each plate are taken on an hourly basis. Automated image analysis was developed in order to obtain several growth‐related parameters, such as projected rosette area, rosette relative growth rate, compactness and stockiness, over time. To illustrate the use of the platform and the resulting data, we present the results for the growth response of Col–0 plants subjected to three mild stress conditions. Although the reduction in rosette area was relatively similar at 19 days after stratification, the time‐lapse analysis demonstrated that plants react differently to salt, osmotic and oxidative stress. The rosette area was altered at various time points during development, and leaf movement and shape parameters were also affected differently. We also used the IGIS to analyze in detail the growth behavior of mutants with enhanced leaf size. Analysis of several growth‐related parameters over time in these mutants revealed several specificities in growth behavior, underlining the high complexity of leaf growth coordination. These results demonstrate that time‐resolved imaging of in vitro rosette growth generates a better understanding of growth phenotypes than endpoint measurements.