Sexual Plant Reproduction： a Fertile and Flourishing Field

Since the very beginning of plant science, sexual plant reproduction （SPR） has proved an attractive and enduring topic for generations of botanists. With the rapid development of modern technology, a significant acceleration has occurred in our understanding on the developmental mechanisms of plant reproductive processes, particularly the evolution of double fertilisation, signalling in pollen tube orientation, molecular characterisation of plant gametes, maternal to zygotic transitions and parental gene involvement in early embryogenesis. This is reflected not only by several recent high-ranking research papers, but also by the frequent conferences and workshops on these topics. These include the 2008 XXth International Congress on SPR in Brasilia and ＂Frontiers in SPR Ⅲ＂ in Tucson, as well as ＂Cell- Cell Communication in Plant Reproduction＂ held in 2009 in Bath. The continuing efforts from around the world indicate that SPR is still a fertile and flourishing field, with great expectations for the coming decade.     

Conferences in the Field of Virology Invitation·Main Programme

正2016·2017|Erlangen(DE)·Marburg(DE)Dear Sir or Madam,Dear colleague,We would like to give you a brief overview of upcoming virological conferences.You are cordially invited to join and visit us in Erlangen and Marburg(Germany).Frontiers of Retrovirology Conference 201612-14September 2016·Erlangen(DE)·www.frontiers-of-retrovirology.com     

Field metabolic rates of instrumented Adélie penguins using double-labelled water

Summary Adélie penguins (Pygoscelis adeliae) carrying dummy instruments were used to determine field metabolic rates using double-labelled water. All penguins injected with double-labelled water showed a marked loss of body mass (-4.5%) during the period of the experiments (20–131 h), irrespective of the time of the breeding season. Total body water averaged 57.3% and water flux estimates of field metabolic rates correlated with double-labelled water estimates of field metabolic rate (r ²=0.68), indicating that Adélie penguins do not ingest significant amounts of sea water. Brooding Adélie penguins had a mean field metabolic rate of 10.1 W·kg^-1 and at sea a field metabolic rate of 13.3 W·kg^-1, both of which compare well with previously published estimates based on time/activity budgets and respirometry. Mean field metabolic rate in penguins with crèching chicks was 14.1 W·kg^-1, and the birds spent 65 h absent from the nest as opposed to previous estimates of 7.1 W·kg^-1 and 21 h. The effects of weather, disturbance and manipulation on the behaviour and field metabolic rate of penguins late in the breeding season are discussed. Adélie penguins (crèching chicks) equipped with externally attached instruments spent more time absent from the nest than noninstrumented controls (76 vs 54 h), but had a lower field metabolic rate.Abbreviations ANOVA analysis of variance - DLW double-labelled water - FMR field metabolic rate - MR metabolic rate - RMR resting metabolic rate - TBW total body water - VSMOW Vienna standard mean ocean water - WF water flux     

Cell Polarity: Which Way to Grow in an Electric Field?

Cell polarity can be influenced by an electric field, but the mechanisms behind this response are poorly understood. A new paper shows that fission yeast cells change their direction of growth in an external electric field and suggests mechanisms based on the cortical pH gradient and on electrophoresis of membrane proteins.     

Ultra-Uniform Field Distribution in a Finite-Width Metal–Dielectric–Metal Waveguide

We investigate the propagation characteristics of the fundamental surface plasmon polariton (SPP) mode of a finite-width metal–dielectric–metal waveguide. By changing the refractive index or the thickness of the dielectric layer of the waveguide, the SPP mode can be transformed from a mode confined in the dielectric layer into a mode confined around the metal corners. There always exists a condition at which the mode field distribution in the dielectric layer becomes almost perfectly uniform along the direction parallel to the metal layers, and this condition is insensitive to the width of the waveguide. It is also possible to obtain an ultra-uniform field distribution by controlling the refractive index of a different dielectric placed on both sides of the waveguide. The waveguide can be used as a basic structure for the realization of nanosized photonic devices and sensors.     

Frequency-Dependent Polarization Properties of Local Electric Field in Gold–Dielectric Multi-Nanoshells

The polarization properties of the local electric field in the gold–dielectric–gold multilayer nanoshells are investigated by theoretical calculation based on the quasi-static approximation. The calculation results show that the complete polarized incident light does not only stimulate the same directional polarized local electric field. The polarized angle of the local field may changes from 0° to 90° as the wavelength and location are changed. The distributions of local field polarization are different in dielectric layer or gold shell and display different features in different plasmonic hybridization mode. As the incident wavelength is increased, the hot spot of polarizing angle moves monotonously in the middle dielectric shell, whereas moves nonmonotonously in the gold shell and surrounding environment. In the gold shell, the gap between hot spots of polarizing angle may occur at the resonance frequency. However, the hot spots of polarizing angle always occur at the resonance frequencies in the surrounding environment. These interesting results show that the single-molecule detection based on metal nanostructure induced surface-enhanced Raman scattering and surface enhanced fluorescence could be optimized by adjusting the incident light polarization and frequency.     

Formation of γ-BTC in Flooded Rice Field Soils Treated with γ-BHC

The amino acids of the B-chains of two abrins (designated as abrin-a and abrin-b) from the seeds of Abrus precatorius have been sequenced. The sequence of the B-chain of abrin-a was solved by analysis of peptides derived by enzymatic digestions with trypsin, Iysylendopeptidase, and chymotrypsin, as well as by chemical cleavage with cyanogen bromide. The sequence of the B-chain of abrin-b was analyzed by sequence analysis of tryptic peptides and comparing these sequences with those of corresponding peptides of the B-chain of abrin-a. The B-chains of abrin-a and abrin-b consist of 268 amino acid residues and share 256 identical residues. Comparison of their sequences with that of the ricin B-chain shows that 60% of the residues of both abrin B-chains are identical to those of the ricin B-chain and that two saccharide-binding sites in ricin B-chain identified by a crystallographic study are highly conserved in both abrin B-chains.     

Field observations on the lepidophagous teleost Terapon jarbua (Forsk»l)

Synopsis Foraging behaviour of the lepidophagous Indo-Pacific teleost Terapon jarbua in the Bulolo and Mtumbane estuaries of southern Africa is described. These observations suggest that scale removal from large fish and the complete ingestion of fish fry represents a modified form of predation. Prey reaction to T. jarbua shoals is also discussed.     

Effect of the “zero” Magnetic Field on Early Embryogenesis in Mice

It was shown that the 250-fold screening of the geomagnetic field (GMF) (“zero” magnetic field with an induction of 0.2?μT) affects early embryogenesis and the reproduction capacity of mice in vivo. Pregnant NMRI mice at the zygote stage placed in this “zero” magnetic field (MF) lost the ability to bear offspring babies although their embryos developed up to the blastocyst stage without any visible deviations from the norm. The abortion of development in the “zero” MF occurred after the exit of the blastocysts from the zona pellicida and invasion into the uterus during implantation. Histological analysis indicates that possible reasons of the abnormalities of postimplantation development are a decrease in the proliferative activity of embryonic cells and the impairment of the interaction between the trophoblast and endometrium, which finally results in the resorption of embryos in the uterus.     

POLIOMYELITIS VACCINE—A Report on Field Trials in Southern Alameda County in 1954

Southern Alameda County was the only area in California to take part in the 1954 nationwide field trials for testing poliomyelitis vaccine. Besides the contribution made in evaluating the vaccine, other benefits were:1. Participation contributed to the control of a serious communicable disease.2. Inoculations of vaccine during the field trials in all probability prevented some cases of paralytic poliomyelitis among children in southern Alameda County.3. The community became better informed about poliomyelitis and more interested in the local health department.4. Local physicians had an opportunity to contribute to important research and to give a valuable community service.5. The staff of the Alameda County Health Department became better informed and better prepared for any future responsibilities in poliomyelitis immunization programs.Other conclusions reached as a result of participation in the 1954 field trials are that the initial planning of the study was hasty and not sufficiently representative of medical and administrative thinking. If the trials had been planned for 1955 instead of 1954 there would have been sufficient time for research to be completed, professional information to be assured and for sound design of study.     

Labs in the Field? Rocky Mountain Biological Stations in the Early Twentieth Century

Biological field stations proliferated in the Rocky Mountains region of the western United States during the early decades of the twentieth century. This essay examines these Rocky Mountain field stations as hybrid lab-field sites from the perspective of the field side of the dichotomy: as field sites with raised walls rather than as laboratories whose walls with the natural world have been lowered. Not only were these field stations transformed to be more like laboratories, but they were also embedded within the particular regional environmental and institutional context of the Rocky Mountains. Using the University of Colorado's Mountain Laboratory at Tolland and other contemporaneous sites as examples, this essay analyzes key features of these sites, including their location within transportation networks, buildings, equipment, personnel, scheduling, recreational and social activities, and other material and social practices on the ground. Considering both the distinctive and shared characteristics of the Rocky Mountain field stations in comparison to other types of field stations provides a more complete picture of the diversity and range of lab-field hybrid sites in the biological sciences in the early twentieth-century United States.     

Abundance and Borrelia burgdorferi-infection Prevalence of Nymphal Ixodes scapularis Ticks along Forest–Field Edges

More than 19,000 human cases of Lyme disease (LD) are reported each year in the United States. Lyme disease cases occur when humans are exposed to the bacterium Borrelia burgdorferi through the bite of an infected ixodid tick. The probability of human exposure to infected ticks results from a combination of human behaviors and entomological risk. Human behaviors include use of tick habitats, use of protective clothing, and grooming for tick removal. Entomological risks include the density of ticks in a habitat and the proportion of these that are infected with B. burgdorferi. Recent studies have suggested that humans are at higher risk of exposure to B. burgdorferi near edges between forests and herbaceous communities, including lawns and old fields, but whether this increased risk is a function of human behaviors, entomological risk, or both, is unknown. We assessed entomological risk across forest–old field edges in Dutchess County, NY. Densities of ticks and of infected ticks were considerably higher within forests than at forest–field edges, and were lowest within fields. Thus, edges between forests and fields do not pose a higher entomological risk than do the forests themselves, although risk at the edge is higher than in herbaceous habitat. Landscapes with abundant edges between forested and herbaceous habitat, and roughly even proportions of both, might attract both heavy human use and pose moderately high entomological risk, and thus could be targeted for mitigation. We suggest that determining appropriate methods for reducing human exposure to LD requires differentiating entomological risk from human behaviors.     

Fulfilling the Promise of Personalized Medicine? Systematic Review and Field Synopsis of Pharmacogenetic Studies

Background

Studies of the genetic basis of drug response could help clarify mechanisms of drug action/metabolism, and facilitate development of genotype-based predictive tests of efficacy or toxicity (pharmacogenetics).

Objectives

We conducted a systematic review and field synopsis of pharmacogenetic studies to quantify the scope and quality of available evidence in this field in order to inform future research.

Data Sources

Original research articles were identified in Medline, reference lists from 24 meta-analyses/systematic reviews/review articles and U.S. Food and Drug Administration website of approved pharmacogenetic tests.

Study Eligibility Criteria, Participants, and Intervention Criteria

We included any study in which either intended or adverse response to drug therapy was examined in relation to genetic variation in the germline or cancer cells in humans.

Study Appraisal and Synthesis Methods

Study characteristics and data reported in abstracts were recorded. We further analysed full text from a random 10% subset of articles spanning the different subclasses of study.

Results

From 102,264 Medline hits and 1,641 articles from other sources, we identified 1,668 primary research articles (1987 to 2007, inclusive). A high proportion of remaining articles were reviews/commentaries (ratio of reviews to primary research approximately 25∶1). The majority of studies (81.8%) were set in Europe and North America focussing on cancer, cardiovascular disease and neurology/psychiatry. There was predominantly a candidate gene approach using common alleles, which despite small sample sizes (median 93 [IQR 40–222]) with no trend to an increase over time, generated a high proportion (74.5%) of nominally significant (p<0.05) reported associations suggesting the possibility of significance-chasing bias. Despite 136 examples of gene/drug interventions being the subject of ≥4 studies, only 31 meta-analyses were identified. The majority (69.4%) of end-points were continuous and likely surrogate rather than hard (binary) clinical end-points.

Conclusions and Implications of Key Findings

The high expectation but limited translation of pharmacogenetic research thus far may be explained by the preponderance of reviews over primary research, small sample sizes, a mainly candidate gene approach, surrogate markers, an excess of nominally positive to truly positive associations and paucity of meta-analyses. Recommendations based on these findings should inform future study design to help realise the goal of personalised medicines.

Systematic Review Registration Number

Not Registered     

How Much Remains Undetected? Probability of Molecular Detection of Human Plasmodia in the Field

Background

In malaria endemic areas, most people are simultaneously infected with different parasite clones. Detection of individual clones is hampered when their densities fluctuate around the detection limit and, in case of P. falciparum, by sequestration during part of their life cycle. This has important implications for measures of levels of infection or for the outcome of clinical trials. This study aimed at measuring the detectability of individual P. falciparum and P. vivax parasite clones in consecutive samples of the same patient and at investigating the impact of sampling strategies on basic epidemiological measures such as multiplicity of infection (MOI).

Methods

Samples were obtained in a repeated cross-sectional field survey in 1 to 4.5 years old children from Papua New Guinea, who were followed up in 2-monthly intervals over 16 months. At each follow-up visit, two consecutive blood samples were collected from each child at intervals of 24 hours. Samples were genotyped for the polymorphic markers msp2 for P. falciparum and msp1F3 and MS16 for P. vivax. Observed prevalence and mean MOI estimated from single samples per host were compared to combined data from sampling twice within 24 h.

Findings and Conclusion

Estimated detectability was high in our data set (0.79 [95% CI 0.76–0.82] for P. falciparum and, depending on the marker, 0.61 [0.58–0.63] or 0.73 [0.71–0.75] for P. vivax). When genotyping data from sequential samples, collected 24 hours apart, were combined, the increase in measured prevalence was moderate, 6 to 9% of all infections were missed on a single day. The effect on observed MOI was more pronounced, 18 to 31% of all individual clones were not detected in a single bleed. Repeated sampling revealed little difference between detectability of P. falciparum and P. vivax.