It Takes a Village. Collaborative Outer Planet Missions

A mission to one or both of our local Ice Giants (Uranus and Neptune) emerged as a high priority in the most recent Planetary Science Decadal Survey and was also specifically mentioned supportively in the Heliophysics Decadal Survey. In 2016, NASA convened a science definition team to study ice giant mission concepts in more detail. Uranus and Neptune represent the last remaining planetary type in our Solar System to have a dedicated orbiting mission. The case for a Uranus mission has been made eloquently in the Decadal Surveys. Here we summarize some of the major drivers that lead to enthusiastic support for an Ice Giant mission in general, and use the example of a Uranus Mission concept to illustrate opportunities such a mission might provide for cross-division collaboration and cost-sharing

Unusual electron density profiles observed by Cassini radio occultations in Titan's ionosphere: Effects of enhanced magnetospheric electron precipitation?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95188/1/jgra21399.pd

Source mechanism of Saturn narrowband emission

Narrowband emission (NB) is observed at Saturn centered near 5 kHz and 20 kHz and harmonics. This emission appears similar in many ways to Jovian kilometric narrowband emission observed at higher frequencies, and therefore may have a similar source mechanism. Source regions of NB near 20 kHz are believed to be located near density gradients in the inner magnetosphere and the emission appears to be correlated with the occurrence of large neutral plasma clouds observed in the Saturn magnetotail. In this work we present the results of a growth rate analysis of NB emission (~20 kHz) near or within a probable source region. This is made possible by the sampling of in-situ wave and particle data. The results indicate waves are likely to be generated by the mode-conversion of directly generated Z-mode emission to O-mode near a density gradient. When the local hybrid frequency is close <I>n</I> <I>f</I>_ce (<I>n</I> is an integer and <I>f</I>_ce is the electron cyclotron frequency) with <I>n</I>=4, 5 or 6 in our case, electromagnetic Z-mode and weak ordinary (O-mode) emission can be directly generated by the cyclotron maser instability

Signatures of natural selection in a foundation tree along Mediterranean climatic gradients

Temperature and precipitation regimes are rapidly changing, resulting in forest dieback and extinction events, particularly in Mediterranean-type climates (MTC). Forest management that enhance forests’ resilience is urgently required, however adaptation to climates in heterogeneous landscapes with multiple selection pressures is complex. For widespread trees in MTC we hypothesized that: patterns of local adaptation are associated with climate; precipitation is a stronger factor of adaptation than temperature; functionally related genes show similar signatures of adaptation; and adaptive variants are independently sorting across the landscape. We sampled 28 populations across the geographic distribution of Eucalyptus marginata (jarrah), in South-west Western Australia, and obtained 13,534 independent single nucleotide polymorphic (SNP) markers across the genome. Three genotype-association analyses that employ different ways of correcting population structure were used to identify putatively adapted SNPs associated with independent climate variables. While overall levels of population differentiation were low (FST = 0.04), environmental association analyses found a total of 2336 unique SNPs associated with temperature and precipitation variables, with 1440 SNPs annotated to genic regions. Considerable allelic turnover was identified for SNPs associated with temperature seasonality and mean precipitation of the warmest quarter, suggesting that both temperature and precipitation are important factors in adaptation. SNPs with similar gene functions had analogous allelic turnover along climate gradients, while SNPs among temperature and precipitation variables had uncorrelated patterns of adaptation. These contrasting patterns provide evidence that there may be standing genomic variation adapted to current climate gradients, providing the basis for adaptive management strategies to bolster forest resilience in the future

The effect of Candida famata and Lactobacillus plantarum on the number of coliforms and the antibiotic resistance and virulence of Escherichia coli in the gut of broilers

This study was undertaken to determine the effect of a yeast (Candida famata) and a bacterium (Lactobacillus plantarum), administered alone or in combination in the drinking water, on the population of yeast, Lactobacillus sp. and coliforms, and the prevalence of antimicrobial resistance (AMR) and virulence genes in Escherichia coli (E. coli) isolated from digesta samples taken throughout the life of broiler chickens. Male (Ross 308) day-old chicks (220) were used. C. famata (isolated from a chicken) and L. plantarum (isolated from a pig) were administered via the drinking water. Water was provided either untreated or with C. famata (CF; 108 /ml), L. plantarum (LP; 105 –108 /ml), or a combination of CF and LP (106 –108 /ml) in water hoppers on 2 days each week for 35 days. Administering probiotics did not affect the growth performance in broiler chickens. No significant interactions were observed between main effects, and neither CF nor LP had any effect on the population size of Lactobacillus sp. or coliforms. The administration of C. famata increased the population density of yeasts in the small intestine at these ages. The population density of coliforms, Lactobacillus sp. and yeast decreased with age (P < 0.001). There was no significant effect of probiotics on the prevalence of phenotypic AMR and virulence genes in these studies. The prevalence of E. coli that was resistant to ampicillin and tetracycline, as well as carrying ≥3 virulence-associated genes, was greatest at the end of the starter phase (around 8 days old), before declining through the grower and finisher phases. There was only limited evidence that administering either CF or LP affected either the AMR or the virulence of E. coli in the bird. However, tetracycline resistance in E. coli was associated (P < 0.001, P < 0.01, P < 0.05, and P < 0.05) with the carriage of the iron uptake systems of E. coli D, iron-repressible protein, increased serum survival and temperaturesensitive haemagglutinin genes respectively, suggesting that the accumulation of iron and the genetic element conferring tetracycline resistance may be intertwined

Melomys cervinipes (Rodentia: Muridae)

Melomys cervinipes (Gould, 1852) is a murid rodent commonly called the fawn-footed mosaic-tailed rat. A small, russet brown rodent with light fawn-colored feet, it is 1 of 21 currently recognized species in the genus Melomys. The species is endemic to Australia, occurring in the rainforests and forests along the eastern coast. M. cervinipes is listed as "Least Concern" by the International Union for the Conservation of Nature and Natural Resources

Binding Mechanism of Metal⋅NTP Substrates and Stringent-Response Alarmones to Bacterial DnaG-Type Primases

SummaryPrimases are DNA-dependent RNA polymerases found in all cellular organisms. In bacteria, primer synthesis is carried out by DnaG, an essential enzyme that serves as a key component of DNA replication initiation, progression, and restart. How DnaG associates with nucleotide substrates and how certain naturally prevalent nucleotide analogs impair DnaG function are unknown. We have examined one of the earliest stages in primer synthesis and its control by solving crystal structures of the S. aureus DnaG catalytic core bound to metal ion cofactors and either individual nucleoside triphosphates or the nucleotidyl alarmones, pppGpp and ppGpp. These structures, together with both biochemical analyses and comparative studies of enzymes that use the same catalytic fold as DnaG, pinpoint the predominant nucleotide-binding site of DnaG and explain how the induction of the stringent response in bacteria interferes with primer synthesis

Antimicrobial in vitro activities of condensed tannin extracts on avian pathogenic Escherichia coli

Condensed tannins (CTs), which extracted from yew leaves, tilia flower and black locust leaves, were examined for their antimicrobial in vitro activity against avian pathogenic Escherichia coli (APEC). Past research demonstrated that CTs which contain procyanidins and prodelphinidins that could inhibit the growth of a wide range of bacteria. However, there is no information on how these affect pathogenic bacteria from chickens such as APEC. The high concentration of extracts, 10, 5, 2.5 mg/ml, affected the growth curves of APEC, which gave different inhibition values for the three CT extracts. Further, these CTs had significant effects (P≤0.05) on APEC biofilm and motility depending on each CT concentration and composition. However, at low concentration (0.6 mg/ml), the tilia flowers, a high molar percentage of procyanidins, enhanced bacterial cell attachment and improved the swimming motility of APEC. In contrast, yew, an equal molar percentage of procyanidins/prodelphinidins, and black locust, a high molar percentage of prodelphinidins, interrupted and blocked swarming and swimming motility. The data suggested that the antimicrobial activity of the CT extracts was elicited by a positive relationship between anti-biofilm formation and anti-motility capacities

Bioclimatic transect networks: powerful observatories of ecological change

First published: 19 May 2017Transects that traverse substantial climate gradients are important tools for climate change research and allow questions on the extent to which phenotypic variation associates with climate, the link between climate and species distributions, and variation in sensitivity to climate change among biomes to be addressed. However, the potential limitations of individual transect studies have recently been highlighted. Here, we argue that replicating and networking transects, along with the introduction of experimental treatments, addresses these concerns. Transect networks provide cost-effective and robust insights into ecological and evolutionary adaptation and improve forecasting of ecosystem change. We draw on the experience and research facilitated by the Australian Transect Network to demonstrate our case, with examples, to clarify how population- and community-level studies can be integrated with observations from multiple transects, manipulative experiments, genomics, and ecological modeling to gain novel insights into how species and systems respond to climate change. This integration can provide a spatiotemporal understanding of past and future climate-induced changes, which will inform effective management actions for promoting biodiversity resilience.Stefan Caddy-Retalic, Alan N. Andersen, Michael J. Aspinwall, Martin F. Breed, Margaret Byrne, Matthew J. Christmas, Ning Dong, Bradley J. Evans, Damien A. Fordham, Greg R. Guerin, Ary A. Hoffmann, Alice C. Hughes, Stephen J. van Leeuwen, Francesca A. McInerney, Suzanne M. Prober, Maurizio Rossetto, Paul D. Rymer, Dorothy A. Steane, Glenda M. Wardle, Andrew J. Low

Assessment of Different Tannin Extracts on Avian Pathogenic Escherichia coli Metabolites Using Nuclear Magnetic Resonance

Tannins have been demonstrated to inhibit the growth of several chicken illnesses in vitro. The complex compositions of tannins make it difficult for microorganisms to develop bacterial resistance. This study aimed to evaluate the effect of condensed tannins (CT) extracts on metabolic profile of Avian Pathogenic Escherichia coli (APEC) using Nuclear Magnetic Resonance (1H-NMR). The experimental groups were divided into three groups:control (no CT added), high in procyanidins (PC-CT) group, and high in prodelphinidins (PDCT) group, with exposure times of 0, 10, and 24 h. APEC was observed to respond to CT extracted from Tilia flowers (high PC-CT) and black locust leaves (high PD-CT). The levels of amino acids including lysine, leucine, glutamate, phenylalanine, and pyroglutamate were increased with the high PD-CT treatment; however, no significant differences were observed between the PC-CT group and the control. Treatment of APEC culture with high PD-CT also led to a significant decrease in the level of lactate. Thus, high PD-CT affected these metabolisms and could be exploited to control the proliferation of APEC in poultry, thereby improving their health and performance