Inhibition of type I interferon induction and signalling by mosquito‐borne flaviviruses

The Flavivirus genus (Flaviviridae family) contains a number of important human pathogens, including dengue and Zika viruses, which have the potential to cause severe disease. In order to efficiently establish a productive infection in mammalian cells, flaviviruses have developed key strategies to counteract host immune defences, including the type I interferon response. They employ different mechanisms to control interferon signal transduction and effector pathways, and key research generated over the past couple of decades has uncovered new insights into their abilities to actively decrease interferon antiviral activity. Given the lack of antivirals or prophylactic treatments for many flaviviral infections, it is important to fully understand how these viruses affect cellular processes to influence pathogenesis and disease outcome. This review will discuss the strategies mosquito‐borne flaviviruses have evolved to antagonise type I interferon mediated immune responses.     

Nesting,brood rearing,and summer habitat selection by translocated greater sage‐grouse in North Dakota,USA

Human enterprise has led to large‐scale changes in landscapes and altered wildlife population distribution and abundance, necessitating efficient and effective conservation strategies for impacted species. Greater sage‐grouse (Centrocercus urophasianus; hereafter sage‐grouse) are a widespread sagebrush (Artemisia spp.) obligate species that has experienced population declines since the mid‐1900s resulting from habitat loss and expansion of anthropogenic features into sagebrush ecosystems. Habitat loss is especially evident in North Dakota, USA, on the northeastern fringe of sage‐grouse’ distribution, where a remnant population remains despite recent development of energy‐related infrastructure. Resource managers in this region have determined a need to augment sage‐grouse populations using translocation techniques that can be important management tools for countering species decline from range contraction. Although translocations are a common tool for wildlife management, very little research has evaluated habitat following translocation, to track individual behaviors such as habitat selection and fidelity to the release site, which can help inform habitat requirements to guide selection of future release sites. We provide an example where locations from previously released radio‐marked sage‐grouse are used in a resource selection function framework to evaluate habitat selection following translocation and identify areas of seasonal habitat to inform habitat management and potential restoration needs. We also evaluated possible changes in seasonal habitat since the late 1980s using spatial data provided by the Rangeland Analysis Platform coupled with resource selection modeling results. Our results serve as critical baseline information for habitat used by translocated individuals across life stages in this study area, and will inform future evaluations of population performance and potential for long‐term recovery.     

Drosophila FANCM Helicase Prevents Spontaneous Mitotic Crossovers Generated by the MUS81 and SLX1 Nucleases

Several helicases function during repair of double-strand breaks and handling of blocked or stalled replication forks to promote pathways that prevent formation of crossovers. Among these are the Bloom syndrome helicase BLM and the Fanconi anemia group M (FANCM) helicase. To better understand functions of these helicases, we compared phenotypes of Drosophila melanogaster Blm and Fancm mutants. As previously reported for BLM, FANCM has roles in responding to several types of DNA damage in preventing mitotic and meiotic crossovers and in promoting the synthesis-dependent strand annealing pathway for repair of a double-strand gap. In most assays, the phenotype of Fancm mutants is less severe than that of Blm mutants, and the phenotype of Blm Fancm double mutants is more severe than either single mutant, indicating both overlapping and unique functions. It is thought that mitotic crossovers arise when structure-selective nucleases cleave DNA intermediates that would normally be unwound or disassembled by these helicases. When BLM is absent, three nucleases believed to function as Holliday junction resolvases—MUS81-MMS4, MUS312-SLX1, and GEN—become essential. In contrast, no single resolvase is essential in mutants lacking FANCM, although simultaneous loss of GEN and either of the others is lethal in Fancm mutants. Since Fancm mutants can tolerate loss of a single resolvase, we were able to show that spontaneous mitotic crossovers that occur when FANCM is missing are dependent on MUS312 and either MUS81 or SLX1.     

Distribution of N within Pea, Lupin, and Soybean Nodules

The ¹⁵N abundance of some, but not all, legume root nodules is significantly elevated compared to that of the whole plant. It seems probable that differences in ¹⁵N enrichment reflect differences in the assimilatory pathway of fixed N. In that context, we have determined the distribution of naturally occurring ¹⁵N in structural fractions of nodules from soybean (Glycine max L. Merr.), yellow lupin (Lupinus luteus), and pea (Pisum sativum) nodules and in chemical components from soybean nodules and to a lesser extent, pea and lupin nodules. None of the fractions of pea nodules (cortex, bacteriod, or host plant cytoplasm) was enriched in ¹⁵N. The differences among bacteriods, cortex, and plant cytoplasm were smaller in lupin than in soybean nodules, but in both, bacteriods had the highest ¹⁵N enrichment. In soybean nodules, the ¹⁵N abundance of bacteriods and cortex was higher than plant cytoplasm, but all three fractions were more enriched in ¹⁵N than the entire plant. Plant cytoplasm from soybean nodules was fractionated into protein-rich material, nonprotein alcohol precipitable material (NA), and a low molecular weight fraction. The N of the latter was further separated into N of ureides, nucleotides and free amino acids. Most of these components were either similar to or lower in ¹⁵N abundance than the plant cytoplasm as a whole, but the NA fraction showed unusual ¹⁵N enrichment. However, the percentage of nodule N in this fraction was small. NA fractions from yellow lupin and pea nodules and from soybean leaves were not enriched in ¹⁵N. Nor was the NA fraction in ruptured bacteriods and cortical tissue of soybean nodules. Variation among soybean nodule fractions in the preponderance in protein of different amino acids was not large enough to explain the differences in ¹⁵N abundances among them. A hypothesis, consistent with all known data, concerning the mechanism leading to the observed excess ¹⁵N of lupin and soybean bacteriods is offered.     

Characteristics and transferability of new apple EST-derived SSRs to other Rosaceae species

Genic microsatellites or simple sequence repeat markers derived from expressed sequence tags (ESTs), referred to as EST–SSRs, are inexpensive to develop, represent transcribed genes, and often have assigned putative function. The large apple (Malus × domestica) EST database (over 300,000 sequences) provides a valuable resource for developing well-characterized DNA molecular markers. In this study, we have investigated the level of transferability of 68 apple EST–SSRs in 50 individual members of the Rosaceae family, representing three genera and 14 species. These representatives included pear (Pyrus communis), apricot (Prunus armeniaca), European plum (P. domestica), Japanese plum (P. salicina), almond (P. dulcis), peach (P. persica), sour cherry (P. cerasus), sweet cherry (P. avium), strawberry (Fragaria vesca, F. moschata, F. virginiana, F. nipponica, and F. pentaphylla), and rose (Rosa hybrida). All 68 primer pairs gave an amplification product when tested on eight apple cultivars, and for most, the genomic DNA-derived amplification product matched the expected size based on EST (in silico) data. When tested across members of the Rosaceae, 75% of these primer pairs produced amplification products. Transferability of apple EST–SSRs across the Rosaceae ranged from 25% in apricot to 59% in the closely related pear. Besides pear, the highest transferability of these apple EST–SSRs, at the genus level, was observed for strawberry and peach/almond, 49 and 38%, respectively. Three markers amplified in at least one genotype within all tested species, while eight additional markers amplified in all species, except for cherry. These 11 markers are deemed good candidates for a widely transferable Rosaceae marker set provided their level of polymorphism is adequate. Overall, these findings suggest that transferability of apple EST–SSRs across Rosaceae is varied, yet valuable, thereby providing additional markers for comparative mapping and for carrying out evolutionary studies.     

AFLP analysis of genetic variability in New Guinea impatiens

New Guinea impatiens ( Impatiens hawkeri) is an economically important floral crop, however, little work has been conducted to further our understanding of the genetics of this crop. In this study, we used amplified fragment length polymorphism (AFLP) technology to investigate the level of polymorphism present among 41 commercial cultivars of New Guinea impatiens, study their genetic relatedness, and assess the genetic diversity in this material. An efficient DNA extraction protocol was developed, and a total of 48 EcoRI and MseI primer combinations were used for PCR amplification. Amplification products were then subjected to polyacrylamide gel electrophoresis. The AFLP analysis showed that all 41 cultivars generated between 73 and 130 scoreable polymorphic bands per primer combination. Gower's Genetic Dissimilarity estimates for the entire set of cultivars ranged between 0.940 and 0.488. A dendogram was generated from these dissimilarity data that revealed four groupings among these 41 cultivars. The implications of these results on genotypic variation, genetic relationships, and genetic diversity in New Guinea impatiens will be discussed.     

Age‐related changes in the gut microbiota of wild House Sparrow nestlings

Here, we document the development of the House Sparrow Passer domesticus gut microbiota for the benefit of future ecological and evolutionary studies in this widely used avian system. We collected and inventoried luminal and mucosal samples from the distal guts of nestling House Sparrows between 3 and 12 days of age, and also collected similar samples from adult birds. Luminal bacterial community membership and structure differed significantly between nestlings and adults. The relative abundance of Proteobacteria in the lumen decreased around day 9, whereas the relative abundance of Firmicutes increased, demonstrating age‐related changes in the microbiota of House Sparrows.