Outbreaking forest insect drives phase synchrony among sympatric folivores: Exploring potential mechanisms

We explore a common feature of insect population dynamics, interspecific synchrony, which refers to synchrony in population dynamics among sympatric populations of different species. Such synchrony can arise via several possible mechanisms, including shared environmental effects and shared trophic interactions, but distinguishing the relative importance among different mechanisms can be challenging. We analyze interannual time series of population densities of the larch budmoth, Zeiraphera griseana (Lepidoptera: Tortricidae), along with six sympatric larch-feeding folivores from a site in the European Alps 1952–1979. These species include five lepidopterans, Exapate duratella, Ptycholomoides aeriferana, Spilonota laricana, Epirrita autumnata and Teleiodes saltuum, and one hymenopteran sawfly Pristiphora laricis. We document that the highly regular oscillatory behavior (period 9–10 years) of Z. griseana populations is similarly evident in the dynamics of most of the sympatric folivores. We also find that all of the sympatric species are phase synchronized with Z. griseana populations with half of the sympatric species exhibiting nonlagged phase synchrony and three of the species exhibiting 2–5 year lags behind Z. griseana populations. We adapt a previously developed tritrophic model of Z. griseana dynamics to explore possible mechanisms responsible for observed phase synchronization. Results suggest that either shared stochastic influences (e.g., weather) or shared parasitoid impacts are likely causes of nonlagged phase synchronization. The model further indicates that observed patterns of lagged phase synchronization are most likely caused by either shared delayed induced host plant defenses or direct density-dependent effects shared with Z. griseana.     

Mutations in BICD2, which Encodes a Golgin and Important Motor Adaptor,Cause Congenital Autosomal-Dominant Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a heterogeneous group of neuromuscular disorders caused by degeneration of lower motor neurons. Although functional loss of SMN1 is associated with autosomal-recessive childhood SMA, the genetic cause for most families affected by dominantly inherited SMA is unknown. Here, we identified pathogenic variants in bicaudal D homolog 2 (Drosophila) (BICD2) in three families afflicted with autosomal-dominant SMA. Affected individuals displayed congenital slowly progressive muscle weakness mainly of the lower limbs and congenital contractures. In a large Dutch family, linkage analysis identified a 9q22.3 locus in which exome sequencing uncovered c.320C>T (p.Ser107Leu) in BICD2. Sequencing of 23 additional families affected by dominant SMA led to the identification of pathogenic variants in one family from Canada (c.2108C>T [p.Thr703Met]) and one from the Netherlands (c.563A>C [p.Asn188Thr]). BICD2 is a golgin and motor-adaptor protein involved in Golgi dynamics and vesicular and mRNA transport. Transient transfection of HeLa cells with all three mutant BICD2 cDNAs caused massive Golgi fragmentation. This observation was even more prominent in primary fibroblasts from an individual harboring c.2108C>T (p.Thr703Met) (affecting the C-terminal coiled-coil domain) and slightly less evident in individuals with c.563A>C (p.Asn188Thr) (affecting the N-terminal coiled-coil domain). Furthermore, BICD2 levels were reduced in affected individuals and trapped within the fragmented Golgi. Previous studies have shown that Drosophila mutant BicD causes reduced larvae locomotion by impaired clathrin-mediated synaptic endocytosis in neuromuscular junctions. These data emphasize the relevance of BICD2 in synaptic-vesicle recycling and support the conclusion that BICD2 mutations cause congenital slowly progressive dominant SMA.     

The effect of multiple natural enemies on a shared herbivore prey

相似文献   

Detection of in vivo protein-DNA interactions using DamID in mammalian cells

Understanding gene regulatory networks in mammalian cells requires detailed knowledge of protein-DNA interactions. Commonly used methods for genome-wide mapping of these interactions are based on chromatin immunoprecipitation. However, these methods have some drawbacks, such as the use of crosslinking reagents, the need for highly specific antibodies and relatively large amounts of starting material. We present DamID, an alternative technique to map genome-wide occupancy of interaction sites in vivo, that bypasses these limitations. DamID is based on the expression of a fusion protein consisting of a protein of interest and DNA adenine methyltransferase (Dam). This leads to methylation of adenines near sites where the protein of interest interacts with the DNA. These methylated sequences are subsequently amplified by a methylation-specific PCR protocol and identified by hybridization to microarrays. Using DamID, genome-wide maps of the binding of DNA-interacting proteins in mammalian cells can be constructed efficiently. Depending on the strategy used for expression of the Dam-fusion proteins, genome-wide binding maps can be obtained in as little as 2 weeks.     

Risk Assessment for Key Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem Under Combined Ocean Acidification and Warming

Ecosystems - The Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of these processes in comparison with global...     

Universal activity-based labeling method for ammonia- and alkane-oxidizing bacteria

The advance of metagenomics in combination with intricate cultivation approaches has facilitated the discovery of novel ammonia-, methane-, and other short-chain alkane-oxidizing microorganisms, indicating that our understanding of the microbial biodiversity within the biogeochemical nitrogen and carbon cycles still is incomplete. The in situ detection and phylogenetic identification of novel ammonia- and alkane-oxidizing bacteria remain challenging due to their naturally low abundances and difficulties in obtaining new isolates from complex samples. Here, we describe an activity-based protein profiling protocol allowing cultivation-independent unveiling of ammonia- and alkane-oxidizing bacteria. In this protocol, 1,7-octadiyne is used as a bifunctional enzyme probe that, in combination with a highly specific alkyne-azide cycloaddition reaction, enables the fluorescent or biotin labeling of cells harboring active ammonia and alkane monooxygenases. Biotinylation of these enzymes in combination with immunogold labeling revealed the subcellular localization of the tagged proteins, which corroborated expected enzyme targets in model strains. In addition, fluorescent labeling of cells harboring active ammonia or alkane monooxygenases provided a direct link of these functional lifestyles to phylogenetic identification when combined with fluorescence in situ hybridization. Furthermore, we show that this activity-based labeling protocol can be successfully coupled with fluorescence-activated cell sorting for the enrichment of nitrifiers and alkane-oxidizing bacteria from complex environmental samples, enabling the recovery of high-quality metagenome-assembled genomes. In conclusion, this study demonstrates a novel, functional tagging technique for the reliable detection, identification, and enrichment of ammonia- and alkane-oxidizing bacteria present in complex microbial communities.Subject terms: Environmental microbiology, Sequencing, Microbiology     

Mass spectrometry-assisted study reveals that lysine residues 1967 and 1968 have opposite contribution to stability of activated factor VIII

The A2 domain rapidly dissociates from activated factor VIII (FVIIIa) resulting in a dampening of the activity of the activated factor X-generating complex. The amino acid residues that affect A2 domain dissociation are therefore critical for FVIII cofactor function. We have now employed chemical footprinting in conjunction with mass spectrometry to identify lysine residues that contribute to the stability of activated FVIII. We hypothesized that lysine residues, which are buried in FVIII and surface-exposed in dissociated activated FVIII (dis-FVIIIa), may contribute to interdomain interactions. Mass spectrometry analysis revealed that residues Lys(1967) and Lys(1968) of region Thr(1964)-Tyr(1971) are buried in FVIII and exposed to the surface in dis-FVIIIa. This result, combined with the observation that the FVIII variant K1967I is associated with hemophilia A, suggests that these residues contribute to the stability of activated FVIII. Kinetic analysis revealed that the FVIII variants K1967A and K1967I exhibit an almost normal cofactor activity. However, these variants also showed an increased loss in cofactor activity over time compared with that of FVIII WT. Remarkably, the cofactor activity of a K1968A variant was enhanced and sustained for a prolonged time relative to that of FVIII WT. Surface plasmon resonance analysis demonstrated that A2 domain dissociation from activated FVIII was reduced for K1968A and enhanced for K1967A. In conclusion, mass spectrometry analysis combined with site-directed mutagenesis studies revealed that the lysine couple Lys(1967)-Lys(1968) within region Thr(1964)-Tyr(1971) has an opposite contribution to the stability of FVIIIa.