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Northern voles and lemmings are famous for their spectacular multiannual population cycles with high amplitudes. Such cyclic vole populations in Scandinavia have shown an unexpected and marked long-term decline in density since the early 1970s, particularly with a marked shift to lower spring densities in the early 1980s. The vole decline, mainly characterized by a strongly decreased rate of change in numbers over winter, is associated with an increased occurrence of mild and wet winters brought about by a recent change in the North Atlantic Oscillation. This has led to a decrease in winter stability and has shortened the period with protective snow cover, the latter considered as an important prerequisite for the occurrence of multiannual, high-amplitude cycles in vole populations. Although the vole decline is predicted to be negative for predators' reproduction and abundance, empirical data showing this are rare. Here we show that the dynamics of a predator-prey system (Tengmalm's owl, Aegolius funereus, and voles), have in recent years gradually changed from 3-4 yr, high-amplitude cycles towards more or less annual fluctuations only.

Purpose The aim was to compare the outcome of anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autograft, with and without a poly(urethane urea) augmentation device. Methods Patients were randomized to BPTB reconstruction with a synthetic degradable augmentation device ( n  = 96) or without augmentation ( n  = 105). Follow-ups were made during 4 years after surgical treatment with the KT1000™ arthrometer for objective evaluation of sagittal stability. The Tegner scoring system for assessment of physical activity level and the Knee injury Osteoarthritis Outcome Score (KOOS) for assessment of knee-specific health were evaluated after 4 and 12 years. Results KT1000™ tests showed a significant decrease in mean manual maximum side-to-side difference after 4 years in both patients with and those without augmentation, without any statistical difference between the groups (n.s.). Pre-injury, 76 and 80 % of the patients, respectively, reported Tegner level 7–10. Pre-surgery, the corresponding figures were 6 and 5 %, and at 4 years, 33 and 30 %. Twelve years after ACL reconstruction, both groups had significantly higher KOOS scores in function in sports and recreational activities ( p  < 0.001) and knee-related quality of life ( p  < 0.001) compared to before surgical treatment. In 10 patients, the augmentation device was removed, in six of these because of insufficient screw fixation to femur and in four due to swelling/hydrops. Conclusion This study showed no significant difference in clinical outcome with use of an additional synthetic augmentation device in a single-bundle BPTB ACL reconstruction compared with non-augmentation, in short, intermediate, or long-term perspective. Level of evidence Therapeutic study, Level I.

Summary 1 In sexually size‐dimorphic birds, the larger sex requires more energy during growth, and often suffers from a higher mortality risk during growth than the smaller one when food is limited. 2 Sex‐specific growth and mortality were examined in Tengmalm's owl Aegolius funereus (L.) nestlings, a species in which adult females are slightly larger than males. Nestlings were unambiguously sexed using molecular techniques. Nestling mortality in broods provided with supplemental food was compared with that in controls in an experiment carried out during two breeding seasons, 1998 and 1999. 3 The natural food supply during the two years of the experiment differed. Although the spring vole abundance was similar for the two years, 1998 was characterized by a less severe decline in vole abundance during the previous winter, and also a greater increase in vole abundance during the summer than 1999. It was consequently inferred that the owls’ natural food supply was more limited in 1999. 4 In 1998, female nestlings attained a 5% higher asymptotic mass than males, and fed nestlings were heavier than controls. No difference in rate of mass gain or wing growth was detected. 5 Overall mortality was lower in fed broods than controls in 1999 only. Unexpectedly, female nestling mortality was unaffected by supplemental feeding during both years. However, in 1999, when natural food supply was more limited, male nestling mortality was reduced in supplementary‐fed broods. 6 It is suggested that the females’ larger size gives them a competitive advantage against their male siblings when fighting over food items, and that when food is limited, males rather than females suffer increased mortality owing to lack of food. 7 This study illustrates the importance of repeating food supplementation experiments to account for annual variation in natural food supply.

1. In sexually size-dimorphic birds, the larger sex requires more energy during growth, and often suffers from a higher mortality risk during growth than the smaller one when food is limited. 2. Sex-specific growth and mortality were examined in Tengmalm's owl Aegolius funereus (L.) nestlings, a species in which adult females are slightly larger than males. Nestlings were unambiguously sexed using molecular techniques. Nestling mortality in broods provided with supplemental food was compared with that in controls in an experiment carried out during two breeding seasons, 1998 and 1999. 3. The natural food supply during the two years of the experiment differed. Although the spring vole abundance was similar for the two years, 1998 was characterized by a less severe decline in vole abundance during the previous winter, and also a greater increase in vole abundance during the summer than 1999. It was consequently inferred that the owls' natural food supply was more limited in 1999. 4. In 1998, female nestlings attained a 5% higher asymptotic mass than males, and fed nestlings were heavier than controls. No difference in rate of mass gain or wing growth was detected. 5. Overall mortality was lower in fed broods than controls in 1999 only. Unexpectedly, female nestling mortality was unaffected by supplemental feeding during both years. However, in 1999, when natural food supply was more limited, male nestling mortality was reduced in supplementary-fed broods. 6. It is suggested that the females' larger size gives them a competitive advantage against their male siblings when fighting over food items, and that when food is limited, males rather than females suffer increased mortality owing to lack of food. 7. This study illustrates the importance of repeating food supplementation experiments to account for annual variation in natural food supply.

We studied the abundance and diversity of six species of small mammals in relation to structural habitat factors related to the vegetation in a mountain region in northern Sweden. Small mammals were snap-trapped along transects at different altitudes in subarctic birch and coniferous forest. Three structural habitat factors, the cover of logs (coarse woody debris), branches (fine woody debris) and umbrella vegetation (vegetation higher than 30 cm) were estimated for each trapping site. Initially, the data set was analyzed by principal component analysis. The first extracted component, which could be interpreted as a variable of overall abundance of the small mammals, explained 93% of all variance in the species-environment relation. This component was positively correlated with the cover of logs, but not with the cover of branches and umbrella vegetation. On the species level, the abundance of Clethrionomys glareolus, C. rufocanus and Myopus schisticolor showed positive correlations with both cover of logs and umbrella vegetation. In contrast, the abundance of Lemmus lemmus was negatively correlated to the cover of logs. There was also a positive correlation of the abundance of C. glareolus and M. schisticolor with the cover of branches. Furthermore, the populations of C. glareolus tended to be more numerically stable where more logs were present. Our study stresses the importance of structural habitat factors in affecting the overall abundance and diversity of small mammal assemblages in the subarctic birch and taiga landscape. Most likely, the positive relations of species abundance and diversity with the structural factors were closely linked to a general effect on habitat conditions for the small mammals, such as the amount of shelter and food.

Human gut microbiota produce a variety of molecules, some of which enter the bloodstream and impact health. Conversely, dietary or pharmacological compounds may affect the microbiota before entering the circulation. Characterization of these interactions is an important step towards understanding the effects of the gut microbiota on health. In this cross-sectional study, we used deep metagenomic sequencing and ultra-high-performance liquid chromatography linked to mass spectrometry for a detailed characterization of the gut microbiota and plasma metabolome, respectively, of 8583 participants invited at age 50 to 64 from the population-based Swedish CArdioPulmonary bioImage Study. Here, we find that the gut microbiota explain up to 46% of the variance of individual plasma metabolites and we present 997 associations between alpha diversity and plasma metabolites and 546,819 associations between specific gut metagenomic species and plasma metabolites in an online atlas ( https://gutsyatlas.serve.scilifelab.se/ ). We exemplify the potential of this resource by presenting novel associations between dietary factors and oral medication with the gut microbiome, and microbial species strongly associated with the uremic toxin p -cresol sulfate. This resource can be used as the basis for targeted studies of perturbation of specific metabolites and for identification of candidate plasma biomarkers of gut microbiota composition. Here, Dekkers et al. characterize associations of 1528 gut metagenomic species with the plasma metabolome in 8583 participants of the SCAPIS Study, and find that gut microbiota explain up to 58% of the variance of individual plasma metabolites.

The plant hormone auxin (indole-3-acetic acid [IAA]) has previously been suggested to regulate diverse forms of dormancy in both seed plants and liverworts. Here, we use loss- and gain-of-function alleles for auxin synthesis- and signaling-related genes, as well as pharmacological approaches, to study how auxin regulates development and dormancy in the gametophyte generation of the liverwort Marchantia polymorpha. We found that M. polymorpha possess the smallest known toolkit for the indole-3-pyruvic acid (IPyA) pathway in any land plant and that this auxin synthesis pathway mainly is active in meristematic regions of the thallus. Previously a Trp-independent auxin synthesis pathway has been suggested to produce a majority of IAA in bryophytes. Our results indicate that the Trp-dependent IPyA pathway produces IAA that is essential for proper development of the gametophyte thallus of M. polymorpha. Furthermore, we show that dormancy of gemmae is positively regulated by auxin synthesized by the IPyA pathway in the apex of the thallus. Our results indicate that auxin synthesis, transport, and signaling, in addition to its role in growth and development, have a critical role in regulation of gemmae dormancy in M. polymorpha.

The circadian clock coordinates an organism’s growth, development and physiology with environmental factors. One illuminating example is the rhythmic growth of hypocotyls and cotyledons in Arabidopsis thaliana . Such daily oscillations in leaf position are often referred to as sleep movements or nyctinasty. Here, we report that plantlets of the liverwort Marchantia polymorpha show analogous rhythmic movements of thallus lobes, and that the circadian clock controls this rhythm, with auxin a likely output pathway affecting these movements. The mechanisms of this circadian clock are partly conserved as compared to angiosperms, with homologs to the core clock genes PRR , RVE and TOC1 forming a core transcriptional feedback loop also in M. polymorpha .

Previous studies in the liverwort Marchantia polymorpha have shown that the putative evening complex (EC) genes LUX ARRHYTHMO ( LUX ) and ELF4-LIKE ( EFL ) have a function in the liverwort circadian clock. Here, we studied the growth phenotypes of Mp LUX and Mp EFL loss-of-function mutants, to establish if PHYTOCHROME-INTERACTING FACTOR ( PIF ) and auxin act downstream of the M . polymorpha EC in a growth-related pathway similar to the one described for the flowering plant Arabidopsis. We examined growth rates and cell properties of loss-of-function mutants, analyzed protein-protein interactions and performed gene expression studies using reporter genes. Obtained data indicate that an EC can form in M . polymorpha and that this EC regulates growth of the thallus. Altered auxin levels in Mp lux mutants could explain some of the phenotypes related to an increased thallus surface area. However, because Mp PIF is not regulated by the EC, and because Mp pif mutants do not show reduced growth, the growth phenotype of EC-mutants is likely not mediated via Mp PIF . In Arabidopsis, the circadian clock regulates elongation growth via PIF and auxin, but this is likely not an evolutionarily conserved growth mechanism in land plants. Previous inventories of orthologs to Arabidopsis clock genes in various plant lineages showed that there is high levels of structural differences between clocks of different plant lineages. Here, we conclude that there is also variation in the output pathways used by the different plant clocks to control growth and development.

While angiosperm clocks can be described as an intricate network of interlocked transcriptional feedback loops, clocks of green algae have been modelled as a loop of only two genes. To investigate the transition from a simple clock in algae to a complex one in angiosperms, we performed an inventory of circadian clock genes in bryophytes and charophytes. Additionally, we performed functional characterization of putative core clock genes in the liverwort Marchantia polymorpha and the hornwort Anthoceros agrestis. Phylogenetic construction was combined with studies of spatiotemporal expression patterns and analysis of M. polymorpha clock gene mutants. Homologues to core clock genes identified in Arabidopsis were found not only in bryophytes but also in charophytes, albeit in fewer copies. Circadian rhythms were detected for most identified genes in M. polymorpha and A. agrestis, and mutant analysis supports a role for putative clock genes in M. polymorpha. Our data are in line with a recent hypothesis that adaptation to terrestrial life occurred earlier than previously expected in the evolutionary history of charophyte algae. Both gene duplication and acquisition of new genes was important in the evolution of the plant circadian clock, but gene loss has also contributed to shaping the clock of bryophytes.