Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity

Plant communities can be affected both by arbuscular mycorrhizal fungi (AMF) and hemiparasitic plants. However, little is known about the interactive effects of these two biotic factors on the productivity and diversity of plant communities. To address this question, we set up a greenhouse study in which different AMF inocula and a hemiparasitic plant (Rhinanthus minor) were added to experimental grassland communities in a fully factorial design. In addition, single plants of each species in the grassland community were grown with the same treatments to distinguish direct AMF effects from indirect effects via plant competition. We found that AMF changed plant community structure by influencing the plant species differently. At the community level, AMF decreased the productivity by 15–24%, depending on the particular AMF treatment, mainly because two dominant species, Holcus lanatus and Plantago lanceolata, showed a negative mycorrhizal dependency. Concomitantly, plant diversity increased due to AMF inoculation and was highest in the treatment with a combination of two commercial AM strains. AMF had a positive effect on growth of the hemiparasite, and thereby induced a negative impact of the hemiparasite on host plant biomass which was not found in non-inoculated communities. However, the hemiparasite did not increase plant diversity. Our results highlight the importance of interactions with soil microbes for plant community structure and that these indirect effects can vary among AMF treatments. We conclude that mutualistic interactions with AMF, but not antagonistic interactions with a root hemiparasite, promote plant diversity in this grassland community. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Flower patterns are adapted for detection by bees

We have demonstrated previously that honeybees use brightness vision mediated by green (or L-) receptor to detect targets from a long distance. They detect circular targets having a dim, for the L-receptor, centre and bright surround from a longer distance than targets having bright centre and dim surround. Here we show that a majority of bee-pollinated flowers have a centre that, for the L-receptor, is dim with bright surround, i.e. have patterns that are easy for a bee to detect. Flowers with dim for the L-receptor surrounds tend to be larger than those with bright surrounds, indicating that flowers compensate for the impaired visibility of their patterns by increasing the size of their displays.     

Association of medication with the human plasma N-glycome

Glycosylation is highly variable depending on many environmental factors. Using our fully quantitative high-throughput normal phase hydrophilic interaction liquid chromatography platform we have identified glycosylation changes associated with medication in the plasma N-glycome from three different population cohorts: ORCADES from the Orkney Islands in Scotland and CROATIA-Vis and CROATIA-Korcula from the Croatian islands of Vis and Korcula. Associations between glycosylation and the use of hormones (oral contraceptives, hormone replacement therapy), nonsteroidal anti-inflammatory drugs (aspirin and other NSAIDs), oral steroids (prednisolone) and steroid inhalers (beclomethasone) were investigated. Significant differences associated with usage of oral contraceptives were found with increased core-fucosylated biantennary glycans. Decreases in core-fucosylated biantennary glycans, core-fucosylated triantennary glycans with outer-arm fucose, and high mannosylated glycans were associated with the use of anti-inflammatory drugs. All of the changes in glycosylation were independent of blood group status. In conclusion, hormones and anti-inflammatory medication were associated with changes in glycosylation, possibly as a result of the modulatory effect of these drugs on the inflammatory response. In general, cancer is associated with inflammation, and many glycoproteins in the plasma are acute phase related to the host response. These preliminary data indicate the importance of correcting the levels of glycans used as biomarkers for the effects of medication.     

Mechanistic basis of branch-site selection in filamentous bacteria

Many filamentous organisms, such as fungi, grow by tip-extension and by forming new branches behind the tips. A similar growth mode occurs in filamentous bacteria, including the genus Streptomyces, although here our mechanistic understanding has been very limited. The Streptomyces protein DivIVA is a critical determinant of hyphal growth and localizes in foci at hyphal tips and sites of future branch development. However, how such foci form was previously unknown. Here, we show experimentally that DivIVA focus-formation involves a novel mechanism in which new DivIVA foci break off from existing tip-foci, bypassing the need for initial nucleation or de novo branch-site selection. We develop a mathematical model for DivIVA-dependent growth and branching, involving DivIVA focus-formation by tip-focus splitting, focus growth, and the initiation of new branches at a critical focus size. We quantitatively fit our model to the experimentally-measured tip-to-branch and branch-to-branch length distributions. The model predicts a particular bimodal tip-to-branch distribution results from tip-focus splitting, a prediction we confirm experimentally. Our work provides mechanistic understanding of a novel mode of hyphal growth regulation that may be widely employed.     

Optimized protocol for the isolation of spleen-resident murine neutrophils

Neutrophils are an important cellular component of the innate immune system that provides immediate protection to the host from infection. Neutrophil infiltration into inflamed peripheral tissues during infection is beneficial for immunity through phagocytosis of microbes, the release of antimicrobial factors, and secretion of proinflammatory cytokines. Recent reports further suggest that spleen-infiltrating neutrophils play a role in the adaptive immune response by providing survival signals to B cells. However, neutrophils may have detrimental effects on immunity in inflammatory diseases where their recruitment to lymphoid tissues and activation occur abnormally. To determine the contribution of neutrophils that reside in secondary lymphoid tissues to adaptive immunity, direct evaluation of the functional properties of tissue-resident neutrophils is required. We have developed a modified magnetic bead isolation approach for purifying neutrophils from inflamed spleens of autoimmune-prone mice by negative selection. Using this approach, we yielded neutrophils with greater than 90% purity without compromising cell viability. Equally important, the isolation procedure had little effect on the activation of neutrophils and did not impair phagocytic function. Thus, isolation of spleen-resident neutrophils by this optimized approach could be useful for interrogating the functional role of murine neutrophils in normal and abnormal immune responses. ? 2012 International Society for Advancement of Cytometry.     

The diagnostic challenge of progressive pseudorheumatoid dysplasia (PPRD): a review of clinical features, radiographic features, and WISP3 mutations in 63 affected individuals

Progressive pseudorheumatoid dysplasia (PPRD) is a genetic, non-inflammatory arthropathy caused by recessive loss of function mutations in WISP3 (Wnt1-inducible signaling pathway protein 3; MIM 603400), encoding for a signaling protein. The disease is clinically silent at birth and in infancy. It manifests between the age of 3 and 6 years with joint pain and progressive joint stiffness. Affected children are referred to pediatric rheumatologists and orthopedic surgeons; however, signs of inflammation are absent and anti-inflammatory treatment is of little help. Bony enlargement at the interphalangeal joints progresses leading to camptodactyly. Spine involvement develops in late childhood and adolescence leading to short trunk with thoracolumbar kyphosis. Adult height is usually below the 3rd percentile. Radiographic signs are relatively mild. Platyspondyly develops in late childhood and can be the first clue to the diagnosis. Enlargement of the phalangeal metaphyses develops subtly and is usually recognizable by 10 years. The femoral heads are large and the acetabulum forms a distinct "lip" overriding the femoral head. There is a progressive narrowing of all articular spaces as articular cartilage is lost. Medical management of PPRD remains symptomatic and relies on pain medication. Hip joint replacement surgery in early adulthood is effective in reducing pain and maintaining mobility and can be recommended. Subsequent knee joint replacement is a further option. Mutation analysis of WISP3 allowed the confirmation of the diagnosis in 63 out of 64 typical cases in our series. Intronic mutations in WISP3 leading to splicing aberrations can be detected only in cDNA from fibroblasts and therefore a skin biopsy is indicated when genomic analysis fails to reveal mutations in individuals with otherwise typical signs and symptoms. In spite of the first symptoms appearing in early childhood, the diagnosis of PPRD is most often made only in the second decade and affected children often receive unnecessary anti-inflammatory and immunosuppressive treatments. Increasing awareness of PPRD appears to be essential to allow for a timely diagnosis.     

Aerobic endurance training versus relaxation training in patients with migraine (ARMIG): study protocol for a randomized controlled trial

ABSTRACT: BACKGROUND: Migraine is one of the most frequent headache diseases and impairs patients' quality of life. Up to now, many randomized studies reported efficacy of prophylactic therapy with medications such as beta-blockers or anti-epileptic drugs. Non-medical treatment, like aerobic endurance training, is considered to be an encouraging alternative in migraine prophylaxis. However, there is still a lack of prospective, high-quality randomized trials. We therefore designed a randomized controlled trial to evaluate the efficacy of aerobic endurance training versus relaxation training in patients with migraine (ARMIG). METHODS: This is a single-center, open-label, prospective, randomized trial. Sixty participants with migraine are randomly allocated to either endurance training or a relaxation group. After baseline headache diary documentation over at least 4 weeks, participants in the exercise group will start moderate aerobic endurance training under a sport therapist's supervision at least 3 times a week over a 12-week period. The second group will perform Jacobson's progressive muscle relaxation training guided by a trained relaxation therapist, also at least 3 times a week over a 12-week period. Both study arms will train in groups of up to 10 participants. More frequent individual training is possible. The follow-up period will be 12 weeks after the training period. The general state of health, possible state of anxiety or depression, impairments due to the headache disorder, pain-related disabilities, the headache-specific locus of control, and the motor fitness status are measured with standardized questionnaires. DISCUSSION: The study design is adequate to generate meaningful results. The trial will be helpful in gaining important data on exercise training for non-medical migraine prophylaxis. Trial registration The trial is registered at ClinicalTrials.gov: NCT01407861.     

Two decades of biomonitoring polar bear health in Greenland: a review

Background

Different animal models are used as fracture models in orthopaedic research prior to implant use in humans, although biomechanical forces can differ to a great extend between species due to variable anatomic conditions, particularly with regard to the gait. The rabbit is an often used fracture model, but biomechanical data are very rare. The objective of the present study was to measure axial forces, bending moments, and bending axis directly in the rabbit tibia in vivo. The following hypothesis was tested: Axial forces and bending moments in the mid-diaphysis of rabbit tibia differ from other experimental animals or indirectly calculated data.

Methods

A minifixateur system with 4 force sensors was developed and attached to rabbit tibia (n = 4), which were subsequently ostectomised. Axial forces, bending moments and bending angles were calculated telemetrically during weight bearing in motion between 6 and 42 days post operation.

Results

Highest single values were 201% body weight [% bw] for axial forces and 409% bw cm for bending moments. Whereas there was a continous decrease in axial forces over time after day 10 (P = 0.03 on day 15), a decrease in bending moments was inconsistent (P = 0.03 on day 27). High values for bending moments were frequently, but not consistently, associated with high values for axial forces.

Conclusion

Axial forces in rabbit tibia exceeded axial forces in sheep, and differed from indirectly calculated data. The rabbit is an appropriate fracture model because axial loads and bending moments in rabbit tibia were more closely to human conditions than in sheep tibia as an animal model.     

Genotyping success of historical Eurasian lynx (Lynx lynx L.) samples

Historical samples, like tanned hides and trophy skulls, can be extremely important for genetic studies of endangered or elusive species. Selection of a sampling protocol that is likely to provide sufficient amount and quality of DNA with a minimum damage to the original specimen is often critical for a success of the study. We investigated microsatellite genotyping success of DNA isolated from three different types of Eurasian lynx historical samples. We analysed a total of 20 microsatellite loci in 106 historical samples from the endangered Dinaric lynx population, established from re-introduction of three pairs of lynx in 1973 from Slovakian Carpathians. Of the three tested sample types, turbinal bone and septum from the nasal cavity of the trophy skulls had the lowest percentage of samples successfully genotyped for all 20 microsatellite loci. Footpad samples, collected using a cork drill, exhibited better results in polymerase chain reaction amplification and genotyping than samples of footpad epidermis cut with a scalpel. We report simple and efficient sampling protocols, which could be widely applied for future studies utilizing historical samples.