Foraging efficiency and size matching in a plant-pollinator community: the importance of sugar content and tongue length.

A long-standing question in ecology is how species interactions are structured within communities. Although evolutionary theory predicts close size matching between floral nectar tube depth and pollinator proboscis length of interacting species, such size matching has seldom been shown and explained in multispecies assemblages. Here, we investigated the degree of size matching among Asteraceae and their pollinators and its relationship with foraging efficiency. The majority of pollinators, especially Hymenoptera, choose plant species on which they had high foraging efficiencies. When proboscides were shorter than nectar tubes, foraging efficiency rapidly decreased because of increased handling time. When proboscides were longer than nectar tubes, a decreased nectar reward rather than an increased handling time made shallow flowers more inefficient to visit. Altogether, this led to close size matching. Overall, our results show the importance of nectar reward and handling time as drivers of plant-pollinator network structure.

Assessing changes in arthropod predator-prey interactions through DNA-based gut content analysis-variable environment, stable diet.

Analysing the structure and dynamics of biotic interaction networks and the processes shaping them is currently one of the key fields in ecology. In this paper, we develop a novel approach to gut content analysis, thereby deriving a new perspective on community interactions and their responses to environment. For this, we use an elevational gradient in the High Arctic, asking how the environment and species traits interact in shaping predator-prey interactions involving the wolf spider Pardosa glacialis. To characterize the community of potential prey available to this predator, we used pitfall trapping and vacuum sampling. To characterize the prey actually consumed, we applied molecular gut content analysis. Using joint species distribution models, we found elevation and vegetation mass to explain the most variance in the composition of the prey community locally available. However, such environmental variables had only a small effect on the prey community found in the spider's gut. These observations indicate that Pardosa exerts selective feeding on particular taxa irrespective of environmental constraints. By directly modelling the probability of predation based on gut content data, we found that neither trait matching in terms of predator and prey body size nor phylogenetic or environmental constraints modified interaction probability. Our results indicate that taxonomic identity may be more important for predator-prey interactions than environmental constraints or prey traits. The impact of environmental change on predator-prey interactions thus appears to be indirect and mediated by its imprint on the community of available prey.

Prevalence of potential drug interactions in Thai patients receiving simvastatin: The causality assessment of musculoskeletal adverse events induced by statin interaction.

Drug-drug interactions are one of the major risk factors associated with statin-induced myopathy. Although simvastatin is widely used in Thailand, studies investigating the prevalence of potential simvastatin-drug interactions (SDIs) and its clinical relevance in Thai population are still limited. We aimed to investigate the prevalence of potential SDIs (phase 1 study) and musculoskeletal adverse effects (AEs) associated with those interactions (phase 2 study). A phase 1 study was retrospectively conducted with outpatients at a 60-bed hospital who received simvastatin between July 1, 2012 and June 30, 2013. In phase 2, study was cross-sectionally conducted in outpatients whose prescriptions contain potential SDIs. Musculoskeletal AEs were evaluated by using symptom checklist questionnaires and measuring plasma creatinine kinase (CK). The causal relationship between the AEs and the potential SDIs was assessed using a Drug Interaction Probability Scale. Out of 3447 simvastatin users, potential SDIs were found in 314 patients (9.1%). The prevalence of prescriptions containing potential SDIs was in the range of 4.7-6.0%. Two-thirds of the potential SDIs were rated to be highly significant while more than 70% were in contraindication list. The most common precipitant drugs were gemfibrozil (382 prescriptions), colchicine (171 prescriptions) and amlodipine (152 prescriptions). Of 49 patients recruited into phase 2 study, we found that 31 patients (63.3%) had myopathy. Myalgia was the most frequently identified AEs (n = 18, 58.1%), followed by asymptomatic rising CK (n = 8, 25.8%), and myositis (n = 5, 16.1%). Musculoskeletal AEs associated with SDIs were found in 16 patients (51.6%). Of these, we found 50.0%, 31.3% and 18.8% had asymptomatic rising CK, myalgia, and myositis, respectively. Precipitant drugs associated with myopathy were amlodipine (2 possible cases), colchicine (3 possible cases), gemfibrozil (8 possible and 1 probable cases), nevirapine (1 possible case), and nicotinic acid (1 possible case). Potential SDIs have been found in the Thai population with a prevalence that is consistent with previous reports. Half of the musculoskeletal AEs identified were associated with SDIs. Systematic screening and management with interdisciplinary co-operation are needed to increase awareness of potential SDIs.

Drug interactions between ALK inhibitors and warfarin with concurrent use of bucolome: a case report.

BACKGROUND: Alectinib, crizotinib, and ceritinib, are anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) that exhibit high protein binding, and their metabolism is associated with the cytochrome P450 (CYP) isoenzymes 2C9 or 3A4. The plasma protein binding rate of warfarin, which is used to prevent and treat venous thromboembolism, is also high. Warfarin is a racemate of S-warfarin and R-warfarin, which are metabolized by CYP2C9 and CYP3A4, respectively. Reports on the drug interactions between each of the above-mentioned ALK-TKIs and warfarin with concurrent use of bucolome are currently lacking. CASE PRESENTATION: We report a case of a patient receiving warfarin and bucolome, whose international normalized ratio (INR) increased after sequential treatment with alectinib, crizotinib, and ceritinib. The patient was a 61-year-old man with a history of aortic valve regurgitation, who was receiving warfarin treatment following aortic valve replacement. Bucolome, which can enhance the effect of warfarin, was also used simultaneously. The patient was diagnosed with primary lung adenocarcinoma, and ALK rearrangement was detected during second-line chemotherapy. After progression of the disease with chemotherapy, sequential treatment with alectinib, crizotinib, and ceritinib was initiated. Pretreatment INR values were in the therapeutic range (target INR of 2-3) but increased to supratherapeutic levels each time after initiation of alectinib, crizotinib, or ceritinib treatment. Adjustment of warfarin dose or discontinuation of bucolome were necessary to maintain the therapeutic INR range. There were no serious bleeding events or substantial changes in dietary intake. Displacement of plasma protein binding or competitive inhibition of metabolism by alectinib, crizotinib, and ceritinib could increase the plasma concentration of the unbound form of warfarin, resulting in high INR values. In addition, alectinib, crizotinib, and ceritinib might cause displacement of bucolome from plasma proteins, followed by displacement of warfarin or inhibition of warfarin metabolism caused by the unbound form of bucolome. CONCLUSIONS: Close monitoring of INR and adjustment of warfarin dosage are needed during treatment with alectinib, crizotinib, or ceritinib in patients who receive warfarin with concurrent use of bucolome.

Size-matching as an important driver of plant-pollinator interactions.

One of the greatest challenges in ecology is to understand and predict the functional outcome of interaction networks. Size-matching between plants and pollinators is one of the key functional traits expected to play a major role in structuring plant-pollinator interactions. However, the community-wide patterns of size-matching remain largely unexplored. We studied the association between the degree of size-matching and foraging efficiency, pollination efficiency and the probability of pairwise interactions in a community of Lamiaceae. Our study revealed that foraging efficiency is maximal when bee proboscis length corresponds to the corolla tube depth of the flower visited. Pollination efficiency was maximal when the bee body height corresponds to the corolla width of the flower visited. While the degree of size-matching did not influence the probability of interaction, it significantly influenced the strength of the interaction in terms of visitation frequency. We suggest a size-matching index as a reliable metric to predict the frequency of interactions as well as the effectiveness of visits in terms of foraging efficiency and pollination efficiency.

Changes in stream food-web structure across a gradient of acid mine drainage increase local community stability.

Understanding what makes food webs stable has long been a goal of ecologists. Topological structure and the distribution and magnitude of interaction strengths in food webs have been shown to confer important stabilizing properties. However, our understanding of how variable species interactions affect food-web structure and stability is still in its infancy. Anthropogenic stress, such as acid mine drainage, is likely to place severe limitations on the food-web structures availabe, due to changes in community composition and body mass distributions. Here, we used mechanistic models to infer food-web structure and quantify stability in streams across a gradient of acid mine drainage. Multiple food webs were iterated for each community based on species pairwise interaction probabilities, in order to incorporate the variability of realistic food-web structure. We found that food-web structure was altered systematically with a 32-fold decrease in the number of links and a twofold increase in connectance across the gradient. Stability generally increased sixfold with increasing acid mine drainage stress, regardless of how interaction strengths were estimated. However, the distribution of the stability measure, s, for some impacted communities separated into clusters of higher and lower magnitude depending on how interaction strengths were estimated. Management and restoration of impacted sites needs to consider their increased stability, as this may have important implications for the recolonization of desirable species. Furthermore, active species introductions may be required to overcome the internal ecological inertia of affected communities.

Drug-drug Interaction-related Uncontrolled Glycemia.

CONTEXT: The literature of drug-drug interaction (DDI)-related uncontrolled causality, and preventability of DDI-induced UCG (HbA1c >7%) in outpatients glycemia (UCG) among outpatients with Type 2 diabetes mellitus is still limited. AIMS: The aim of this study is to identify the prevalence, mechanism, severity, with Type 2 diabetes. SETTINGS AND DESIGN: A cross-sectional study was conducted in Penang General Hospital. METHODS: A computerized system for DDI checking was used to assess the severity and mechanism of DDIs. Drug interaction probability scale was used to evaluate the likelihood of DDIs. Preventability of DDIs has been determined by the instrument of Hallas. The UCG prevalence related to DDIs was further assessed. STATISTICAL ANALYSIS USED: SPSS 21.00 was used in this study. RESULTS: From 425 outpatients with HbA1c% test, their mean age was 58.7 ± 12.8 years. Only 225 (52.9%) cases had controlled glycemia while 200 (47.1%) cases with UCG. They had multiple comorbidities, with a mean number of 3.8 ± 2.2/patient and often prescribed with multiple medications, with a mean number of 6.33 ± 4.67/patient. It has been detected that 86 DDIs causing UCG in 46 patients (23%) with range of (1 - 4) DDIs per patient. Drugs with DDI-induced UCG were as follows: diuretics (79%), salbutamol (9.2%), cortisones (5.8%), and others (6%). The majority of these DDIs were categorized as possible (77.9%) and preventable (37%). CONCLUSION: Nearly one-quarter of UCG was induced by DDIs; most of these DDIs are possible, and more than one-third are preventable. It was concluded that thiazide diuretics have the highest prevalence of DDI-related UCG.

Computing interaction probabilities in signaling networks.

Biological networks inherently have uncertain topologies. This arises from many factors. For instance, interactions between molecules may or may not take place under varying conditions. Genetic or epigenetic mutations may also alter biological processes like transcription or translation. This uncertainty is often modeled by associating each interaction with a probability value. Studying biological networks under this probabilistic model has already been shown to yield accurate and insightful analysis of interaction data. However, the problem of assigning accurate probability values to interactions remains unresolved. In this paper, we present a novel method for computing interaction probabilities in signaling networks based on transcription levels of genes. The transcription levels define the signal reachability probability between membrane receptors and transcription factors. Our method computes the interaction probabilities that minimize the gap between the observed and the computed signal reachability probabilities. We evaluate our method on four signaling networks from the Kyoto Encyclopedia of Genes and Genomes (KEGG). For each network, we compute its edge probabilities using the gene expression profiles for seven major leukemia subtypes. We use these values to analyze how the stress induced by different leukemia subtypes affects signaling interactions.