SciCombinator

Discover the most talked about and latest scientific content & concepts.

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Animals use a variety of escape mechanisms to increase the probability of surviving predatory attacks. Antipredator defenses can be elaborate, making their evolutionary origin unclear. Trap-jaw ants are known for their rapid and powerful predatory mandible strikes, and some species have been observed to direct those strikes at the substrate, thereby launching themselves into the air away from a potential threat. This potential escape mechanism has never been examined in a natural context. We studied the use of mandible-powered jumping in Odontomachus brunneus during their interactions with a common ant predator: pit-building antlions. We observed that while trap-jaw ant workers escaped from antlion pits by running in about half of interactions, in 15% of interactions they escaped by mandible-powered jumping. To test whether escape jumps improved individual survival, we experimentally prevented workers from jumping and measured their escape rate. Workers with unrestrained mandibles escaped from antlion pits significantly more frequently than workers with restrained mandibles. Our results indicate that some trap-jaw ant species can use mandible-powered jumps to escape from common predators. These results also provide a charismatic example of evolutionary co-option, where a trait that evolved for one function (predation) has been co-opted for another (defense).

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Helping behavior is a prosocial behavior whereby an individual helps another irrespective of disadvantages to him or herself. In the present study, we examined whether rats would help distressed, conspecific rats that had been soaked with water. In Experiment 1, rats quickly learned to liberate a soaked cagemate from the water area by opening the door to allow the trapped rat into a safe area. Additional tests showed that the presentation of a distressed cagemate was necessary to induce rapid door-opening behavior. In addition, it was shown that rats dislike soaking and that rats that had previously experienced a soaking were quicker to learn how to help a cagemate than those that had never been soaked. In Experiment 2, the results indicated that rats did not open the door to a cagemate that was not distressed. In Experiment 3, we tested behavior when rats were forced to choose between opening the door to help a distressed cagemate and opening a different door to obtain a food reward. Irrespective of how they learned to open the door, in most test trials, rats chose to help the cagemate before obtaining a food reward, suggesting that the relative value of helping others is greater than the value of a food reward. These results suggest that rats can behave prosocially and that helper rats may be motivated by empathy-like feelings toward their distressed cagemate.

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Globalization describes processes of greater integration of the world economy through increased flows goods, services, capital and people. Globalization has undergone significant transformation since the 1970s, entrenching neoliberal economics as the dominant model of global market integration. Although this transformation has generated some health gains, since the 1990s it has also increased health disparities.

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Endothermy (the metabolic production and retention of heat to warm body temperature above ambient) enhances physiological function, and whole-body endothermy generally sets mammals and birds apart from other animals. Here, we describe a whole-body form of endothermy in a fish, the opah (Lampris guttatus), that produces heat through the constant “flapping” of wing-like pectoral fins and minimizes heat loss through a series of counter-current heat exchangers within its gills. Unlike other fish, opah distribute warmed blood throughout the body, including to the heart, enhancing physiological performance and buffering internal organ function while foraging in the cold, nutrient-rich waters below the ocean thermocline.

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Comprehensiveness is lauded as 1 of the 5 core virtues of primary care, but its relationship with outcomes is unclear. We measured associations between variations in comprehensiveness of practice among family physicians and healthcare utilization and costs for their Medicare beneficiaries.

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Most children do not meet the recommendation for fruit consumption. Apples are the second most commonly consumed fruit in the US; however, no studies have examined the association of total apple products, apples, apple sauce, and 100 % apple juice consumption on diet quality and weight/adiposity in children.

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Members of the family Zingiberaceae including turmeric, ginger, Javanese ginger, and galangal have been used for centuries in traditional medicine. Preclinical studies of Zingiberaceae extracts have shown analgesic properties. This study aims to systematically review and meta-analyze whether extracts from Zingiberaceae are clinically effective hypoalgesic agents.

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GNE myopathy is an autosomal recessive adult-onset disorder characterized by progressive muscle atrophy and weakness, initially involving the distal muscles, while often sparing the quadriceps. It is caused by variants in the GNE gene that encodes a key bifunctional enzyme in the sialic acid biosynthetic pathway. We investigated the clinical and molecular characteristics of 18 non-Jewish Persian patients from 11 unrelated GNE myopathy families. In addition, we reviewed the previously reported cases and suggest genotype-phenotype correlations for the identified variants. Comprehensive clinical and laboratory evaluations were carried out. Sequencing of the GNE gene was performed using genomic DNA from the patients. Screening of the identified variants was performed in all relevant family members. Molecular analyses identified three causative homozygous GNE variants in 11 families: c.2228T>C (p. M743T) in 7, c.830G>A (p.R277Q) in 2, and one novel variation (c.804G>A) in 2 families that results in a synonymous codon change (p.L268=) and likely creates a novel splice site affecting the protein function. This study confirms that c.2228T>C (p.M743T) is the most prevalent disease-causing variant in the non-Jewish Persian population, but other GNE variants can cause GNE myopathy in this population. The patients with all three different variants had similar ages of onset. The youngest patient was an 18-year-old girl in whom the c.830G>A (p.R277Q) variant was identified, whereas the oldest onset age (31 years) was seen in a male patient with c.804G>A (p.L268=). The results of this investigation expand our knowledge about the genotype-phenotype correlations in GNE myopathy and aid in clinical management and therapeutic interventions.European Journal of Human Genetics advance online publication, 13 May 2015; doi:10.1038/ejhg.2015.78.

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In an aging European population, an increasing number of individuals will suffer from gastric cancer in the coming two decades. Recent research has determined the risk for gastric cancer in patients with different stages of gastric atrophy. Based on these data, it is now recommended that surveillance is offered to individuals with advanced stages of atrophic gastritis. Endoscopic biopsies of the gastric antrum and corpus are recommended in order to assess the severity and extent of gastric atrophy. This enables identification of those at highest risk of progressing to cancer. However, systematic reviews have shown that in recent years many researchers have assessed new endoscopic technologies for their accuracy in determining the severity and extent of gastric atrophy and metaplasia without the use of histology. Simple, reliable and accurate endoscopic features have been identified that can be used to either target biopsies or avoid biopsy sampling in the absence of endoscopic features of atrophy and intestinal metaplasia. This may largely simplify everyday practice. Randomized trials or large observational studies are now needed to demonstrate the accuracy of endoscopic assessment of the entire gastric mucosa and its impact on patient management.

22

Benzylisoquinoline alkaloids (BIAs) are a diverse family of plant-specialized metabolites that include the pharmaceuticals codeine and morphine and their derivatives. Microbial synthesis of BIAs holds promise as an alternative to traditional crop-based manufacturing. Here we demonstrate the production of the key BIA intermediate (S)-reticuline from glucose in Saccharomyces cerevisiae. To aid in this effort, we developed an enzyme-coupled biosensor for the upstream intermediate L-3,4-dihydroxyphenylalanine (L-DOPA). Using this sensor, we identified an active tyrosine hydroxylase and improved its L-DOPA yields by 2.8-fold via PCR mutagenesis. Coexpression of DOPA decarboxylase enabled what is to our knowledge the first demonstration of dopamine production from glucose in yeast, with a 7.4-fold improvement in titer obtained for our best mutant enzyme. We extended this pathway to fully reconstitute the seven-enzyme pathway from L-tyrosine to (S)-reticuline. Future work to improve titers and connect these steps with downstream pathway branches, already demonstrated in S. cerevisiae, will enable low-cost production of many high-value BIAs.