Developmental biomechanics and age polyethism in leaf-cutter ants.

Many social insects display age polyethism: young workers stay inside the nest, and only older workers forage. This behavioural transition is accompanied by genetic and physiological changes, but the mechanistic origin of it remains unclear. To investigate if the mechanical demands on the musculoskeletal system effectively prevent young workers from foraging, we studied the biomechanical development of the bite apparatus in Atta vollenweideri leaf-cutter ants. Fully matured foragers generated peak in vivo bite forces of around 100 mN, more than one order of magnitude in excess of those measured for freshly eclosed callows of the same size. This change in bite force was accompanied by a sixfold increase in the volume of the mandible closer muscle, and by a substantial increase of the flexural rigidity of the head capsule, driven by a significant increase in both average thickness and indentation modulus of the head capsule cuticle. Consequently, callows lack the muscle force capacity required for leaf-cutting, and their head capsule is so compliant that large muscle forces would be likely to cause damaging deformations. On the basis of these results, we speculate that continued biomechanical development post eclosion may be a key factor underlying age polyethism, wherever foraging is associated with substantial mechanical demands

Proton nuclear magnetic resonance spectroscopic detection of oligomannosidic n glycans in alpha-mannosidosis: a method of monitoring treatment

In Alpha-mannosidosis (MIM 248500) the patients accumulate mainly unbranched oligosaccharide chains in the lysosomes in all body tissues, including the brain. With ensuing therapeutic modalities in man (BMT and ERT) non-invasive methods of monitoring the effect of treatment are needed. Paramount is the possible effect of the treatment on the brain, since this organ is regarded as difficult to reach because of the blood-brain barrier. We therefore performed proton nuclear magnetic resonance spectroscopy (MRS) of the brain in two untreated patients, and a 16-year-old patient treated with BMT at the age of 10 to assess whether this non-invasive method could be applied in the monitoring of the accumulation of abnormal chemicals in the brain of patients. We found an abnormal peak that was not present in the treated patient. A similar pattern was also found in MRS of urine from patients, reflecting the concentration of oligosaccharides in serum and tissues. We therefore conclude that MRS can be a useful method to monitor the effect of treatment for Alpha-Mannosidosis

The evaluation of animal bite treatment centers in the Philippines from a patient perspective

BACKGROUND: The Philippines has built an extensive decentralised network of Animal Bite Treatment Centers (ABTCs) to help bite victims receive timely rabies post-exposure prophylaxis (PEP) at little cost. This study surveyed patients in the community and at ABTCs of three provinces to assess animal bite/scratch incidence, health-seeking behaviour and PEP-related out-of pocket expenses (OOPE). METHODOLOGY AND PRINCIPAL FINDINGS: During community surveys in 90 barangays (neighbourhoods), 53% of households reported at least one animal bite /scratch injury over the past 3 years, similar across urban and rural barangays. Overall bite/scratch incidences in 2016-17 were 67.3, 41.9 and 48.8 per 1,000 population per year for Nueva Vizcaya, Palawan and Tarlac respectively. Incidences were around 50% higher amongst those under 15 years of age, compared to -those older than 15. Household awareness of the nearest ABTCs was generally over 80%, but only 44.9% sought proper medical treatment and traditional remedies were still frequently used. The proportion of patients seeking PEP was not related to the distance or travel time to the nearest ABTC. For those that did not seek medical treatment, most cited a lack of awareness or insufficient funds and almost a third visited a traditional healer. No deaths from bite/scratch injuries were reported. A cohort of 1,105 patients were interviewed at six ABTCs in early 2017. OOPE varied across the ABTCs, from 5.53 USD to 37.83 USD per patient, primarily dependent on the need to pay for immunization if government supplies had run out. Overall, 78% of patients completed the recommended course, and the main reason for non-completion was a lack of time, followed by insufficient funds. Dog observation data revealed that 85% of patients were not truly exposed to rabies, and education in bite prevention might reduce provoked bites and demand for PEP. An accompanying paper details the ABTC network from the health provider's perspective.S1 Checklist. STROBE checklist. https://doi.org/10.1371/journal.pone.0200873.s001S1 Fig. Locations of ABTCs in (A) Nueva Vizcaya, (B) Palawan, and (C) Tarlac. https://doi.org/10.1371/journal.pone.0200873.s002S1 Table. Number of animal bites and scratches recorded by community surveys by province and by year. https://doi.org/10.1371/journal.pone.0200873.s003S2 Table. Additional reasons given in the community survey for not seeking medical treatment for wounds. https://doi.org/10.1371/journal.pone.0200873.s004S3 Table. Reasons for patients not completing the PEP series. https://doi.org/10.1371/journal.pone.0200873.s005S4 Table. Total Out-of-Pocket Expenses, ABTC patient survey, 2017. https://doi.org/10.1371/journal.pone.0200873.s006S5 Table. Biting animal status at day 28 follow-up. https://doi.org/10.1371/journal.pone.0200873.s007S6 Table. PEP completion status of patients bitten by animals that died or were of unknown status. https://doi.org/10.1371/journal.pone.0200873.s008GlaxoSmithKline Biologicals SA (Belgium)http://www.plosone.orgVeterinary Tropical Disease

Asset or Liability: Transnational Links and Political Participation of Foreign-Born Citizens in Taiwan

Viewed as outsiders clinging onto links with their country of origin, immigrants do not often feature positively in electoral politics in their host society. Challenging this conventional view, this paper examines how immigrants make use of their transnational ties to foster their political participation in the host state. This exploration is conducted through our study of the political participation of Vietnamese and Chinese immigrants in Taiwan. Our research finds that transnational ties are politicised by the mainstream political parties. However, such politicisation does not necessarily restrict immigrants’ agency and their socio-political space for political participation. Their transnational ties constitute a dynamic socio-political field in which these maintained connections are acted upon and give rise to a variety of strategies for responding to issues affecting their interests

Interaction Pattern of Arg 62 in the A-Pocket of Differentially Disease-Associated HLA-B27 Subtypes Suggests Distinct TCR Binding Modes

The single amino acid replacement Asp116His distinguishes the two subtypes HLA-B*2705 and HLA-B*2709 which are, respectively, associated and non-associated with Ankylosing Spondylitis, an autoimmune chronic inflammatory disease. The reason for this differential association is so far poorly understood and might be related to subtype-specific HLA:peptide conformations as well as to subtype/peptide-dependent dynamical properties on the nanoscale. Here, we combine functional experiments with extensive molecular dynamics simulations to investigate the molecular dynamics and function of the conserved Arg62 of the α1-helix for both B27 subtypes in complex with the self-peptides pVIPR (RRKWRRWHL) and TIS (RRLPIFSRL), and the viral peptides pLMP2 (RRRWRRLTV) and NPflu (SRYWAIRTR). Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding. This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells. Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype

Leptospirosis in the Asia Pacific region

<p>Abstract</p> <p>Background</p> <p>Leptospirosis is a worldwide zoonotic infection that has been recognized for decades, but the problem of the disease has not been fully addressed, particularly in resource-poor, developing countries, where the major burden of the disease occurs. This paper presents an overview of the current situation of leptospirosis in the region. It describes the current trends in the epidemiology of leptospirosis, the existing surveillance systems, and presents the existing prevention and control programs in the Asia Pacific region.</p> <p>Methods</p> <p>Data on leptospirosis in each member country were sought from official national organizations, international public health organizations, online articles and the scientific literature. Papers were reviewed and relevant data were extracted.</p> <p>Results</p> <p>Leptospirosis is highly prevalent in the Asia Pacific region. Infections in developed countries arise mainly from occupational exposure, travel to endemic areas, recreational activities, or importation of domestic and wild animals, whereas outbreaks in developing countries are most frequently related to normal daily activities, over-crowding, poor sanitation and climatic conditions.</p> <p>Conclusion</p> <p>In the Asia Pacific region, predominantly in developing countries, leptospirosis is largely a water-borne disease. Unless interventions to minimize exposure are aggressively implemented, the current global climate change will further aggravate the extent of the disease problem. Although trends indicate successful control of leptospirosis in some areas, there is no clear evidence that the disease has decreased in the last decade. The efficiency of surveillance systems and data collection varies significantly among the countries and areas within the region, leading to incomplete information in some instances. Thus, an accurate reflection of the true burden of the disease remains unknown.</p

Biogeography of mutualistic fungi cultivated by leafcutter ants

Leafcutter ants propagate co-evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite-marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade-A and Clade-B). The dominant and widespread Clade-A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade-A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade-B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade-A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade-B fungi occur only in South America. Diversity of Clade-A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov–Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot-specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus-growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars