Sleep intensity and the evolution of human cognition

Over the past four decades, scientists have made substantial progress in understanding the evolution of sleep patterns across the Tree of Life. 1 , 2 Remarkably, the specifics of sleep along the human lineage have been slow to emerge. This is surprising, given our unique mental and behavioral capacity and the importance of sleep for individual cognitive performance. 3 - 5 One view is that our species' sleep architecture is in accord with patterns documented in other mammals. 6 We promote an alternative view, that human sleep is highly derived relative to that of other primates. Based on new and existing evidence, we specifically propose that humans are more efficient in their sleep patterns than are other primates, and that human sleep is shorter, deeper, and exhibits a higher proportion of REM than expected. Thus, we propose the sleep intensity hypothesis: Early humans experienced selective pressure to fulfill sleep needs in the shortest time possible. Several factors likely served as selective pressures for more efficient sleep, including increased predation risk in terrestrial environments, threats from intergroup conflict, and benefits arising from increased social interaction. Less sleep would enable longer active periods in which to acquire and transmit new skills and knowledge, while deeper sleep may be critical for the consolidation of those skills, leading to enhanced cognitive abilities in early humans.     

New baseline environmental assessment of mosquito ecology in northern Haiti during increased urbanization

The catastrophic 2010 earthquake in Port‐au‐Prince, Haiti, led to the large‐scale displacement of over 2.3 million people, resulting in rapid and unplanned urbanization in northern Haiti. This study evaluated the impact of this unplanned urbanization on mosquito ecology and vector‐borne diseases by assessing land use and change patterns. Land‐use classification and change detection were carried out on remotely sensed images of the area for 2010 and 2013. Change detection identified areas that went from agricultural, forest, or bare‐land pre‐earthquake to newly developed and urbanized areas post‐earthquake. Areas to be sampled for mosquito larvae were subsequently identified. Mosquito collections comprised five genera and ten species, with the most abundant species being Culex quinquefasciatus 35% (304/876), Aedes albopictus 27% (238/876), and Aedes aegypti 20% (174/876). All three species were more prevalent in urbanized and newly urbanized areas. Anopheles albimanus, the predominate malaria vector, accounted for less than 1% (8/876) of the collection. A set of spectral indices derived from the recently launched Landsat 8 satellite was used as covariates in a species distribution model. The indices were used to produce probability surfaces maps depicting the likelihood of presence of the three most abundant species within 30 m pixels. Our findings suggest that the rapid urbanization following the 2010 earthquake has increased the amount of area with suitable habitats for urban mosquitoes, likely influencing mosquito ecology and posing a major risk of introducing and establishing emerging vector‐borne diseases.     

Oligonucleotide probes applied for sensitive enzyme-amplified electrochemical assay of mercury(II) ions

We developed a novel electrochemical sensor for Hg(2+) detection using two mercury-specific oligonucleotide probes and streptavidin-horseradish peroxidase (HRP) enzymatic signal amplification. The two mercury-specific oligonucleotide probes comprised a thiolated capture probe and a biotinated signal probe. The thiolated capture probe was immobilized on a gold electrode. In the presence of Hg(2+), the thymine-Hg(2+)-thymine (T-Hg(2+)-T) interaction between the mismatched T-T base pairs directed the biotinated signal probe hybridizing to the capture probe and yielded a biotin-functioned electrode surface. HRP was then immobilized on the biotin-modified substrate via biotin-streptavidin interaction. The immobilized HRP catalyzed the oxidation of hydroquinone (H(2)Q) to benzoquinone (BQ) by hydrogen peroxide (H(2)O(2)) and the generated BQ was further electrochemically reduced at the modified gold electrode, producing a readout signal for quantitative detection of Hg(2+). The results showed that the enzyme-amplified electrochemical sensor system was highly sensitive to Hg(2+) in the concentration of 0.5 nM to 1 μM with a detection limit of 0.3 nM, and it also demonstrated excellent selectivity against other interferential metal ions.     

Design and synthesis of pyridone inhibitors of non-nucleoside reverse transcriptase

Next generation NNRTIs are sought which possess both broad spectrum antiviral activity against key mutant strains and a high genetic barrier to the selection of new mutant viral strains. Pyridones were evaluated as an acyclic conformational constraint to replace the aryl ether core of MK-4965 (1) and the more rigid indazole constraint of MK-6186 (2). The resulting pyridone compounds are potent inhibitors of HIV RT and have antiviral activity in cell culture that is superior to other next generation NNRTI’s.     

Strand 6B deformation and residues exposure towards N-terminal end of helix B during proteinase inhibition by Serpins

Serine Protease inhibitors (Serpins) like antithrombin, antitrypsin, neuroserpin, antichymotrypsin, protein C-inhibitor and plasminogen activator inhibitor is involved in important biological functions like blood coagulation, fibrinolysis, inflammation, cell migration and complement activation. Serpins native state is metastable, which undergoes transformation to a more stable state during the process of protease inhibition. Serpins are prone to conformation defects, however little is known about the factors and mechanisms which promote its conformational change and misfolding. Helix B region in serpins is with several point mutations which result in pathological conditions due to polymerization. Helix B analysis for residue burial and cavity was undertaken to understand its role in serpin structure function. A structural overlap and an accessible surface area analysis showed the deformation of strand 6B and exposure of helix B at N-terminal end in cleaved conformation but not in the native and latent conformation of various inhibitory serpins. A cleaved polymer like conformation of antitrypsin also showed deformation of s6B and helix B exposure. Cavity analysis showed that helix B residues were part of the largest cavity in most of the serpins in the native state which increase in size during the transformation to cleaved and latent states. These data for the first time show the importance of strand 6B deformation and exposure of helix B in smooth insertion of the reactive center loop during serpin inhibition and indicate that helix B exposure due to variants may increase its polymer propensity. ABBREVIATIONS: serpin -serine protease inhibitors RCL -reactive center loop ASA -accessible surface area.     

Molecular and structural basis of ESCRT-III recruitment to membranes during archaeal cell division

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Highlights? A conserved protein, CdvA, recruits ESCRT-III to membranes during cell division ? Recruitment is mediated by a peptide-winged helix domain interaction ? We have determined the structure of this complex ? CdvA and a single ESCRT-III protein can drive membrane deformation in vitro     

Taxonomy of Eurotium species isolated from meju

Eurotium strains were isolated from 77 loaves of meju (dried fermented soybeans), in various regions of Korea from 2008 to 2010. Morphological characteristics and DNA sequences of β-tubulin were examined. They were identified as Eurotium amstelodami, E. chevalieri, E. herbariorum, E. repens, E. rubrum, and E. tonophilum. Of these species, E. chevalieri and E. tonophilum had not been previously reported in association with meju. E. chevalieri and E. repens were the species isolated most frequently. This paper summarizes the morphological characteristics of six Eurotium species and provides key to identify the species from meju.