Structure of an Odorant-Binding protein from the Mosquito Aedes aegypti suggests a binding pocket covered by a pH-sensitive “Lid”

Background The yellow fever mosquito, Aedes aegypti, is the primary vector for the viruses that cause yellow fever, mostly in tropical regions of Africa and in parts of South America, and human dengue, which infects 100 million people yearly in the tropics and subtropics. A better understanding of the structural biology of olfactory proteins may pave the way for the development of environmentally-friendly mosquito attractants and repellents, which may ultimately contribute to reduction of mosquito biting and disease transmission. Methodology Previously, we isolated and cloned a major, female-enriched odorant-binding protein (OBP) from the yellow fever mosquito, AaegOBP1, which was later inadvertently renamed AaegOBP39. We prepared recombinant samples of AaegOBP1 by using an expression system that allows proper formation of disulfide bridges and generates functional OBPs, which are indistinguishable from native OBPs. We crystallized AaegOBP1 and determined its three-dimensional structure at 1.85 Å resolution by molecular replacement based on the structure of the malaria mosquito OBP, AgamOBP1, the only mosquito OBP structure known to date. Conclusion The structure of AaegOBP1 ( = AaegOBP39) shares the common fold of insect OBPs with six α-helices knitted by three disulfide bonds. A long molecule of polyethylene glycol (PEG) was built into the electron-density maps identified in a long tunnel formed by a crystallographic dimer of AaegOBP1. Circular dichroism analysis indicated that delipidated AaegOBP1 undergoes a pH-dependent conformational change, which may lead to release of odorant at low pH (as in the environment in the vicinity of odorant receptors). A C-terminal loop covers the binding cavity and this “lid” may be opened by disruption of an array of acid-labile hydrogen bonds thus explaining reduced or no binding affinity at low pH

A multimethod laboratory study

Funding Information: This study was partially funded by FAPERJ and CNPq. Funding Information: The authors acknowledge Fernanda Carvalho for running the differential scanning calorimetry tests on the endodontic files. The Article Processing Charge for the publication of this research was funded by the Coordena\u00E7\u00E3o de Aperfei\u00E7oamento de Pessoal de N\u00EDvel Superior \u2010 Brasil (CAPES) (ROR identifier: 00x0ma614). Publisher Copyright: © 2025 The Author(s). International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.Aim: To evaluate the influence of blade design (conventional, flat and hybrid) and metallurgical properties on the mechanical performance of nickel-titanium endodontic instruments. Methodology: Two hundred and seven NiTi instruments (25 mm in length) with three different blade designs were selected for analysis: conventional (n = 69, CC One Blue, size 25/0.08v), flat (n = 69, Platinum V.EU, size 25/0.06) and hybrid (n = 69, Flash Endo Power, size 25/0.06v). The instruments were evaluated regarding geometric design (scanning electron microscopy), alloy elements composition (energy-dispersive X-ray spectroscopy) and phase transformation temperatures (differential scanning calorimetry). Additionally, their mechanical behaviour was investigated by testing cyclic fatigue resistance, torsional resistance, bending resistance, buckling resistance, cutting efficiency and microhardness. Statistical significance was determined using One-Way anova and Kruskal–Wallis tests (α = 5%). Results: Platinum V.EU and Flash instruments exhibited design inconsistencies within the same lot, including nonstandard positioning and variations in the length of the flat side. All instruments were composed of a nickel-titanium alloy with equiatomic ratios of nickel and titanium. At 20°C, Flash instruments exhibited a mixed R-phase and austenitic arrangement, transitioning fully to austenitic at 36°C, while CC One Blue and Platinum V.EU displayed a complete R-phase at 20°C and retained a mixed R-phase and austenitic arrangement at 36°C. The CC One Blue exhibited superior performance in time to fracture (156 ± 34 s), maximum torque (1.5 N·cm) and buckling strength (372 ± 31 gf) (p <.0001), while no differences were found in maximum rotation angle (p =.602). In terms of flexibility, the Flash (328 gf) and CC One Blue (341 gf) outperformed the Platinum V.EU (376 gf) (p =.006). Flash (121 gf) and CC One Blue (137 gf) also outperformed Platinum V.EU (253 gf) in terms of cutting efficiency (p <.0001). Conversely, the Platinum V.EU demonstrated significantly higher microhardness (386 ± 45 HVN) compared to CC One Blue and Flash (p =.0340). Conclusions: Overall, instruments featuring either flat-side (Platinum V.EU) or hybrid (Flash) active blades demonstrated inferior mechanical performance compared to the conventional nonflat instrument (CC One Blue).publishersversionpublishe

POSTHARVEST CONSERVATION OF STRUCTURAL LONG SHELF LIFE TOMATO FRUITS AND WITH THE MUTANT RIN PRODUCED, IN EDAPHOCLIMATIC CONDITIONS OF THE SOUTHERN STATE OF TOCANTINS

The high temperature of growth environment can affect the postharvest quality of tomato fruits. In this situation, an alternative for the farmers is the use of hybrid cultivars that produce long shelf life fruit with longer postharvest shelf life when compared to normal varieties of fruits. The objective of this research was to compare the postharvest conservation of fruits of structural long shelf life tomato hybrids and with the mutant rin. The fruits evaluated were from fifteen tomato genotypes produced under the edaphoclimatic conditions of the southern State of Tocantins, being four of them long shelf life type hybrids (with rin allele) which were: Tyler, Rebeca, Carmem and AF 13527; nine of them structural long shelf life hybrids: Lumi, Débora Max, Michelli, Tammy, AF 12525, AF 11097, AF 13363, AF 13364 and AF 13525; and two normal fruit cultivars: Santa Clara and Drica. The fruits were harvested at the breaker stage and stored in a controlled environment (20 °C and relative humidity of 60%). The half-life firmness of fruits of genotypes with a structural genotypic long shelf life background ranged from 6.25 to 13.44 days for the genotypes Tammy and AF13525, respectively, not differing from the long shelf life genotypes with rin allele. Despite the fact that daytime temperatures are higher than those recommended for the tomatoes crops, it was observed that if the fruits are stored in appropriate conditions (20 °C and relative humidity of 60%), the color and firmness of the fruits with a long shelf life genotypes with rin allele and structural genotypic background evolve more slowly than the fruits of normal genotypes. Under these conditions, it took the fruits 7 to 8 days to acquire a red color on more than 80% of the surface after being harvested

Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study

Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis

A2ML1 and otitis media: novel variants, differential expression, and relevant pathways

A genetic basis for otitis media is established, however, the role of rare variants in disease etiology is largely unknown. Previously a duplication variant within A2ML1 was identified as a significant risk factor for otitis media in an indigenous Filipino population and in US children. In this report exome and Sanger sequencing was performed using DNA samples from the indigenous Filipino population, Filipino cochlear implantees, US probands, Finnish, and Pakistani families with otitis media. Sixteen novel, damaging A2ML1 variants identified in otitis media patients were rare or low-frequency in population-matched controls. In the indigenous population, both gingivitis and A2ML1 variants including the known duplication variant and the novel splice variant c.4061 + 1 G>C were independently associated with otitis media. Sequencing of salivary RNA samples from indigenous Filipinos demonstrated lower A2ML1 expression according to the carriage of A2ML1 variants. Sequencing of additional salivary RNA samples from US patients with otitis media revealed differentially expressed genes that are highly correlated with A2ML1 expression levels. In particular, RND3 is upregulated in both A2ML1 variant carriers and high-A2ML1 expressors. These findings support a role for A2ML1 in keratinocyte differentiation within the middle ear as part of otitis media pathology and the potential application of ROCK inhibition in otitis media