Odorant-binding proteins (OBPs) are small soluble proteins whose biological function is believed to be facilitating olfaction by assisting the transport of volatile chemicals in both vertebrate and ...insect sensory organs, where they are secreted. Their capability to interact with a broad range of hydrophobic compounds combined with interesting features such as being small, stable, and easy to produce and modify, makes them suitable targets for applied research in various industrial segments, including textile, cosmetic, pesticide, and pharmaceutical, as well as for military, environmental, health, and security field applications. In addition to reviewing already established biotechnological applications of OBPs, this paper also discusses their potential use in prospecting of new technologies. The development of new products for insect population management is currently the most prevailing use for OBPs, followed by biosensor technology, an area that has recently seen a significant increase in studies evaluating their incorporation into sensing devices. Finally, less typical approaches include applications in anchorage systems and analytical tools.
Key points
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Odorant-binding proteins (OBPs) present desired characteristics for applied research
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OBPs are mainly used for developing new products for insect population control
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Incorporation of OBPs into chemosensory devices is a growing area of study
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Less conventional uses for OBPs include anchorage systems and analytical purposes
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Graphical Abstract
Zika virus infection and dengue and chikungunya fevers are emerging viral diseases that have become public health threats. Their aetiologic agents are transmitted by the bite of genus Aedes ...mosquitoes. Without effective therapies or vaccines, vector control is the main strategy for preventing the spread of these diseases. Increased insecticide resistance calls for biorational actions focused on control of the target vector population. The chitin required for larval survival structures is a good target for biorational control. Chitin synthases A and B (CHS) are enzymes in the chitin synthesis pathway. Double-stranded RNA (dsRNA)-mediated gene silencing (RNAi) achieves specific knockdown of target proteins. Our goal in this work, a new proposed RNAi-based bioinsecticide, was developed as a potential strategy for mosquito population control. DsRNA molecules that target five different regions in the CHSA and B transcript sequences were produced in vitro and in vivo through expression in E. coli HT115 and tested by direct addition to larval breeding water. Mature and immature larvae treated with dsRNA targeting CHS catalytic sites showed significantly decreased viability associated with a reduction in CHS transcript levels. The few larval and adult survivors displayed an altered morphology and chitin content. In association with diflubenzuron, this bioinsecticide exhibited insecticidal adjuvant properties.
We performed an in-depth analysis of the ABC gene family in Aedes aegypti (Diptera: Culicidae), which is an important vector species of arthropod-borne viral infections such as chikungunya, dengue, ...and Zika. Despite its importance, previous studies of the Arthropod ABC family have not focused on this species. Reports of insecticide resistance among pests and vectors indicate that some of these ATP-dependent efflux pumps are involved in compound traffic and multidrug resistance phenotypes.
We identified 53 classic complete ABC proteins annotated in the A. aegypti genome. A phylogenetic analysis of Aedes aegypti ABC proteins was carried out to assign the novel proteins to the ABC subfamilies. We also determined 9 full-length sequences of DNA repair (MutS, RAD50) and structural maintenance of chromosome (SMC) proteins that contain the ABC signature.
After inclusion of the putative ABC proteins into the evolutionary tree of the gene family, we classified A. aegypti ABC proteins into the established subfamilies (A to H), but the phylogenetic positioning of MutS, RAD50 and SMC proteins among ABC subfamilies-as well as the highly supported grouping of RAD50 and SMC-prompted us to name a new J subfamily of A. aegypti ABC proteins.
The objective of the present study was to investigate metal(loid)s in soils, in the trunk xylem sap and in the leaves of the
plant located near the highway with high vehicle traffic in agricultural ...regions and near landfills, and to assess the transfer of metal(loid)s from soil to plant and possible health risk assessment. Trunk xylem sap, leaves and soil samples were collected at three sites near the highway. The analysis of trace elements was carried out using inductively coupled plasma optical emission spectroscopy (ICP OES). In the three soil sampling sites far from the highway edge, 15 elements were quantified. The concentrations of elements in the soil presented in greater proportions in the distance of 5 m in relation to 20 and 35 m. The metal(loid)s content in the study soil was higher than in other countries. The concentrations of Al, Cu, Fe, Mg, Mn, P, Se and Zn in the xylem sap were much higher than the leaves. The values of transfer factor of P, Mg and Mn from soil to the xylem sap and transfer factor of P from soil to leaf were greater than 1, indicating that the specie have a significant phytoremediation and phytoextraction potential. This plant has a tendency to accumulate As, Cd and Cr in its leaf tissues. The chronic hazard index (HI) values recorded in this study were above 1 for adults and adolescents. It is concluded that the soil, the trunk xylem sap and leaves of this plant are contaminated by heavy metals. Ingestion of the trunk xylem sap of this plant can cause toxicity in humans if ingested in large quantities and in the long term; therefore, its consumption should be avoided.
Tetradenia riparia
(Lamiaceae) is native to Central Africa popularly known as myrrh, used in folk medicine to treat various diseases like malaria, gastroenteritis, and tropical skin disease. This ...research was to evaluate the antioxidant and antibacterial activities of the crude extract (CE) and fractions (FR) of the
T. riparia
by classical chromatography. The CE of
T. riparia
leaves was submitted to column chromatographic fractionation to obtain four fractions of the interest, which were identified by nuclear magnetic resonance and gas chromatograph coupled to mass spectrum: FR-I (abieta-7,9(11)-dien-13-β-ol), FR-II (Ibozol), FR-III (8 (14), 15-sandaracopimaradiene-2α, 18-diol and 8 (14), 15-sandaracopimaradiene-7α, 18-diol), and FR-IV (Astragalin, Boronolide and Luteolin). Total phenol content of CE and FR were measured, and antioxidant action by methods of DPPH (2,2-diphenyl-1-picrylhydrazyl), β-carotene/linoleic acid system, and ferric reducing/antioxidant power (FRAP) and the antibacterial activity was evaluated by the broth microdilution method with the determination of the minimum inhibitory concentration (MIC). The FR-IV presented antioxidant potential with 181.67 μg gallic acid/mg, IC
50
of 0.61 μg/mL by DPPH method, 55.61% oxidation protection by β-carotene/linoleic acid system and 4.59 µM ferrous sulfate/mg of sample by FRAP, and the FR-I showed higher antibacterial potential on the strain
Staphylococcus aureus
with MIC 0.98 μg/mL
, Enterococcus faecalis
and
Bacillus cereus
with MIC 31.2 μg/mL. Thus, the fractionation of CE was extremely important to detect fractions with potential activities, and investigations are necessary regarding the mechanism of action and action in vivo.
Graphical Abstract
Aedes aegypti is a highly anthropophilic mosquito responsible for the transmission of dengue and yellow fever around the world. Like other mosquitoes, the biting and host preference behaviors of this ...disease vector are largely influenced by its sense of smell, which is presumably facilitated by G protein-coupled receptor signaling cascades. Here, we report the identification and characterization of AaOr7, the first candidate odorant receptor from Ae. aegypti. This receptor displays extremely high primary amino acid conservation with AgOr7 another candidate odorant receptor identified in the Aftrotropical malaria vector, Anopheles gambiae as well as several previously identified candidate odorant receptors in Drosophila melanogaster and other insects. Its transcript is expressed in adult chemosensory tissues and during several stages of Ae. aegypti development. Within the adult olfactory system, AaOr7 protein is found specifically within most antennal and maxillary palp sensilla, as well as in a subset of proboscis sensilla. These results are consistent with a role for AaOr7 in olfaction and gustation supporting the hypothesis that AaOr7 and its orthologs may be of general importance to chemosensory processes throughout the lifetime of an insect.
The detection of biomarkers is the future of non-invasive medical diagnosis and screening. Discovery and identification of reliable disease specific volatile organic compounds is dependent on ...repeatable, accurate analysis of trace level gaseous analytes mainly in breath samples. Natural variety of the olfactory systems and the compounds capable of gas molecules binding creates wide possibilities of acquisition and implementation of the biological elements for construction of the biosensors for different applications, with special emphasis on healthcare and medical areas. Early and fast diagnosis of patient's condition, including respiratory system diseases, as well as on-time launch of suitable treatment are the critical factors influencing on public health and efficiency of clinical trials. Conventional techniques of diagnosis of the respiratory system diseases are usually time-consuming, require centralized laboratories, experienced personnel and expensive equipment. Recently developed biosensors take advantage of micro- and nanotechnology achievements, which significantly improve their metrological parameters. A transfer of the biosensors from scientific laboratories to actual clinic diagnostics is limited and requires overcoming of critical obstacles. Potential use of olfactory receptors and elements mimicking their operation in artificial olfaction for their use in biosensors in disease diagnosis are presented. We review recent progress in olfactory-based biosensors employing different biological units in light of future developments in medical diagnosis with emphasis on examples where biological components have been employed to detect biomarkers. Also, significant advances over the last years were discussed and features of fabrication in the perspective of odorant sensing applications. Pioneering studies that greatly impacted the field of biosensing are critically reviewed along with future challenges to overcome.
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•Challenges in diseases diagnosis.•Olfactory-based biosensors as non-invasive and early detection tools.•Olfactory-based primary transducers.•Advantages of micro- and nanotechnology.•Future prospects of olfactory-based biosensors.
Abstract
Background
Deposition of Schistosoma mansoni eggs in the brain of patients with hepatosplenic schistosomiasis (HS-SM) is frequent and usually asymptomatic. However, it is questioned whether ...it could cause seizures. Thus, we investigated the occurrence of seizures in these patients and also searched for parameters associated with this disorder.
Methods
In a cross-sectional survey, we compared 128 patients with HS-SM with 102 patients with portal hypertension due to compensated chronic hepatic disease of other etiologies. A standardized questionnaire, emphasizing epilepsy-related parameters, was applied to all participants.
Results
Eight (6.3%) patients with HS-SM had a history of seizures, whereas this condition was reported by three (2.9%) individuals from the comparison group (p=0.354). None of the variables were associated with the occurrence of seizures, either in univariate or in multivariate analysis.
Conclusions
The frequency of seizures was similar in both study groups. However, it was higher than that described in population-based studies. Thus, we hypothesize that HS-SM individuals may have a higher frequency of seizure. The lack of difference between the two study groups may be explained by the inclusion of cases of HS-MS overlapping other chronic liver diseases in the comparison group, because this finding is relatively common in schistosome-endemic areas.
In the field of cancer detection, the development of affordable, quick, and user-friendly sensors capable of detecting various cancer biomarkers, including those for lung cancer (LC), holds utmost ...significance. Sensors are expected to play a crucial role in the early-stage diagnosis of various diseases. Among the range of options, sensors emerge as particularly appealing for the diagnosis of various diseases, owing to their cost-effectiveness, simplicity, and promising analytical performance. There is growing interest in the application of molecularly imprinted polymers (MIPs) as promising recognition elements in gas sensors. MIPs, as a leading technology for sensing analytes where no suitable bioreceptor exists, are commonly used in artificial sensing that can be applied in key fields like early disease diagnostics, based on the detection of volatile biomarkers. There is an extensive demand for early, non-invasive detection of various diseases and for the self-monitoring of health conditions. Detection of biomarkers in point-of-care mode remains challenging and is limited by various factors. Hence, breath analysis has received enormous attention in healthcare due to its relatively low cost, non-invasive sampling method, and rapid detection capabilities. The latest developments in MIP-based sensors and their utility in disease diagnosis through the detection of volatile biomarkers are comprehensively and critically evaluated in this review. Furthermore, the challenges and perspectives of MIP-based sensors are elaborated upon, with a view towards introduction to the market and successful commercialization.
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•Various biomarkers and the challenges in their detection.•MIP-based gas sensors as promising tools for the early diagnosis.•MIPs application opportunities where no suitable bioreceptors exist.•The latest developments in MIP-based gas sensors.•Challenges and prospects for market introduction.
The effects of lufenuron, a chitin synthesis inhibitor, on oogenesis of
Rhodnius prolixus were evaluated. Lufenuron-treated females lay eggs that are pink, but change color with time, acquiring a ...gray color. The eggs are abnormal in shape and become dehydrated. The percentage of eggs that hatch is decreased compared with the eggs from non-treated females. Digestion of ovaries with KOH yielded an insoluble white material, which was identified as chitin based on infrared and proton NMR spectral analyses along with standard commercial chitin. Glucosamine was detected by HPLC as the major product of acid hydrolysis of the KOH-insoluble material prepared from the ovary. Furthermore, presence of chitin in ovary was confirmed through fluorescent microscopy technique using a wheat germ agglutinin probe and by re-treatment with
Streptomyces griseus chitinase that resulted in reduction of chitin-derived fluorescence. Micrographs of ovaries, from animals treated with lufenuron, showed some space between the follicular epithelium and the oocyte membrane. The
in vivo incorporation of radioactive N-acetylglucosamine into chitin was inhibited by the presence of lufenuron. These data suggest that chitin present in ovaries of
R. prolixus is an important component of the eggs and is involved in oogenesis. Exposure to lufenuron reduces the size of oocytes, number of chorionated oocytes, and also the incorporation of N-acetylglucosamine into chitin in the ovaries. In addition, lufenuron-induced oosorption, decreased the number of eggs laid, modified egg shape and color and reduced the viability of the eggs. Therefore, chitin or chitin-like component of ovaries may be considered as a new target for controlling
R. prolixus populations.
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