scholarly journals Simplified artificial blood feeding and oral infection method for mosquitoes

2020 ◽  
Author(s):  
Thiago Nunes Pereira ◽  
Fabiano Duarte Carvalho ◽  
Lidia Henrique da Silva ◽  
Silvana Faria de Mendonça ◽  
Luciano Andrade Moreira

ABSTRACTMosquitoes such as Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of many pathogens that greatly affect humankind. The maintenance of these mosquitoes in laboratory permit different studies that can help understanding their biology, as well as the vector-pathogen interaction. In addition to sugar meals, the blood feeding is essential for maintenance of the reproductive cycle in several vectors. The main blood sources for many mosquito colonies are direct feeding on live animal or the use of human/animal blood through artificial feeders. However, this latter process has some disadvantages, as artificial feeders can be very laborious for assembly and decontamination. Based on these observations, a simplified technique for feeding and artificial infection was developed with cotton-pads soaked (CS) and blood or blood and viral supernatant to simulate an artificial infection. The efficiency of the CS technique was investigated through the number of mosquitoes fed/infected, when compared to their respective control group. The CS technique, with blood at room temperature, promoted a feeding rate of 61.4% for Ae. albopictus, 70.8% for Cx. quinquefasciatus and 17% for Ae. aegypti. The control group (Hemotec-feeding) presented 47.9%, 16.5% and 59.1% of feeding success, respectively. To improve the CS technique for Ae. aegypti mosquitoes, the procedure was then performed with blood at 38°C, which was possible to observe a feeding rate of 47.3%, in comparison to 53.2% for the control group (Hemotec). When using the CS technique for artificial infection with Mayaro virus, more than 80% of infection was observed for Ae. aegypti and 100% for Ae. albopictus. In the traditional infection technique (glass feeder), the infection rate was 90% (Ae. aegypti) and 96.6% (Ae. albopictus). For Cx. quinquefasciatus, the infection was positive only with the CS technique, resulting in 1 (5%) mosquito infected with Mayaro virus. Our results suggest that this simplified technique of low-cost feeding and easy assembly, offers good results for feeding (maintenance of colonies) and artificial infection of different species of mosquitoes.

2011 ◽  
Vol 393-395 ◽  
pp. 1024-1028 ◽  
Author(s):  
Hong Zhang ◽  
Jun Wei Wang ◽  
Sheng Zhong Dong ◽  
Fang Xu Xu ◽  
Sheng Hou Wang

The optimization of extraction of cordycepin from fruiting body of Cordyceps militaris YCC-01 by water extraction, ethanol extraction, ultrasonic extraction, and synergistic extraction is studied in this paper. The optimal conditions, water extraction at 85°C for 2.5h plus ultrasonic extraction at 600W for 35min, were determined through high performance liquid chromatography (HPLC). The dried fruiting body of cordycepin content was 9.559 mg/g by this synergistic extraction method. The yield was 66.2% higher than the control group 85°C water extraction 2.5h and 11.3% higher than the room temperature ultrasonic extraction 35min. This method has a short extraction time, low cost, low loss of active ingredients and other characteristics with good prospects.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shailabh Kumar ◽  
Felix J. H. Hol ◽  
Sujit Pujhari ◽  
Clayton Ellington ◽  
Haripriya Vaidehi Narayanan ◽  
...  

AbstractMosquito bites transmit a number of pathogens via salivary droplets deposited during blood-feeding, resulting in potentially fatal diseases. Little is known about the genomic content of these nanodroplets, including the transmission dynamics of live pathogens. Here we introduce Vectorchip, a low-cost, scalable microfluidic platform enabling high-throughput molecular interrogation of individual mosquito bites. We introduce an ultra-thin PDMS membrane which acts as a biting interface to arrays of micro-wells. Freely-behaving mosquitoes deposit saliva droplets by biting into these micro-wells. By modulating membrane thickness, we observe species-dependent differences in mosquito biting capacity, utilizable for selective sample collection. We demonstrate RT-PCR and focus-forming assays on-chip to detect mosquito DNA, Zika virus RNA, as well as quantify infectious Mayaro virus particles transmitted from single mosquito bites. The Vectorchip presents a promising approach for single-bite-resolution laboratory and field characterization of vector-pathogen communities, and could serve as a powerful early warning sentinel for mosquito-borne diseases.


2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Mohd Farihan Md Yatim ◽  
Aishah Hani Azil ◽  
Nazarudin Safian ◽  
Ahmad Firdaus Mohd Salleh ◽  
Mohd Khadri Shahar

The use of live animal to blood feeding mosquito colony is proven to be expensive and inconvenient. As an alternative, artificial feeding (AF) is used to rear mosquito colony. The use of synthetic membrane in AF provided a more convenient method as compared to natural membrane which require extensive preparation. In this study, three synthetic membranes were compared (Parafilm-M, Polytetrafluoroethylene tape or PTFE tape and collagen sausage casing) to blood feeding Aedes aegypti. The membranes were incorporated with our in-house developed device named as Digital Thermo Mosquito Blood Feeder (DITMOF) to heat cattle blood for mosquito feeding. Results showed that PTFE tape recorded the highest blood feeding rate (95.00% ± 1.67%) with significant mean difference (p <0.001) as compared to both Parafilm-M (72.00% ± 2.60%) and collagen sausage casing (71.50% ± 3.50%). However, there was no difference in term of fecundity for mosquito feed with all three membranes tested (p=0.292). In conclusion, PTFE tape should be considered as the preferred membrane to blood feeding Ae. aegypti. Furthermore, this artificial blood feeding system, DITMOF successfully feed Ae. aegypti conveniently and effectively, thus should be further tested to feed other mosquito species.


Author(s):  
A. Farkhutdinova

The expediency of using the probiotic drug Biolax-U in the rations of lactating and dry cows of Black-and-White breed has been studied and scientifically proved. The influence of this drug on the morphological and biochemical parameters of animal blood has been determined. The composition of the probiotic drug Biolax-U consists of eight strains of a balanced complex of living lactic acid bacteria, yeast and actinomycetes, as well as biologically active substances. For experimental studies conducted on 2 groups of cows have been selected by the method of pairs-analogs, the influence of feeding of feed have been prepared with the use of the microbiological drug with probiotic action Biolax-U on feed consumption, morphological and biochemical changes in blood has been studied. Analysis of the rations of cows indicates that the content of calcium, phosphorus, magnesium, sulfur and trace elements such as manganese, copper, zinc and cobalt in the feed has been reduced. It has been found by studies that the use of probiotic drug Biolax-U had the positive influence on the feed intake, digestibility and better assimilation of feed nutrients and contributed to the improvement of blood morphological and biochemical parameters. For example, in animals of the experimental group hemoglobin has increased by 3,6 % (Р < 0,05), red blood cells by 10,1 (P ≤ 0,05), the content of leukocytes by 4,43, carotene by 9,6, glucose by 3,4; reserve alkalinity by 15,6, calcium by 19,4 (P ≤ 0,01), and phosphorus by 18,4 % compared with the control group of animals. During the lactation significantly improved hematological parameters including alkalinity reserve by 5,11 %, calcium level by 11,1, phosphorus by 8,6, hemoglobin by 14,2 %, the content of erythrocytes by 12,3, leukocyte by 3,86, and carotene 11,1 % against the parameters of animals of control group. The improvement of morphological and biochemical parameters of blood of cows indicates about stimulating effect on hematopoiesis and the general clinical condition of animals that contributes to the improvement of metabolic processes when using feed prepared with the use of microbiological drug with probiotic action Biolax-U.


2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.


2021 ◽  
Vol 536 ◽  
pp. 147809
Author(s):  
Mingming Luo ◽  
Zhao Liang ◽  
Chao Liu ◽  
Xiaopeng Qi ◽  
Mingwei Chen ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1489
Author(s):  
Bhaskar Parida ◽  
Saemon Yoon ◽  
Dong-Won Kang

Materials and processing of transparent electrodes (TEs) are key factors to creating high-performance translucent perovskite solar cells. To date, sputtered indium tin oxide (ITO) has been a general option for a rear TE of translucent solar cells. However, it requires a rather high cost due to vacuum process and also typically causes plasma damage to the underlying layer. Therefore, we introduced TE based on ITO nanoparticles (ITO-NPs) by solution processing in ambient air without any heat treatment. As it reveals insufficient conductivity, Ag nanowires (Ag-NWs) are additionally coated. The ITO-NPs/Ag-NW (0D/1D) bilayer TE exhibits a better figure of merit than sputtered ITO. After constructing CsPbBr3 perovskite solar cells, the device with 0D/1D TE offers similar average visible transmission with the cells with sputtered ITO. More interestingly, the power conversion efficiency of 0D/1D TE device was 5.64%, which outperforms the cell (4.14%) made with sputtered-ITO. These impressive findings could open up a new pathway for the development of low-cost, translucent solar cells with quick processing under ambient air at room temperature.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 467
Author(s):  
Emília Mendes da Silva Santos ◽  
Isabela Regina Alvares da Silva Lira ◽  
Hugo Moraes Meira ◽  
Jaciana dos Santos Aguiar ◽  
Raquel Diniz Rufino ◽  
...  

In this study, a new formulation of low-cost, biodegradable, and non-toxic biosurfactant by Candida sphaerica UCP 0995 was investigated. The study was conducted in a bioreactor on an industrial waste-based medium, and a central composite rotatable design was used for optimization. The best results, namely a 25.22 mN/m reduction in surface tension, a biosurfactant yield of 10.0 g/L, and a critical micelle concentration of 0.2 g/L, were achieved in 132 h at an agitation speed of 175 rpm and an aeration rate of 1.5 vvm. Compositional and spectroscopic analyses of the purified biosurfactant by chemical methods, Fourier transform infrared spectroscopy, and nuclear magnetic resonance suggested that it is a glycolipid-type biosurfactant, and it showed no cytotoxicity in the MTT assay. The biosurfactant, submitted to different formulation methods as a commercial additive, remained stable for 120 days at room temperature. Tensioactive properties and stability were evaluated at different pH values, temperatures, and salt concentrations. The biosurfactant obtained with all formulation methods demonstrated good stability, with tolerance to wide ranges of pH, temperature and salinity, enabling application under extreme environmental conditions. Bioremediation tests were performed to check the efficacy of the isolated biosurfactant and the selected microbial species in removing oil from soil. The results demonstrated that the biosurfactant produced has promising properties as an agent for the bioremediation of contaminated soil.


2021 ◽  
Vol 2 (2) ◽  
pp. 325-334
Author(s):  
Neda Javadi ◽  
Hamed Khodadadi Tirkolaei ◽  
Nasser Hamdan ◽  
Edward Kavazanjian

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jose Recatala-Gomez ◽  
Pawan Kumar ◽  
Ady Suwardi ◽  
Anas Abutaha ◽  
Iris Nandhakumar ◽  
...  

Abstract The best known thermoelectric material for near room temperature heat-to-electricity conversion is bismuth telluride. Amongst the possible fabrication techniques, electrodeposition has attracted attention due to its simplicity and low cost. However, the measurement of the thermoelectric properties of electrodeposited films is challenging because of the conducting seed layer underneath the film. Here, we develop a method to directly measure the thermoelectric properties of electrodeposited bismuth telluride thin films, grown on indium tin oxide. Using this technique, the temperature dependent thermoelectric properties (Seebeck coefficient and electrical conductivity) of electrodeposited thin films have been measured down to 100 K. A parallel resistor model is employed to discern the signal of the film from the signal of the seed layer and the data are carefully analysed and contextualized with literature. Our analysis demonstrates that the thermoelectric properties of electrodeposited films can be accurately evaluated without inflicting any damage to the films.


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