scholarly journals Optimization of the feeding rate of Anopheles farauti s.s. colony mosquitoes in direct membrane feeding assays

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lincoln Timinao ◽  
Rebecca Vinit ◽  
Michelle Katusele ◽  
Louis Schofield ◽  
Thomas R. Burkot ◽  
...  
Keyword(s):  
Surface Area ◽  
Blood Volume ◽  
Feeding Rate ◽  
Water Bath ◽  
Starvation Period ◽  
Mosquito Density ◽  
Feeding Rates ◽  
Dark Blood ◽  
Anopheles Farauti ◽  
Membrane Feeding

Abstract Background Direct membrane feeding assays (DMFA) are an important tool to study parasite transmission to mosquitoes. Mosquito feeding rates in these artificial systems require optimization, as there are a number of factors that potentially influence the feeding rates and there are no standardized methods that apply to all anopheline species. Methods A range of parameters prior to and during direct membrane feeding (DMF) were evaluated for their impact on Anopheles farauti sensu stricto feeding rates, including the starving conditions and duration of starving prior to feeding, membrane type, DMF exposure time, mosquito age, feeding in the light versus the dark, blood volume, mosquito density and temperature of water bath. Results The average successful DMFA feeding rate for An. farauti s.s. colony mosquitoes increased from 50 to 85% when assay parameters were varied. Overnight starvation and Baudruche membrane yielded the highest feeding rates but rates were also affected by blood volume in the feeder and the mosquito density in the feeding cups. Availability of water during the pre-feed starvation period did not significantly impact feeding rates, nor did the exposure duration to blood in membrane feeders, the age of mosquitoes (3, 5 and 7 days post-emergence), feeding in the light versus the dark, or the temperature (34 °C, 38 °C, 42 °C and 46 °C) of the water bath. Conclusion Optimal feeding conditions in An. farauti s.s. DMFA were to offer 50 female mosquitoes in a cup (with a total surface area of ~ 340 cm2 with 1 mosquito/6.8 cm2) that were starved overnight 350–500 µL of blood (collected in heparin-coated Vacutainer tubes) per feeder in feeders with a surface area ~ 5 cm2 (with a maximum capacity of 1.5 mL of blood) via a Baudruche membrane, for at least 10–20 min. Graphical Abstract

scholarly journals Optimization of the Feeding rate of Anopheles Farauti Colony Mosquitoes in Direct Membrane Feeding Assays

2021 ◽  
Author(s):  
Lincoln Timinao ◽  
Rebecca Vinit ◽  
Michelle Katusele ◽  
Thomas R Burkot ◽  
Louis Schofield ◽  
...  
Keyword(s):  
Surface Area ◽  
Blood Volume ◽  
Feeding Rate ◽  
Total Surface Area ◽  
Water Bath ◽  
Starvation Period ◽  
Mosquito Density ◽  
Feeding Rates ◽  
Anopheles Farauti ◽  
Membrane Feeding

Abstract Background: Direct membrane feeding assays (DMFA) are an important tool to study parasite transmission to mosquitoes. Mosquito feeding rates in these artificial systems require optimization as there are a number of factors that potentially influence the feeding rates and there are no standardized methods that apply to all Anopheline species.Methods: A range of parameters prior to and during direct membrane feeding (DMF) were evaluated for their impact on Anopheles farauti feeding rates; including the starving conditions and duration of starving prior to feeding, membrane type, DMF exposure time, mosquito age, illumination level, blood volume, mosquito density and temperature of water bath. Results: The average successful DMFA feeding rate for An. farauti colony mosquitoes increased from 50 % to 85 % when assay parameters were varied. Overnight starvation and Baudruche membrane yielded the highest feeding rates but rates were also affected by blood volume in the feeder and the mosquito density in the feeding cups. Availability of water during the pre-feed starvation period did not significantly impact feeding rates, nor did the exposure duration to blood in membrane feeders nor, the age of mosquitoes (3, 5 and 7 days post-emergence), illumination during feeding or the temperature (34 °C, 38 °C, 42 °C and 46 °C) of the water bath.Conclusion: Optimal feeding conditions in An. farauti DMFA were to offer 50 female mosquitoes in a cup (with a total surface area of ~340 cm2 with 1 mosquito / 6.8 cm2) that were starved overnight 350-500 µL of blood (collected in heparin coated vacutainers) per feeder in feeders with a surface area ~5 cm2 (with a maximum capacity of 1.5 mL of blood) via a Baudruche membrane, for at least 10-20 min.

scholarly journals Efficacy of Blood Sources and Artificial Blood Feeding Methods in Rearing of Aedes aegypti (Diptera: Culicidae) for Sterile Insect Technique and Incompatible Insect Technique Approaches in Sri Lanka

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Nayana Gunathilaka ◽  
Tharaka Ranathunge ◽  
Lahiru Udayanga ◽  
Wimaladharma Abeyewickreme
Keyword(s):  
Feeding Rate ◽  
Mass Rearing ◽  
Blood Feeding ◽  
Metal Plate ◽  
Feeding Rates ◽  
Artificial Membrane ◽  
Plate Method ◽  
Membrane Feeding ◽  
Feeding Technique ◽  
One Way Anova

Introduction. Selection of the artificial membrane feeding technique and blood meal source has been recognized as key considerations in mass rearing of vectors. Methodology. Artificial membrane feeding techniques, namely, glass plate, metal plate, and Hemotek membrane feeding method, and three blood sources (human, cattle, and chicken) were evaluated based on feeding rates, fecundity, and hatching rates of Aedes aegypti. Significance in the variations among blood feeding was investigated by one-way ANOVA, cluster analysis of variance (ANOSIM), and principal coordinates (PCO) analysis. Results. Feeding rates of Ae. aegypti significantly differed among the membrane feeding techniques as suggested by one-way ANOVA (p<0.05). The metal plate method was identified as the most efficient and cost-effective feeding technique. Blood feeding rate of Ae. aegypti was higher with human blood followed by cattle and chicken blood, respectively. However, no significant difference was observed from the mosquitoes fed with cattle and human blood, in terms of fecundity, oviposition rate, and fertility as suggested by one-way ANOVA (p>0.05). Conclusions. Metal plate method could be recommended as the most effective membrane feeding technique for mass rearing of Ae. aegypti, due to its high feeding rate and cost effectiveness. Cattle blood could be recommended for mass rearing Ae. aegypti.

scholarly journals Quantitative Measurement of Cerebral Blood Flow and Cerebral Blood Volume after Cerebral Ischaemia

1986 ◽  
Vol 6 (3) ◽  
pp. 338-341 ◽  
Author(s):  
Nicholas V. Todd ◽  
Piero Picozzi ◽  
H. Alan Crockard
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Blood Volume ◽  
Quantitative Measurement ◽  
Cerebral Blood Volume ◽  
Vessel Occlusion ◽  
Permeability Surface ◽  
Area Product ◽  
Hydrogen Clearance ◽  
Clearance Technique

CBF obtained by the hydrogen clearance technique and cerebral blood volume (CBV) calculated from the [14C]dextran space were measured in three groups of rats subjected to temporary four-vessel occlusion to produce 15 min of ischaemia, followed by 60 min of reperfusion. In the control animals, mean CBF was 93 ± 6 ml 100 g−1 min−1, which fell to 5.5 ± 0.5 ml 100 g−1 min−1 during ischaemia. There was a marked early postischaemic hyperaemia (262 ± 18 ml 100g−1 min−1), but 1 h after the onset of ischaemia, there was a significant hypoperfusion (51 ± 3 ml 100 g−1 min−1). Mean cortical dextran space was 1.58 ± 0.09 ml 100 g−1 prior to ischaemia. Early in reperfusion there was a significant increase in CBV (1.85 ± 0.24 ml 100 g−1) with a decrease during the period of hypoperfusion (1.33 ± 0.03 ml 100 g−1). Therefore, following a period of temporary ischaemia, there are commensurate changes in CBF and CBV, and alterations in the permeability–surface area product at this time may be due to variations in surface area and not necessarily permeability.

Pulmonary angiotensin-converting enzyme substrate hydrolysis during exercise

1992 ◽  
Vol 72 (5) ◽  
pp. 1868-1886 ◽  
Author(s):  
J. Dupuis ◽  
C. A. Goresky ◽  
J. W. Ryan ◽  
J. L. Rouleau ◽  
G. G. Bach
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Surface Area ◽  
Blood Volume ◽  
Extravascular Lung Water ◽  
Central Blood Volume ◽  
Converting Enzyme ◽  
Lung Water ◽  
Vascular Surface ◽  
Enzyme Substrate ◽  
Exercise Induced

We examined exercise-induced changes in indicator-dilution estimates of the angiotensin-converting enzyme first-order kinetic parameter, the ratio of a normalized maximal enzymatic conversion rate to the Michaelis constant (Amax/Km), which, under stable enzymatic conditions, will vary with the pulmonary vascular surface area accessible to vascular substrate, the extravascular lung water (an index of the proportion of lung tissue perfused), and the central blood volume (from pulmonary trunk to aorta). Experiments were performed in 10 mongrel dogs at rest and through two increasing levels of treadmill exercise, with the use of two vascular space tracers (labeled erythrocytes and albumin), a water space tracer ([1,8–14C]-octanediol), and a vascular endothelium surface area marker, benzoyl-Phe-Gly-Pro ([3H]BPGP), which is a pharmacologically inactive angiotensin-converting enzyme substrate. The exercise-induced increase in cardiac output was accompanied by a linear increase in central blood volume, and dilutional extravascular lung water rapidly increased to an asymptotic proportion close to 100% of postmortem vascular lung water. There was an average 55% [3H]BPGP hydrolysis, which did not vary with flow, and the computed Amax/Km increased linearly with exercise. We conclude that exercise results in complete lung tissue recruitment and increases the pulmonary vascular surface area available for BPGP hydrolysis linearly with flow, so that pulmonary vascular recruitment continues after full tissue recruitment.

Hematocrit, blood volume, and surface area of dried blood spots – a quantitative model

2020 ◽  
Vol 12 (4) ◽  
pp. 555-560 ◽  
Author(s):  
Mervat M. Alsous ◽  
Ahmed F. Hawwa ◽  
James C. McElnay
Keyword(s):  
Surface Area ◽  
Blood Volume ◽  
Dried Blood Spots ◽  
Quantitative Model ◽  
Blood Spots

Comparative Field Energetics of Two Macropod Marsupials and a Ruminant.

1990 ◽  
Vol 17 (6) ◽  
pp. 591 ◽  
Author(s):  
KA Nagy ◽  
GD Sanson ◽  
NK Jacobsen
Keyword(s):  
Feeding Rate ◽  
Energy Content ◽  
Metabolizable Energy ◽  
Ecological Modelling ◽  
Feeding Rates ◽  
Doubly Labelled Water ◽  
Water Influx ◽  
Scaling Relationship ◽  
Field Metabolic Rates ◽  
Free Ranging

Field metabolic rates (FMRs) and water influx rates were measured via the doubly labelled water method in wild Tasmanian pademelons and grey kangaroos living in the Jock Marshall Reserve at Clayton, Victoria, and in wild black-tailed deer free-ranging within a nature reserve at Davis, California. Deer expended more than 3 times more energy per day than similar sized grey kangaroos. Feeding rates required to achieve energy balance were estimated from FMRs along with an estimate of metabolizable energy content of the food. The estimated feeding rates for pademelons and kangaroos were combined with similar values for 5 other species of macropods to calculate an allometric (scaling) relationship for food requirements of macropod marsupials. Feeding rate had the following relationship to body mass: g food (DM) consumed per day = 0.20 g body mass0.79 (r2 = 0.94). The findings reported herein should be useful for predicting the approximate food requirements of free-ranging macropods and deer for purposes of ecological modelling, conservation efforts and management programmes.

Impacts of water temperature on the physiology and behaviours of the sea urchins Heliocidaris crassispina and Mesocentrotus nudus that reflect their range extension and disappearance in the Oga Peninsula, northern Honshu, Japan

2020 ◽  
Author(s):  
Wenping Feng ◽  
Nobuyasu Nakabayashi ◽  
Eri Inomata ◽  
Masakazu N. Aoki ◽  
Yukio Agatsuma
Keyword(s):  
Low Temperature ◽  
Native Species ◽  
Feeding Rate ◽  
Sea Urchins ◽  
Temperature Limit ◽  
Feeding Rates ◽  
Righting Response ◽  
Mesocentrotus Nudus ◽  
Temperature Rate ◽  
High Or Low Temperature

Ocean warming has facilitated the extension of Heliocidaris crassispina to Oga Peninsula, Japan, where the native species Mesocentrotus nudus has disappeared. To verify the temperature impacts on the physiology and behaviour of the two species, we reared small sea urchins at the increasing/decreasing temperature rate of 2.5°C week-1. The righting response, lantern reflex, gonad and gut carbon (C) and nitrogen (N) contents, and feeding rate were investigated. The high and low temperature limits of H. crassispina were 33.3°C and 3.9°C, respectively, which were higher than those of M. nudus. The optimal temperature ranges for behaviour and feeding in H. crassispina were 10.3–31.0°C and 10.3–33.4°C, respectively, which were higher than those in M. nudus. Feeding rates decreased significantly in both species when the temperature approached the high or low temperature limit, but the gut C and N contents of were not greatly affected. At 26–31°C, the feeding rate significantly decreased in M. nudus but not in H. crassispina, which may explain the replacement of M. nudus by H. crassispina in the Oga Peninsula.

Effects of Prey Abundance on the Development of the Spider Agelenopsis potteri (Blackwall) (Araneae: Agelenidae)

1965 ◽  
Vol 97 (2) ◽  
pp. 141-147 ◽  
Author(s):  
A. L. Turnbull
Keyword(s):  
Aedes Aegypti ◽  
Feeding Rate ◽  
Prey Capture ◽  
Prey Abundance ◽  
Feeding Rates ◽  
Live Prey ◽  
Straight Line ◽  
Line Relationship

AbstractAgelenopsis potteri (Blackwall) spiders that were reared from egg to adult on live prey (Aedes aegypti L.) supplied at different daily rates varied in the rate that they were able to capture prey, grow, and attain maturity. Mortality varied inversely with feeding rates, but some spiders matured at each feeding rate. All spiders matured in seven stages regardless of the rate of feeding. Both sexes were mature following the sixth moult. The rate of prey capture declined sharply in the adults. Males matured about four days sooner than females. A straight-line relationship exists between the rate at which prey were captured and the dry weights of the adult spiders. A straight-line relationship was also found between the numbers of prey captured per day and the daily development of the spider.

TiC Reinforced Steel Matrix Composite Layers Produced by Laser Surface Alloying

2008 ◽  
Vol 59 ◽  
pp. 55-61 ◽  
Author(s):  
A. Fernández-Vicente ◽  
G. Castro ◽  
J.L. Arias ◽  
Maria Angeles Montealegre
Keyword(s):  
Wear Resistance ◽  
Feeding Rate ◽  
Laser Surface ◽  
Beam Power ◽  
Powder Injection ◽  
Steel Matrix ◽  
Surface Alloying ◽  
Feeding Rates ◽  
Laser Surface Alloying ◽  
Powder Feeding

In the present work, laser surface alloying of H13 tool steel by using TiC has been performed by means of DHPDL (Direct high power diode laser). Different layers were produced by varying laser beam power and powder feeding rate. Several alloying degrees were obtained depending on the laser parameters employed. Laser surface alloyed layers were analyzed by using optical and scanning electron microscopy. Wear resistance was evaluated through pin-on-disk tests at room temperature. In general, it was observed that dilution of TiC powders into the molten H13 substrate decreased as the powder-feeding rate increased and particles size of the titanium carbide precipitates was larger for the higher feeding rates. Wear measurements showed lower values for the wear resistance coefficient of laser alloying layers produced at higher values of the powder injection (feeding) rate. Analysis of the wear surface track was conducted and the specific contribution of the microstructural features on the wear coefficient was assessed. Thus, it was found that larger particles sizes and particle contents protected the martensitic and dendritic steel matrix from being deeply worn. Lower TiC contents in the alloyed layer gave rise to a higher contribution of the plastic deformation in the wear track.

A Conceptual Model for the Estimation of the Sensitivity of Black Fly Larvae to Bacillus thuringiensis var. israelensis

1989 ◽  
Vol 46 (10) ◽  
pp. 1785-1792 ◽  
Author(s):  
Antoine Morin ◽  
Christian Back ◽  
Jacques Boisvert ◽  
Robert H. Peters
Keyword(s):  
Bacillus Thuringiensis ◽  
Feeding Rate ◽  
Standard Procedure ◽  
Dry Mass ◽  
Published Data ◽  
Contact Period ◽  
Larval Feeding ◽  
Feeding Rates ◽  
Black Fly ◽  
Proposed Model

Results from bioassays of a commercial formulation of Bacillus thuringiensis var. israelensis (Teknar HP-D) are combined with an empirical model of the feeding rate of larvae of a target species of black fly (Simulium venustum/verecundum) to develop a model relating the mortality of larvae to the amount of formulation ingested per unit mass of larvae (specific ingested dose). LD50 of Teknar HP-D was about 1 μg wet mass of Teknar per milligram dry mass of larvae, and independent of size of the larvae and seston concentration. Compared with standard assay analysis relating the mortality to the dose (milligrams per litre times seconds), the proposed model allowed more precise and replicable estimation of the effective dose. Reanalysis of published data on the potency of another Bti formulation (Teknar WDC), confirmed the superiority of the proposed model over the standard procedure. Susceptibility of larvae to particulate larvicides is mainly a function of the larval feeding rate. In addition to size of the larvae, temperature, and seston concentration, analysis of the model reveals that the length of the contact period and the variability of feeding rates among individual larvae are important factors determining the mortality rate following treatments.

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