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Sample records for mosquito retina implications

  1. Mosquito larval habitats and public health implications in Abeokuta ...

    The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette.

  2. Rift Valley fever virus-infected mosquito ova and associated pathology: possible implications for endemic maintenance

    Romoser WS

    2011-09-01

    hemocoel, RVFV-infected reproductive tissues were found, particularly follicular epithelia and oocyte/nurse cells. Ovarian infection from the hemocoel is a crucial step in establishing a vertically transmitting mosquito line. Ovarian follicles originate from germarial cells, primordia located distally in each ovariole, and infection of these cells is expected to be requisite for long-term vertical transmission. However, no germarial cell infection was found, so establishing a new line of vertically transmitting mosquitoes may require two generations. The findings support the hypothesis that Ae. mcintoshi is involved in the endemic maintenance of RVFV by vertical transmission. Detection of distinct pathology in infected eggs raises the possibility of virus-laden eggs being deposited among healthy eggs, thereby providing an exogenous source of infection via ingestion by mosquito larvae and other organisms. This has potentially significant epidemiological implications. Possible modes of entry of virus from the hemocoel into the ovaries and routes by which larvae might become infected by ingesting virus are discussed.Keywords: hemocoel, ovary, vertical transmission, Aedes mcintoshi, arbovirus, antigen positive

  3. The temporal spectrum of adult mosquito population fluctuations: conceptual and modeling implications.

    Yun Jian

    Full Text Available An improved understanding of mosquito population dynamics under natural environmental forcing requires adequate field observations spanning the full range of temporal scales over which mosquito abundance fluctuates in natural conditions. Here we analyze a 9-year daily time series of uninterrupted observations of adult mosquito abundance for multiple mosquito species in North Carolina to identify characteristic scales of temporal variability, the processes generating them, and the representativeness of observations at different sampling resolutions. We focus in particular on Aedes vexans and Culiseta melanura and, using a combination of spectral analysis and modeling, we find significant population fluctuations with characteristic periodicity between 2 days and several years. Population dynamical modelling suggests that the observed fast fluctuations scales (2 days-weeks are importantly affected by a varying mosquito activity in response to rapid changes in meteorological conditions, a process neglected in most representations of mosquito population dynamics. We further suggest that the range of time scales over which adult mosquito population variability takes place can be divided into three main parts. At small time scales (indicatively 2 days-1 month observed population fluctuations are mainly driven by behavioral responses to rapid changes in weather conditions. At intermediate scales (1 to several month environmentally-forced fluctuations in generation times, mortality rates, and density dependence determine the population characteristic response times. At longer scales (annual to multi-annual mosquito populations follow seasonal and inter-annual environmental changes. We conclude that observations of adult mosquito populations should be based on a sub-weekly sampling frequency and that predictive models of mosquito abundance must include behavioral dynamics to separate the effects of a varying mosquito activity from actual changes in the

  4. AAV-Mediated Clarin-1 Expression in the Mouse Retina: Implications for USH3A Gene Therapy.

    Astra Dinculescu

    Full Text Available Usher syndrome type III (USH3A is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1 gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder.

  5. AAV-Mediated Clarin-1 Expression in the Mouse Retina: Implications for USH3A Gene Therapy.

    Dinculescu, Astra; Stupay, Rachel M; Deng, Wen-Tao; Dyka, Frank M; Min, Seok-Hong; Boye, Sanford L; Chiodo, Vince A; Abrahan, Carolina E; Zhu, Ping; Li, Qiuhong; Strettoi, Enrica; Novelli, Elena; Nagel-Wolfrum, Kerstin; Wolfrum, Uwe; Smith, W Clay; Hauswirth, William W

    2016-01-01

    Usher syndrome type III (USH3A) is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1) gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder.

  6. Mosquito Control

    ... Labs and Research Centers Contact Us Share Mosquito Control About Mosquitoes General Information Life Cycle Information from ... Repellent that is Right for You DEET Mosquito Control Methods Success in mosquito control: an integrated approach ...

  7. A novel source of methylglyoxal and glyoxal in retina: implications for age-related macular degeneration.

    Yoon, Kee Dong; Yamamoto, Kazunori; Ueda, Keiko; Zhou, Jilin; Sparrow, Janet R

    2012-01-01

    Aging of retinal pigment epithelial (RPE) cells of the eye is marked by accumulations of bisretinoid fluorophores; two of the compounds within this lipofuscin mixture are A2E and all-trans-retinal dimer. These pigments are implicated in pathological mechanisms involved in some vision-threatening disorders including age-related macular degeneration (AMD). Studies have shown that bisretinoids are photosensitive compounds that undergo photooxidation and photodegradation when irradiated with short wavelength visible light. Utilizing ultra performance liquid chromatography (UPLC) with electrospray ionization mass spectrometry (ESI-MS) we demonstrate that photodegradation of A2E and all-trans-retinal dimer generates the dicarbonyls glyoxal (GO) and methylglyoxal (MG), that are known to modify proteins by advanced glycation endproduct (AGE) formation. By extracellular trapping with aminoguanidine, we established that these oxo-aldehydes are released from irradiated A2E-containing RPE cells. Enzyme-linked immunosorbant assays (ELISA) revealed that the substrate underlying A2E-containing RPE was AGE-modified after irradiation. This AGE deposition was suppressed by prior treatment of the cells with aminoguanidine. AGE-modification causes structural and functional impairment of proteins. In chronic diseases such as diabetes and atherosclerosis, MG and GO modify proteins by non-enzymatic glycation and oxidation reactions. AGE-modified proteins are also components of drusen, the sub-RPE deposits that confer increased risk of AMD onset. These results indicate that photodegraded RPE bisretinoid is likely to be a previously unknown source of MG and GO in the eye.

  8. Taking malaria transmission out of the bottle: implications of mosquito dispersal for vector-control interventions

    Killeen, G.F.; Knols, B.G.J.; Gu, W.D.

    2003-01-01

    Most malaria transmission models assume enclosed systems of people, parasites, and vectors in which neither emigration nor immigration of mosquitoes is considered. This simplification has facilitated insightful analyses but has substantial limitations for evaluating control measures in the field.

  9. The retina

    van Reyk, David M; Gillies, Mark C; Davies, Michael Jonathan

    2003-01-01

    A prominent and early feature of the retinopathy of diabetes mellitus is a diffuse increase in vascular permeability. As the disease develops, the development of frank macular oedema may result in vision loss. That reactive oxygen species production is likely to be elevated in the retina, and tha...

  10. Prey preferences of aquatic insects: potential implications for the regulation of wetland mosquitoes.

    Saha, N; Aditya, G; Saha, G K

    2014-03-01

    Wetlands are potential sites for mosquito breeding and are thus important in the context of public health. The use of chemical and microbial controls is constrained in wetlands in view of their potential impact on the diverse biota. Biological control using generalist aquatic insects can be effective, provided a preference for mosquito larvae is exhibited. The mosquito prey preferences of water bugs and larvae of odonate species were evaluated using chironomid larvae, fish fingerlings and tadpoles as alternative prey. Manly's selectivity (αi ) values with 95% confidence intervals (CIs) were estimated to judge prey preference patterns. Multivariate analysis of variance (manova) and standardized canonical coefficients were used to test the effects of density on prey selectivity. The αi values indicated a significant preference (P insect predators tested for mosquito larvae over the alternative prey as a density-dependent function. On a comparative scale, chironomid larvae had the highest impact as alternative prey. In a multiple-prey experiment, predators showed a similar pattern of preference for mosquito larvae over alternative prey, reflecting a significant (P insect predators can effectively reduce mosquito density in the presence of multiple alternative prey. © 2013 The Royal Entomological Society.

  11. Mosquito larval habitat mapping using remote sensing and GIS: Implications of coalbed methane development and West Nile virus

    Zou, L.; Miller, S.N.; Schmidtmann, E.T. [University of Wyoming, Laramie, WY (United States). Dept. of Renewable Resources

    2006-09-15

    Potential larval habitats of the mosquito Culex tarsalis (Coquillett), implicated as a primary vector of West Nile virus in Wyoming, were identified using integrated remote sensing and geographic information system (GIS) analyses. The study area is in the Powder River Basin of north central Wyoming, an area that has been undergoing a significant increase in coalbed methane gas extractions since the late 1990s. Large volumes of water are discharged, impounded, and released during the extraction of methane gas, creating aquatic habitats that have the potential to support immature mosquito development. Landsat TM and ETM + data were initially classified into spectrally distinct water and vegetation classes, which were in turn used to identify suitable larval habitat sites. This initial habitat classification was refined using knowledge-based GIS techniques requiring spatial data layers for topography, streams, and soils to reduce the potential for overestimation of habitat. Accuracy assessment was carried out using field data and high-resolution aerial photography commensurate with one of the Landsat images. The classifier can identify likely habitat for ponds larger than 0.8 ha (2 acres) with generally satisfactory results (72.1%) with a lower detection limit of approximate to 0.4 ha (1 acre). Results show a 75% increase in potential larval habitats from 1999 to 2004 in the study area, primarily because of the large increase in small coalbed methane water discharge ponds. These results may facilitate mosquito abatement programs in the Powder River Basin with the potential for application throughout the state and region.

  12. The Mosquito Melanization Response Is Implicated in Defense against the Entomopathogenic Fungus Beauveria bassiana

    Osta, Mike A.

    2012-01-01

    Mosquito immunity studies have focused mainly on characterizing immune effector mechanisms elicited against parasites, bacteria and more recently, viruses. However, those elicited against entomopathogenic fungi remain poorly understood, despite the ubiquitous nature of these microorganisms and their unique invasion route that bypasses the midgut epithelium, an important immune tissue and physical barrier. Here, we used the malaria vector Anopheles gambiae as a model to investigate the role of melanization, a potent immune effector mechanism of arthropods, in mosquito defense against the entomopathogenic fungus Beauveria bassiana, using in vivo functional genetic analysis and confocal microscopy. The temporal monitoring of fungal growth in mosquitoes injected with B. bassiana conidia showed that melanin eventually formed on all stages, including conidia, germ tubes and hyphae, except the single cell hyphal bodies. Nevertheless, melanin rarely aborted the growth of any of these stages and the mycelium continued growing despite being melanized. Silencing TEP1 and CLIPA8, key positive regulators of Plasmodium and bacterial melanization in A. gambiae, abolished completely melanin formation on hyphae but not on germinating conidia or germ tubes. The detection of a layer of hemocytes surrounding germinating conidia but not hyphae suggested that melanization of early fungal stages is cell-mediated while that of late stages is a humoral response dependent on TEP1 and CLIPA8. Microscopic analysis revealed specific association of TEP1 with surfaces of hyphae and the requirement of both, TEP1 and CLIPA8, for recruiting phenoloxidase to these surfaces. Finally, fungal proliferation was more rapid in TEP1 and CLIPA8 knockdown mosquitoes which exhibited increased sensitivity to natural B. bassiana infections than controls. In sum, the mosquito melanization response retards significantly B. bassiana growth and dissemination, a finding that may be exploited to design transgenic

  13. Relevant microclimate for determining the development rate of malaria mosquitoes and possible implications of climate change

    Paaijmans, K.P.; Imbahale, S.S.; Thomas, M.B.; Takken, W.

    2010-01-01

    Background The relationship between mosquito development and temperature is one of the keys to understanding the current and future dynamics and distribution of vector-borne diseases such as malaria. Many process-based models use mean air temperature to estimate larval development times, and hence

  14. Characterizing pollutant emissions from mosquito repellents incenses and implications in risk assessment of human health.

    Wang, Lina; Zheng, Xinran; Stevanovic, Svetlana; Xiang, Zhiyuan; Liu, Jing; Shi, Huiwen; Liu, Jing; Yu, Mingzhou; Zhu, Chun

    2018-01-01

    Mosquito-repellent incense is one of the most popular products used for dispelling mosquitos during summer in China. It releases large amounts of particulate and gaseous pollutants which constitute a potential hazard to human health. We conducted chamber experiment to characterize major pollutants from three types of mosquito-repellent incenses, further assessed the size-fractionated deposition in human respiratory system, and evaluated the indoor removing efficiency by fresh air. Results showed that the released pollutant concentrations were greater than permissible levels in regulations in GB3095-2012, as well as suggested by the World Health Organization (WHO). Formaldehyde accounted for 10-20% of the total amount of pollutants. Fine particles dominated in the total particulate concentrations. Geometric standard deviation (GSD) of particle number size distributions was in the range of 1.45-1.93. Count median diameter (CMD) ranged from 100 to 500 nm. Emission rates, burning rates and emission factors of both particulate and gaseous pollutants were compared and discussed. The deposition fractions in pulmonary airway from the disc solid types reached up to 52.7% of the total deposition, and the largest deposition appeared on juvenile group. Computational Fluid Dynamics (CFD) modellings indicated air-conditioner on and windows closed was the worst case. The highest concentration was 180-200 times over the standard limit. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Insect repellents and sunscreen: implications for personal protection strategies against mosquito-borne disease.

    Webb, Cameron E; Russell, Richard C

    2009-10-01

    To determine the protection times provided by insect repellent and sunscreen in combined formulations against biting mosquitoes. To determine if concurrent use of repellent and sunscreen influenced protection times. Insect repellent containing comparable concentrations of N, N-diethyl-3-methylbenzamide (DEET) with and without sunscreen were tested on human skin to determine the mean protection time (MPT) against Aedes aegypti (L.) in the laboratory. Further trials were undertaken to determine the effect on MPT of sunscreen reapplication over repellent every two hours. There was no significant difference in the MPT provided by 80% DEET with (MPT+/-SE=770+/-54.8 minutes) and without (MPT+/-SE=830+/-20.2 minutes) sunscreen or 7.14% DEET with (MPT+/-SE =240+/-15.5 minutes) and 6.98% DEET without (MPT+/-SE =230+/-18.4 minutes) sunscreen. Reapplication of sunscreen resulted in a significantly lower MPT of a 17.0% DEET formulation when sunscreen was reapplied concurrently (MPT+/-SE=330+/-25.2 minutes), compared with DEET alone (MPT+/-SE =400+/-12.7 minutes). When combined in a single formulation with sunscreen, the MPT provided by both high and low concentrations of DEET is not reduced. However, if sunscreen is reapplied over insect repellent, protection times can be reduced significantly. In areas of endemic mosquito-borne disease, the reapplication of a low concentration repellent and sunscreen formulation may provide the most effective protection from biting mosquitoes while minimising the risk of overexposure to DEET.

  16. Mitigating Mosquito Disease Vectors with Citizen Science: a Review of the GLOBE Observer Mosquito Habitat Mapper Pilot and Implications for Wide-scale Implementation

    Riebeek Kohl, H.; Low, R.; Boger, R. A.; Schwerin, T. G.; Janney, D. W.

    2017-12-01

    The spread of disease vectors, including mosquitoes, is an increasingly significant global environmental issue driven by a warming climate. In 2017, the GLOBE Observer Program launched a new citizen science initiative to map mosquito habitats using the free GLOBE Observer App for smart phones and tablets. The app guides people to identify mosquito larvae and breeding sites, and then once documented, to eliminate or treat the site to prevent further breeding. It also gives citizen scientists the option to identify the mosquito larvae species to determine whether it is one of three genera that potentially could transmit Zika, dengue fever, yellow fever, chikungunya, and other diseases. This data is uploaded to an international database that is freely available to the public and science community. GLOBE Observer piloted the initiative with educators in the United States, Brazil, and Peru, and it is now open for global participation. This presentation will discuss lessons learned in the pilot phase as well as plans to implement the initiative worldwide in partnership with science museums and science centers. GLOBE Observer is the non-student citizen science arm of the Global Learning and Observations to Benefit the Environment (GLOBE) Program, a long-standing, international science and education program that provides students and citizen scientists with the opportunity to participate in data collection and the scientific process, and contribute meaningfully to our understanding of the Earth system and global environment. GLOBE Observer data collection also includes cloud cover and cloud type and land cover/land use (in late 2017).

  17. Mosquito Bites

    ... virus to humans. Other mosquito-borne infections include yellow fever, malaria and some types of brain infection (encephalitis). ... certain diseases, such as West Nile virus, malaria, yellow fever and dengue fever. The mosquito obtains a virus ...

  18. Persistent oscillations and backward bifurcation in a malaria model with varying human and mosquito populations: implications for control.

    Ngonghala, Calistus N; Teboh-Ewungkem, Miranda I; Ngwa, Gideon A

    2015-06-01

    We derive and study a deterministic compartmental model for malaria transmission with varying human and mosquito populations. Our model considers disease-related deaths, asymptomatic immune humans who are also infectious, as well as mosquito demography, reproduction and feeding habits. Analysis of the model reveals the existence of a backward bifurcation and persistent limit cycles whose period and size is determined by two threshold parameters: the vectorial basic reproduction number Rm, and the disease basic reproduction number R0, whose size can be reduced by reducing Rm. We conclude that malaria dynamics are indeed oscillatory when the methodology of explicitly incorporating the mosquito's demography, feeding and reproductive patterns is considered in modeling the mosquito population dynamics. A sensitivity analysis reveals important control parameters that can affect the magnitudes of Rm and R0, threshold quantities to be taken into consideration when designing control strategies. Both Rm and the intrinsic period of oscillation are shown to be highly sensitive to the mosquito's birth constant λm and the mosquito's feeding success probability pw. Control of λm can be achieved by spraying, eliminating breeding sites or moving them away from human habitats, while pw can be controlled via the use of mosquito repellant and insecticide-treated bed-nets. The disease threshold parameter R0 is shown to be highly sensitive to pw, and the intrinsic period of oscillation is also sensitive to the rate at which reproducing mosquitoes return to breeding sites. A global sensitivity and uncertainty analysis reveals that the ability of the mosquito to reproduce and uncertainties in the estimations of the rates at which exposed humans become infectious and infectious humans recover from malaria are critical in generating uncertainties in the disease classes.

  19. Retina-Inspired Filter.

    Doutsi, Effrosyni; Fillatre, Lionel; Antonini, Marc; Gaulmin, Julien

    2018-07-01

    This paper introduces a novel filter, which is inspired by the human retina. The human retina consists of three different layers: the Outer Plexiform Layer (OPL), the inner plexiform layer, and the ganglionic layer. Our inspiration is the linear transform which takes place in the OPL and has been mathematically described by the neuroscientific model "virtual retina." This model is the cornerstone to derive the non-separable spatio-temporal OPL retina-inspired filter, briefly renamed retina-inspired filter, studied in this paper. This filter is connected to the dynamic behavior of the retina, which enables the retina to increase the sharpness of the visual stimulus during filtering before its transmission to the brain. We establish that this retina-inspired transform forms a group of spatio-temporal Weighted Difference of Gaussian (WDoG) filters when it is applied to a still image visible for a given time. We analyze the spatial frequency bandwidth of the retina-inspired filter with respect to time. It is shown that the WDoG spectrum varies from a lowpass filter to a bandpass filter. Therefore, while time increases, the retina-inspired filter enables to extract different kinds of information from the input image. Finally, we discuss the benefits of using the retina-inspired filter in image processing applications such as edge detection and compression.

  20. Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

    Christensen Bruce M

    2009-11-01

    Full Text Available Abstract Background The purpose of this study was to extend prior studies of molecular detection of Brugia malayi DNA in vector (Aedes aegypti- Liverpool and non-vector (Culex pipiens mosquitoes at different times after ingestion of infected blood. Results Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in Ae. aegypti- Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in Cx. pipiens, and these were not labeled by the antibody. Conclusion This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.

  1. Toxicological effects of prolonged and intense use of mosquito coil emission in rats and its implications on malaria control

    Emmanuel Taiwo Idowu

    2013-09-01

    Full Text Available Efectos toxicológicos del uso prolongado e intenso de emisiones de espirales contra mosquitos en ratas y sus implicaciones sobre el control de la malaria. Mosquito coil is a vector control option used to prevent malaria in low income counties, while some studies have addressed this issue, additional reseach is required to increase knowledge on the adverse health effects caused by the prolonged use of coils. In this study we investigated the toxicological effects of fumes from two locally manufactured mosquito coil insecticides (with pyrethroids: transfluthrin and d-allethrin as active ingredients on male albino rats. For this, we recorded the haematological and biochemical indices, and made histopathology and mutagenicity evaluations in rats exposed to mosquito fumes during 2, 4, 8, 12 and 16 week periods. Haematological determination was performed using automated hematology analyzer to determine White Blood Cell (WBC, Packed Cell Volume (PCV, Red Blood Cell (RBC and Platelet (PLT counts, while biochemical evaluations were determined using available commercial kits. Gross histopathological changes were studied for the kidney, liver and lungs in sacrificed rats. The rat sperm head abnormalities assessment was used to evaluate mutagenicity. Mosquito coil fumes produced significant increase (P0.05. Mutagenicity assessment revealed sperm abnormality was statistically significant (P<0.05 compared with the control at 8, 12 and 16 weeks post exposure to transfluthrin. Histological studies revealed severe lung damage evidenced by interstitial accumulations, pulmonary oedema and emphysema in exposed rats. Intracellular accumulations and severe sinusoidal congestion of liver cells were observed from 12 weeks exposure, indicating liver damage. Our studies indicate that mosquito coil fumes do initiate gradual damage to the host. These pathological effects must be taken into consideration by the malaria control program, particularly when regulating their

  2. Mosquito Bites

    ... weeks. Some female mosquitoes can hibernate in the winter, and they can live for months. What health ... gutters, buckets, pool covers, pet water dishes, discarded tires, or birdbaths. If you plan to travel, get ...

  3. Modified saponification and HPLC methods for analyzing carotenoids from the retina of quail: implications for its use as a nonprimate model species.

    Toomey, Matthew B; McGraw, Kevin J

    2007-09-01

    To investigate carotenoid content in the retina of Japanese quail (Coturnix japonica), for comparison with carotenoids in human retina, and to assess the effects of different saponification procedures on the recovery of quail retinal carotenoids. Extracted retinal carotenoids were saponified with methods adapted from recent studies, then identified and quantified with reverse-phase high-performance liquid chromatography (HPLC). To assess the effects of saponification conditions on carotenoid recovery from quail retina, we varied base concentration and the total time of saponification across a wide range and again used HPLC to compare carotenoid concentrations among conditions. Astaxanthin and galloxanthin were the dominant carotenoids recovered in the quail retina, along with smaller amounts of five other carotenoids (lutein, zeaxanthin, 3'-epilutein, epsilon-carotene, and an unidentified carotenoid). Astaxanthin was sensitive to saponification conditions; recovery was poor with strong bases (0.2 and 0.5 M KOH) and best with weak bases (0.01 and 0.2 M KOH). In contrast, xanthophyll carotenoids (galloxanthin, zeaxanthin, lutein, 3'-epilutein, and the unknown) were best recovered with strong base after 6 hours of saponification at room temperature. The recovery of epsilon-carotene was not affected by saponification conditions. Separate chemical hydrolysis procedures--using a strong base to recover xanthophylls and a weak base to recover astaxanthin--should be used for maximizing recovery of quail retinal carotenoids. Because the dominant carotenoids in quail retina are absent in human retina, and because of their different packaging (e.g., esterified in oil droplets) and light-absorbance properties compared with xanthophylls in the human eye, use of the quail as a model organism for studying human retinal carotenoids should be approached with caution.

  4. Desprendimiento de retina

    L. Jaime Claramunt, Dr.

    2010-11-01

    Full Text Available El desprendimiento de retina (DR consiste en la separación entre la retina neurosensorial y el epitelio pigmentario subyacente. Su forma más frecuente es el DR regmatógeno, causado por una rotura en la retina. Se manifiesta generalmente como un defecto en el campo visual o mala visión. Si se pesquisa y trata oportunamente tiene buenas posibilidades de éxito. No obstante, sigue siendo una causa importante de mala visión y ceguera, por lo que su prevención tiene un rol fundamental.

  5. Desprendimiento de retina

    L. Jaime Claramunt, Dr.

    2010-01-01

    El desprendimiento de retina (DR) consiste en la separación entre la retina neurosensorial y el epitelio pigmentario subyacente. Su forma más frecuente es el DR regmatógeno, causado por una rotura en la retina. Se manifiesta generalmente como un defecto en el campo visual o mala visión. Si se pesquisa y trata oportunamente tiene buenas posibilidades de éxito. No obstante, sigue siendo una causa importante de mala visión y ceguera, por lo que su prevención tiene un rol fundamental.

  6. Roles for the ubiquitin-proteasome pathway in protein quality control and signaling in the retina: implications in the pathogenesis of age-related macular degeneration

    The accumulation of damaged or postsynthetically modified proteins and dysregulation of inflammatory responses and angiogenesis in the retina/RPE are thought be etiologically related to formation of drusen and choroidal neovascularization (CNV), hallmarks of age-related macular degeneration (AMD). T...

  7. A programmable artificial retina

    Bernard, T.M.; Zavidovique, B.Y.; Devos, F.J.

    1993-01-01

    An artificial retina is a device that intimately associates an imager with processing facilities on a monolithic circuit. Yet, except for simple environments and applications, analog hardware will not suffice to process and compact the raw image flow from the photosensitive array. To solve this output problem, an on-chip array of bare Boolean processors with halftoning facilities might be used, providing versatility from programmability. By setting the pixel memory size to 3 b, the authors have demonstrated both the technological practicality and the computational efficiency of this programmable Boolean retina concept. Using semi-static shifting structures together with some interaction circuitry, a minimal retina Boolean processor can be built with less than 30 transistors and controlled by as few as 6 global clock signals. The successful design, integration, and test of such a 65x76 Boolean retina on a 50-mm 2 CMOS 2-μm circuit are presented

  8. Helping the Retina Regenerate

    ... the retina News Brief 03/30/17 A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored ...

  9. Effect of Deforestation and Land Use Changes on Mosquito Productivity and Development in Western Kenya Highlands: Implication for Malaria Risk.

    Kweka, Eliningaya J; Kimaro, Epiphania E; Munga, Stephen

    2016-01-01

    African highlands were known to be free of malaria for the past 50 years. However, the ever growing human population in the highlands of Africa has led to the deforestation and land coverage changes to create space for more land for cultivation, grazing, and house construction materials needs. This has lead to the creation of suitable breeding habitats, which are in open places. Decrease of canopy and forest cover has led to increased temperature both in outdoors and indoors in deforested areas. This increased temperature has resulted in the shortening of developmental stages of aquatic stages of mosquitoes and sporogony development in adult mosquitoes. Assessment of the effects of deforestation and land coverage changes (decrease), which leads to temperature changes and subsequently increases survivorship of adults and sporogony development in adult mosquitoes' body was gathered from previous data collected from 2003 to 2012 using different analysis techniques. Habitats productivity, species dynamics and abundance, mosquitoes feeding rates, and sporogony development are presented in relation to temperature changes. The effects of temperature rise due to land cover changes in highlands of western Kenya on larval developmental rates, adult sporogony developments, and malaria risk in human population were derived. Vector species dynamics and abundance in relation to land use changes have been found to change with time. This study found that, land cover changes is a key driver for the temperature rise in African highlands and increases the rate of malaria vectors Anopheles gambiae ssp., An. Funestus , and An. arabiensis colonizing the highlands. It has also significantly enhanced sporogony development rate and adult vector survival and therefore the risk of malaria transmission in the highlands.

  10. Interactions between Asaia, Plasmodium and Anopheles: new insights into mosquito symbiosis and implications in malaria symbiotic control.

    Capone, Aida; Ricci, Irene; Damiani, Claudia; Mosca, Michela; Rossi, Paolo; Scuppa, Patrizia; Crotti, Elena; Epis, Sara; Angeletti, Mauro; Valzano, Matteo; Sacchi, Luciano; Bandi, Claudio; Daffonchio, Daniele; Mandrioli, Mauro; Favia, Guido

    2013-06-18

    Malaria represents one of the most devastating infectious diseases. The lack of an effective vaccine and the emergence of drug resistance make necessary the development of new effective control methods. The recent identification of bacteria of the genus Asaia, associated with larvae and adults of malaria vectors, designates them as suitable candidates for malaria paratransgenic control.To better characterize the interactions between Asaia, Plasmodium and the mosquito immune system we performed an integrated experimental approach. Quantitative PCR analysis of the amount of native Asaia was performed on individual Anopheles stephensi specimens. Mosquito infection was carried out with the strain PbGFPCON and the number of parasites in the midgut was counted by fluorescent microscopy.The colonisation of infected mosquitoes was achieved using GFP or DsRed tagged-Asaia strains.Reverse transcriptase-PCR analysis, growth and phagocytosis tests were performed using An. stephensi and Drosophila melanogaster haemocyte cultures and DsRed tagged-Asaia and Escherichia coli strains. Using quantitative PCR we have quantified the relative amount of Asaia in infected and uninfected mosquitoes, showing that the parasite does not interfere with bacterial blooming. The correlation curves have confirmed the active replication of Asaia, while at the same time, the intense decrease of the parasite.The 'in vitro' immunological studies have shown that Asaia induces the expression of antimicrobial peptides, however, the growth curves in conditioned medium as well as a phagocytosis test, indicated that the bacterium is not an immune-target.Using fluorescent strains of Asaia and Plasmodium we defined their co-localisation in the mosquito midgut and salivary glands. We have provided important information about the relationship of Asaia with both Plasmodium and Anopheles. First, physiological changes in the midgut following an infected or uninfected blood meal do not negatively affect the

  11. Taurine uptake by human retinal pigment epithelium: implications for the transport of small solutes between the choroid and the outer retina.

    Hillenkamp, Jost; Hussain, Ali A; Jackson, Timothy L; Cunningham, Joanna R; Marshall, John

    2004-12-01

    To characterize the Michaelis-Menten kinetics of the taurine transporter (TT) in retinal pigment epithelium (RPE) freshly isolated from human donor eyes. To identify the rate limiting compartment in the pathway of taurine delivery from the choroidal blood supply to the outer retina composed by Bruch's-choroid (BC) and the RPE in the human older age group. In human donor samples (4 melanoma-affected eyes, and 14 control eyes; age range, 62-93 years), radiochemical techniques were used to determine the RPE taurine accumulation at various exogenous concentrations. The transport capability of human RPE was obtained from a kinetic analysis of the high-affinity carrier over a substrate concentration of 1 to 60 microM taurine. Uptake of taurine into human RPE at a taurine concentration of 1 microM was independent of donor age (P > 0.05) and averaged at 2.83 +/- 0.27 (SEM) pmol/10 minutes per 6-mm trephine. Taurine transport by human RPE was mediated by a high-affinity carrier of K(m) 50 microM and V(max) of 267 pmol/10 minutes per 5-mm disc. In human donor RPE, uptake of taurine remained viable in the age range 62 to 93 years. Taurine transport rates in the RPE were lower than across the isolated BC complex, and thus the data suggest that the former compartment houses the rate-limiting step in the delivery of taurine to the outer retina.

  12. A decade of colonization: the spread of the Asian tiger mosquito in Pennsylvania and implications for disease risk.

    Taber, Eric D; Hutchinson, Michael L; Smithwick, Erica A H; Blanford, Justine I

    2017-06-01

    In recent decades, the Asian tiger mosquito expanded its geographic range throughout the northeastern United States, including Pennsylvania. The establishment of Aedes albopictus in novel areas raises significant public health concerns, since this species is a highly competent vector of several arboviruses, including chikungunya, West Nile, and dengue. In this study, we used geographic information systems (GIS) to examine a decade of colonization by Ae. albopictus throughout Pennsylvania between 2001 and 2010. We examined the spatial and temporal distribution of Ae. albopictus using spatial statistical analysis and examined the risk of dengue virus transmission using a model that captures the probability of transmission. Our findings show that since 2001, the Ae. albopictus population in Pennsylvania has increased, becoming established and expanding in range throughout much of the state. Since 2010, imported cases of dengue fever have been recorded in Pennsylvania. Imported cases of dengue, in combination with summer temperatures conducive for virus transmission, raise the risk of local disease transmission. © 2017 The Society for Vector Ecology.

  13. Selective retina therapy (SRT)

    Brinkmann, R.; Birngruber, R.

    2007-01-01

    Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

  14. The infrared retina

    Krishna, Sanjay

    2009-01-01

    As infrared imaging systems have evolved from the first generation of linear devices to the second generation of small format staring arrays to the present 'third-gen' systems, there is an increased emphasis on large area focal plane arrays (FPAs) with multicolour operation and higher operating temperature. In this paper, we discuss how one needs to develop an increased functionality at the pixel level for these next generation FPAs. This functionality could manifest itself as spectral, polarization, phase or dynamic range signatures that could extract more information from a given scene. This leads to the concept of an infrared retina, which is an array that works similarly to the human eye that has a 'single' FPA but multiple cones, which are photoreceptor cells in the retina of the eye that enable the perception of colour. These cones are then coupled with powerful signal processing techniques that allow us to process colour information from a scene, even with a limited basis of colour cones. Unlike present day multi or hyperspectral systems, which are bulky and expensive, the idea would be to build a poor man's 'infrared colour' camera. We use examples such as plasmonic tailoring of the resonance or bias dependent dynamic tuning based on quantum confined Stark effect or incorporation of avalanche gain to achieve embodiments of the infrared retina.

  15. Controlling Mosquitoes Outside

    Mosquitoes can carry viruses, like West Nile, Zika, dengue, and chikungunya. In this podcast, Mr. Hubbard will teach you and his neighbor, Laura, ways to help reduce the number of mosquitoes outside your home. Tips include eliminating areas of standing water where mosquitoes lay eggs and using larvicides to kill young mosquitoes.

  16. Blood Meal Analysis of and Virus Detection in Mosquitoes Collected during a Rift Valley fever Epizootic/Epidemic: Implications for epidemic disease transmission dynamics

    Rift Valley fever (RVF) is a zoonosis of domestic ruminants in Africa. Bloodfed mosquitoes collected during the 2006-2007 RVF outbreak in Kenya were analyzed to determine the virus infection status and animal source of the bloodmeals. Bloodmeals from individual mosquito abdomens were screened for v...

  17. Molecular identification of host feeding patterns of snow-melt mosquitoes (Diptera: Culicidae): potential implications for the transmission ecology of Jamestown Canyon virus.

    Murdock, C C; Olival, Kevin J; Perkins, Susan L

    2010-03-01

    We collected blood-fed, snow-melt mosquitoes (Culicidae: Culiseta and Aedes) to describe the feeding patterns of potential mosquito vectors of Jamestown Canyon virus (JCV, Bunyaviridae: Orthobunyavirus). JCV is an arthropod-borne, zoonotic virus with deer as the primary amplifying host in western alpine ecosystems. We collected mosquitoes from natural resting areas, fiber pots, and carbon-dioxide baited miniature light traps in the Colorado Rocky Mountains in 2007. We conducted two polymerase chain reactions to amplify and sequence vertebrate DNA extracted from blood-fed mosquitoes, which yielded comparable, but not identical, results. Mammal-specific primers found mule deer (Odocoileus hemionus) and elk (Cervus elaphus canadensis) as the source of all bloodmeals. To determine if unamplified bloodmeals were from nonmammalian sources, we screened all samples with conserved vertebrate primers, which confirmed the initial polymerase chain reaction results, but also found porcupine (Erethizon dorsatum) and human (Homo sapiens) as additional bloodmeal sources. We consistently found that mule deer were the primary hosts for mosquitoes in this system. These results suggest that snow-melt mosquitoes, in particular A. cataphylla, may be important vectors in western JCV alpine systems and may also act as a bridge vector for JCV from cervid virus reservoirs to humans.

  18. The Retina Algorithm

    CERN. Geneva; PUNZI, Giovanni

    2015-01-01

    Charge particle reconstruction is one of the most demanding computational tasks found in HEP, and it becomes increasingly important to perform it in real time. We envision that HEP would greatly benefit from achieving a long-term goal of making track reconstruction happen transparently as part of the detector readout ("detector-embedded tracking"). We describe here a track-reconstruction approach based on a massively parallel pattern-recognition algorithm, inspired by studies of the processing of visual images by the brain as it happens in nature ('RETINA algorithm'). It turns out that high-quality tracking in large HEP detectors is possible with very small latencies, when this algorithm is implemented in specialized processors, based on current state-of-the-art, high-speed/high-bandwidth digital devices.

  19. Controlling Mosquitoes Outside

    2016-08-09

    Mosquitoes can carry viruses, like West Nile, Zika, dengue, and chikungunya. In this podcast, Mr. Hubbard will teach you and his neighbor, Laura, ways to help reduce the number of mosquitoes outside your home. Tips include eliminating areas of standing water where mosquitoes lay eggs and using larvicides to kill young mosquitoes.  Created: 8/9/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/9/2016.

  20. Corpus vitreum, retina og chorioidea biopsi

    Scherfig, Erik Christian Høegh

    2002-01-01

    oftalmology, biopsy, choroid, corpus vitreum, retina, malignant melanoma, biopsy technic, retinoblastoma......oftalmology, biopsy, choroid, corpus vitreum, retina, malignant melanoma, biopsy technic, retinoblastoma...

  1. Mosquito Life Cycle

    Knowing the stages of the mosquito's life will help you prevent mosquitoes around your home and help you choose the right pesticides for your needs, if you decide to use them. All mosquito species go through four distinct stages during their live cycle.

  2. The Neural Retina in Retinopathy of Prematurity

    Hansen, Ronald M.; Moskowitz, Anne; Akula, James D.; Fulton, Anne B.

    2016-01-01

    Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP. PMID:27671171

  3. Artificial Diets for Mosquitoes

    Kristina K. Gonzales

    2016-12-01

    Full Text Available Mosquito-borne diseases are responsible for more than a million human deaths every year. Modern mosquito control strategies such as sterile insect technique (SIT, release of insects carrying a dominant lethal (RIDL, population replacement strategies (PR, and Wolbachia-based strategies require the rearing of large numbers of mosquitoes in culture for continuous release over an extended period of time. Anautogenous mosquitoes require essential nutrients for egg production, which they obtain through the acquisition and digestion of a protein-rich blood meal. Therefore, mosquito mass production in laboratories and other facilities relies on vertebrate blood from live animal hosts. However, vertebrate blood is expensive to acquire and hard to store for longer times especially under field conditions. This review discusses older and recent studies that were aimed at the development of artificial diets for mosquitoes in order to replace vertebrate blood.

  4. Exotic mosquito threats require strategic surveillance and response planning.

    Webb, Cameron E; Doggett, Stephen L

    2016-12-14

    Mosquito-borne diseases caused by endemic pathogens such as Ross River, Barmah Forest and Murray Valley encephalitis viruses are an annual concern in New South Wales (NSW), Australia. More than a dozen mosquito species have been implicated in the transmission of these pathogens, with each mosquito occupying a specialised ecological niche that influences their habitat associations, host feeding preferences and the environmental drivers of their abundance. The NSW Arbovirus Surveillance and Mosquito Monitoring Program provides an early warning system for potential outbreaks of mosquito-borne disease by tracking annual activity of these mosquitoes and their associated pathogens. Although the program will effectively track changes in local mosquito populations that may increase with a changing climate, urbanisation and wetland rehabilitation, it will be less effective with current surveillance methodologies at detecting or monitoring changes in exotic mosquito threats, where different surveillance strategies need to be used. Exotic container-inhabiting mosquitoes such as Aedes aegypti and Ae. albopictus pose a threat to NSW because they are nuisance-biting pests and vectors of pathogens such as dengue, chikungunya and Zika viruses. International movement of humans and their belongings have spread these mosquitoes to many regions of the world. In recent years, these two mosquitoes have been detected by the Australian Government Department of Agriculture and Water Resources at local airports and seaports. To target the detection of these exotic mosquitoes, new trapping technologies and networks of surveillance locations are required. Additionally, incursions of these mosquitoes into urban areas of the state will require strategic responses to minimise substantial public health and economic burdens to local communities.

  5. Imaging of the peripheral retina

    Marcus Kernt

    2013-01-01

    Full Text Available The technical progress of the recent years has revolutionized imaging in ophthalmology. Scanning laser ophthalmoscopy (SLO, digital angiography, optical coherence tomography (OCT, and detection of fundus autofluorescence (FAF have fundamentally changed our understanding of numerous retinal and choroidal diseases. Besides the tremendous advances in macular diagnostics, there is more and more evidence that central pathologies are often directly linked to changes in the peripheral retina. This review provides a brief overview on current posterior segment imaging techniques with a special focus on the peripheral retina.

  6. Controlling Mosquitoes Indoors

    2016-08-23

    Mosquitoes can carry viruses, like West Nile and Zika. In this podcast, Mr. Hubbard teaches his neighbors, the Smith family, ways to help reduce the number of mosquitoes inside their home.  Created: 8/23/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/23/2016.

  7. Selective retina therapy (SRT); Selektive Retina-Therapie (SRT)

    Brinkmann, R.; Birngruber, R. [Luebeck Univ. (Germany). Inst. fuer Biomedizinische Optik; Medizinisches Laserzentrum Luebeck GmbH, Luebeck (Germany)

    2007-07-01

    Selective Retina Therapy (SRT) is a new and very gentle laser method developed at the Medical Laser Center Luebeck. It is currently investigated clinically in order to treat retinal disorders associated with a decreased function of the retinal pigment epithelium (RPE). SRT is designed to selectively effect the RPE while sparing the neural retina and the photoreceptors as well as the choroid. Aim of the therapy is the rejuvenation of the RPE in the treated areas, which should ideally lead to a long term metabolic increase at the chorio-retinal junction. In contrast to conventional laser photocoagulation, which is associated with a complete thermal necrosis of the treated site, SRT completely retains full vision. This paper reviews the methods and mechanisms behind selective RPE effects and reports the first clinical results. An online dosimetry technique to visualize the ophthalmoscopically invisible effects is introduced. (orig.)

  8. Avoid Mosquito Bites

    ... visiting CDC Travelers’ Health website . Pack a travel health kit . Remember to pack insect repellent and use it as directed to prevent mosquito bites. See a healthcare provider familiar with travel medicine, ideally 4 to 6 weeks ...

  9. Mosquito inspired medical needles

    Lenau, Torben Anker; Hesselberg, Thomas; Drakidis, Alexandros Dimitrios

    2017-01-01

    The stinging proboscis in mosquitos have diameters of only 40-100 μm which is much less than the thinnest medical needles and the mechanics of these natural stinging mechanisms have therefore attracted attention amongst developers of injection devises. The mosquito use a range of different...... strategies to lower the required penetration force hence allowing a thinner and less stiff proboscis structure. Earlier studies of the mosquito proboscis insertion strategies have shown how each of the single strategies reduces the required penetration force. The present paper gives an overview...... of the advanced set of mechanisms that allow the mosquito to penetrate human skin and also presents other biological mechanisms that facilitate skin penetration. Results from experiments in a skin mimic using biomimetic equivalents to the natural mechanisms are presented. This includes skin stretching, insertion...

  10. Mosquitoes of Middle America.

    1976-09-30

    data on bionomics and disease relations. 0. P. Forattini’s treatment of the Culicidae in “ Entomologia Medica” (Sao Paulo , Faculdade de Higiene e Saude...Canal Zone and U.S.A. Casal. Osvaldo H., Depart amento de Entomologia Sanitaria , Instituto de Microbio logi a, Buenos Aires, Argen tina.— Mosquitoes...976 17 Garcia , M iguel, Departamento de Entomologia Sanitaria , Instituto de Microbiologia , Buenos Aires, Argentina . — Mosquitoes from Argentina

  11. Towards photovoltaic powered artificial retina

    Santiago Silvestre

    2011-11-01

    Full Text Available The aim of this article is to provide an overview of current and future concepts in the field of retinal prostheses, and is focused on the power supply based on solar energy conversion; we introduce the possibility of using PV minimodules as power supply for a new concept of retinal prostheses: Photovoltaic Powered Artificial Retina (PVAR. Main characteristics of these PV modules are presented showing its potential for this application.

  12. Tips to Prevent Mosquito Bites

    ... discourage mosquitoes, ticks and other biting insects from landing on you. Here are tips for other preventive ... CDC Mosquito Control Methods - NPIC Exit Top of Page Contact Us to ask a question, provide feedback, ...

  13. Repelling mosquitoes with essential oils

    Riley, L.

    2017-12-01

    Mosquitoes carry diseases than can lead to serious illness and death. According to the World Health Organization, mosquitoes infect over 300 million people a year with Malaria and Dengue Fever, two life threatening diseases vectored by mosquitoes. Although insecticides are the most effective way to control mosquitoes, they are not always environmentally friendly. Therefore, alternative tactics should be considered. In this study, we looked at the repellency of various essential oils on female Aedes aegypti through a series of laboratory assays.

  14. [Lattice degeneration of the retina].

    Boĭko, E V; Suetov, A A; Mal'tsev, D S

    2014-01-01

    Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.

  15. Lattice degeneration of the retina.

    Byer, N E

    1979-01-01

    Lattice degeneration of the retina is the most important of all clinically distinct entities that effect the peripheral fundus and are related to retinal detachment. The purpose of this review is to survey the extensive literature, to evaluate the many diverse opinions on this subject, and to correlate and summarize all the known facts regarding this disease entity. The disease is fully defined and described, both clinically and histologically. Some aspects of the disease are still poorly understood, and some remain controversial, especially in the area of management. For this reason, the indications for treatment are discussed under eight subsections, with a view toward providing practical guidelines for recommendations in management.

  16. Flavivirus-Mosquito Interactions

    Yan-Jang S. Huang

    2014-11-01

    Full Text Available The Flavivirus genus is in the family Flaviviridae and is comprised of more than 70 viruses. These viruses have a broad geographic range, circulating on every continent except Antarctica. Mosquito-borne flaviviruses, such as yellow fever virus, dengue virus serotypes 1–4, Japanese encephalitis virus, and West Nile virus are responsible for significant human morbidity and mortality in affected regions. This review focuses on what is known about flavivirus-mosquito interactions and presents key data collected from the field and laboratory-based molecular and ultrastructural evaluations.

  17. Mosquito Bites are Bad!

    2016-08-11

    In this podcast for kids, the Kidtastics talk about the dangers of mosquito bites and how to prevent getting them.  Created: 8/11/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/11/2016.

  18. Play the Mosquito Game

    ... and Work Teachers' Questionnaire Malaria Play the Mosquito Game Play the Parasite Game About the games Malaria is one of the world's most common ... last will in Paris. Play the Blood Typing Game Try to save some patients and learn about ...

  19. Cacipacore virus as an emergent mosquito-borne Flavivirus

    Mario Luis Garcia de Figueiredo

    Full Text Available Abstract INTRODUCTION: Cacipacore virus (CPCV, a possible bird-associated flavivirus, has yet to be detected in mosquitoes. Our purpose is examining CPCV in mosquitoes from the Amazon region of Brazil. METHODS: Approximately 3,253 Culicidae (grouped into 264 pools were collected from the Amazon region during 2002-2006 and analyzed using a Flavivirus genus-specific reverse transcription- polymerase chain reaction followed by nested polymerase chain reaction assay and by nucleotide sequencing of amplicons. RESULTS: Nucleotide sequences from five mosquito samples showed high similarity to the those of CPCV originally isolated in the Amazon region. CONCLUSIONS: This is the first report of CPCV-infected mosquitoes which has implications on the arbovirus maintenance in nature and transmission to man.

  20. Acetylcholine receptors in the human retina

    Hutchins, J.B.; Hollyfield, J.G.

    1985-01-01

    Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand 3 H-propylbenzilylcholine mustard ( 3 H-PrBCM) to label muscarinic receptors. 3 H- or 125 I-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic receptors are apparently present in the inner plexiform layer of the retina. Autoradiographic grain densities are reduced in the presence of saturating concentrations of atropine, quinuclidinyl benzilate or scopolamine; this indicates that 3 H-PrBCM binding is specific for a population of muscarinic receptors in the human retina. Binding sites for radiolabeled alpha-BTx are found predominantly in the inner plexiform layer of the retina. Grain densities are reduced in the presence of d-tubocurarine, indicating that alpha-BTx may bind to a pharmacologically relevant nicotinic ACh receptor. This study provides evidence for cholinergic neurotransmission in the human retina

  1. Cytogenesis in the monkey retina

    La Vail, M.M.; Rapaport, D.H.; Rakic, P.

    1991-01-01

    Time of cell origin in the retina of the rhesus monkey (Macaca mulatta) was studied by plotting the number of heavily radiolabeled nuclei in autoradiograms prepared from 2- to 6-month-old animals, each of which was exposed to a pulse of 3H-thymidine (3H-TdR) on a single embryonic (E) or postnatal (P) day. Cell birth in the monkey retina begins just after E27, and approximately 96% of cells are generated by E120. The remaining cells are produced during the last (approximately 45) prenatal days and into the first several weeks after birth. Cell genesis begins near the fovea, and proceeds towards the periphery. Cell division largely ceases in the foveal and perifoveal regions by E56. Despite extensive overlap, a class-specific sequence of cell birth was observed. Ganglion and horizontal cells, which are born first, have largely congruent periods of cell genesis with the peak between E38 and E43, and termination around E70. The first labeled cones were apparent by E33, and their highest density was achieved between E43 and E56, tapering to low values at E70, although some cones are generated in the far periphery as late as E110. Amacrine cells are next in the cell birth sequence and begin genesis at E43, reach a peak production between E56 and E85, and cease by E110. Bipolar cell birth begins at the same time as amacrines, but appears to be separate from them temporally since their production reaches a peak between E56 and E102, and persists beyond the day of birth. Mueller cells and rod photoreceptors, which begin to be generated at E45, achieve a peak, and decrease in density at the same time as bipolar cells, but continue genesis at low density on the day of birth. Thus, bipolar, Mueller, and rod cells have a similar time of origin

  2. The ciliary margin zone of the mammalian retina generates retinal ganglion cells

    Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

    2016-01-01

    Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

  3. Complex computation in the retina

    Deshmukh, Nikhil Rajiv

    Elucidating the general principles of computation in neural circuits is a difficult problem requiring both a tractable model circuit as well as sophisticated measurement tools. This thesis advances our understanding of complex computation in the salamander retina and its underlying circuitry and furthers the development of advanced tools to enable detailed study of neural circuits. The retina provides an ideal model system for neural circuits in general because it is capable of producing complex representations of the visual scene, and both its inputs and outputs are accessible to the experimenter. Chapter 2 describes the biophysical mechanisms that give rise to the omitted stimulus response in retinal ganglion cells described in Schwartz et al., (2007) and Schwartz and Berry, (2008). The extra response to omitted flashes is generated at the input to bipolar cells, and is separable from the characteristic latency shift of the OSR apparent in ganglion cells, which must occur downstream in the circuit. Chapter 3 characterizes the nonlinearities at the first synapse of the ON pathway in response to high contrast flashes and develops a phenomenological model that captures the effect of synaptic activation and intracellular signaling dynamics on flash responses. This work is the first attempt to model the dynamics of the poorly characterized mGluR6 transduction cascade unique to ON bipolar cells, and explains the second lobe of the biphasic flash response. Complementary to the study of neural circuits, recent advances in wafer-scale photolithography have made possible new devices to measure the electrical and mechanical properties of neurons. Chapter 4 reports a novel piezoelectric sensor that facilitates the simultaneous measurement of electrical and mechanical signals in neural tissue. This technology could reveal the relationship between the electrical activity of neurons and their local mechanical environment, which is critical to the study of mechanoreceptors

  4. Non-Genetic Determinants of Mosquito Competence for Malaria Parasites

    Lefèvre, Thierry; Vantaux, Amélie; Dabiré, Kounbobr R.; Mouline, Karine; Cohuet, Anna

    2013-01-01

    Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies revealing a great diversity of ways in which non-genetic factors can interfere with mosquito-Plasmodium interactions. Here, we review the current evidence for such environmentally mediated effects, including ambient temperature, mosquito diet, microbial gut flora, and infection history, and we identify additional factors previously overlooked in mosquito-Plasmodium interactions. We also discuss epidemiological implications, and the evolutionary consequences for vector immunity and parasite transmission strategies. Finally, we propose directions for further research and argue that an improved knowledge of non-genetic influences on mosquito-Plasmodium interactions could aid in implementing conventional malaria control measures and contribute to the design of novel strategies. PMID:23818841

  5. Non-genetic determinants of mosquito competence for malaria parasites.

    Thierry Lefèvre

    Full Text Available Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies revealing a great diversity of ways in which non-genetic factors can interfere with mosquito-Plasmodium interactions. Here, we review the current evidence for such environmentally mediated effects, including ambient temperature, mosquito diet, microbial gut flora, and infection history, and we identify additional factors previously overlooked in mosquito-Plasmodium interactions. We also discuss epidemiological implications, and the evolutionary consequences for vector immunity and parasite transmission strategies. Finally, we propose directions for further research and argue that an improved knowledge of non-genetic influences on mosquito-Plasmodium interactions could aid in implementing conventional malaria control measures and contribute to the design of novel strategies.

  6. An analog silicon retina with multichip configuration.

    Kameda, Seiji; Yagi, Tetsuya

    2006-01-01

    The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study [1]. The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.

  7. Mosquito Control: Do Your Part

    Everyone can do their part to help control mosquitoes that can carry viruses like West Nile, Zika, dengue and chikungunya. In each episode of this podcast, you will learn ways to help reduce the number of mosquitoes in and around your home.

  8. Mosquito-host interactions during and after an outbreak of equine viral encephalitis in Eastern Panama.

    Wayra G Navia-Gine

    Full Text Available Mosquito blood meals provide information about the feeding habits and host preference of potential arthropod-borne disease vectors. Although mosquito-borne diseases are ubiquitous in the Neotropics, few studies in this region have assessed patterns of mosquito-host interactions, especially during actual disease outbreaks. Based on collections made during and after an outbreak of equine viral encephalitis, we identified the source of 338 blood meals from 10 species of mosquitoes from Aruza Abajo, a location in Darien province in eastern Panama. A PCR based method targeting three distinct mitochondrial targets and subsequent DNA sequencing was used in an effort to delineate vector-host relationships. At Aruza Abajo, large domesticated mammals dominated the assemblage of mosquito blood meals while wild bird and mammal species represented only a small portion of the blood meal pool. Most mosquito species fed on a variety of hosts; foraging index analysis indicates that eight of nine mosquito species utilize hosts at similar proportions while a stochastic model suggests dietary overlap among species was greater than would be expected by chance. The results from our null-model analysis of mosquito diet overlap are consistent with the hypothesis that in landscapes where large domestic animals dominate the local biomass, many mosquito species show little host specificity, and feed upon hosts in proportion to their biomass, which may have implications for the role of livestocking patterns in vector-borne disease ecology.

  9. Radioadaptive Cytoprotective Pathways in the Mouse Retina

    Zanello, Susana B.; Wotring, V.; Theriot, C.; Ploutz-Snyder, R.; Zhang, Y.; Wu, H.

    2010-01-01

    Exposure to cosmic radiation implies a risk of tissue degeneration. Radiation retinopathy is a complication of radiotherapy and exhibits common features with other retinopathies and neuropathies. Exposure to a low radiation dose elicits protective cellular events (radioadaptive response), reducing the stress of a subsequent higher dose. To assess the risk of radiation-induced retinal changes and the extent to which a small priming dose reduces this risk, we used a mouse model exposed to a source of Cs-137-gamma radiation. Gene expression profiling of retinas from non-irradiated control C57BL/6J mice (C) were compared to retinas from mice treated with a low 50 mGy dose (LD), a high 6 Gy dose (HD), and a combined treatment of 50 mGy (priming) and 6 Gy (challenge) doses (LHD). Whole retina RNA was isolated and expression analysis for selected genes performed by RTqPCR. Relevant target genes associated with cell death/survival, oxidative stress, cellular stress response and inflammation pathways, were analyzed. Cellular stress response genes were upregulated at 4 hr after the challenge dose in LHD retinas (Sirt1: 1.5 fold, Hsf1: 1.7 fold, Hspa1a: 2.5 fold; Hif1a: 1.8 fold, Bag1: 1.7). A similar trend was observed in LD animals. Most antioxidant enzymes (Hmox1, Sod2, Prdx1, Cygb, Cat1) and inflammatory mediators (NF B, Ptgs2 and Tgfb1) were upregulated in LHD and LD retinas. Expression of the pro-survival gene Bcl2 was upregulated in LD (6-fold) and LHD (4-fold) retinas. In conclusion, cytoprotective gene networks activation in the retina suggests a radioadaptive response to a priming irradiation dose, with mitigation of the deleterious effects of a subsequent high dose exposure. The enhancement of these cytoprotective mechanisms has potential value as a countermeasure to ocular alterations caused by radiation alone or in combination with other factors in spaceflight environments.

  10. Analysis of MTHFR, CBS, Glutathione, Taurine, and Hydrogen Sulfide Levels in Retinas of Hyperhomocysteinemic Mice.

    Cui, Xuezhi; Navneet, Soumya; Wang, Jing; Roon, Penny; Chen, Wei; Xian, Ming; Smith, Sylvia B

    2017-04-01

    Hyperhomocysteinemia (Hhcy) is implicated in certain retinal neurovascular diseases, although whether it is causative remains uncertain. In isolated ganglion cells (GCs), mild Hhcy induces profound death, whereas retinal phenotypes in Hhcy mice caused by mutations in remethylation (methylene tetrahydrofolatereductase [Mthfr+/-]) or transsulfuration pathways (cystathionine β-synthase [Cbs+/-]) demonstrate mild GC loss and mild vasculopathy. The current work investigated compensation in vivo of one pathway for the other, and, because the transsulfuration pathway yields cysteine necessary for formation of glutathione (GSH), taurine, and hydrogen sulfide (H2S), they were analyzed also. Retinas isolated from wild-type (WT), Mthfr+/-, and Cbs+/- mice (12 and 22 weeks) were analyzed for methylene tetrahydrofolate reductase (MTHFR), cystathionine-β-synthase (CBS), and cystathionase (CTH) RNA/protein levels. Retinas were evaluated for levels of reduced:oxidized GSH (GSH:GSSG), Slc7a11 (xCT), taurine, taurine transporter (TAUT), and H2S. Aside from decreased CBS RNA/protein levels in Cbs+/- retinas, there were minimal alterations in remethylation/transsulfuration pathways in the two mutant mice strains. Glutathione and taurine levels in Mthfr+/- and Cbs+/- retinas were similar to WT, which may be due to robust levels of xCT and TAUT in mutant retinas. Interestingly, levels of H2S were markedly increased in retinas of Mthfr+/- and Cbs+/- mice compared with WT. Ganglion cell loss and vasculopathy observed in Mthfr+/- and Cbs+/- mouse retinas may be milder than expected, not because of compensatory increases of enzymes in remethylation/transsulfuration pathways, but because downstream transsulfuration pathway products GSH, taurine, and H2S are maintained at robust levels. Elevation of H2S is particularly intriguing owing to neuroprotective properties reported for this gasotransmitter.

  11. Complement anaphylatoxin C3a is a potent inducer of embryonic chick retina regeneration

    Haynes, Tracy; Luz-Madrigal, Agustin; Reis, Edimara S.; Echeverri Ruiz, Nancy P.; Grajales-Esquivel, Erika; Tzekou, Apostolia; Tsonis, Panagiotis A.; Lambris, John D.; Del Rio-Tsonis, Katia

    2013-01-01

    Identifying the initiation signals for tissue regeneration in vertebrates is one of the major challenges in regenerative biology. Much of the research thus far has indicated that certain growth factors have key roles. Here we show that complement fragment C3a is sufficient to induce complete regeneration of the embryonic chick retina from stem/progenitor cells present in the eye, independent of fibroblast growth factor receptor signaling. Instead, C3a induces retina regeneration via STAT3 activation, which in turn activates the injury- and inflammation-responsive factors, IL-6, IL-8 and TNF-α. This activation sets forth regulation of Wnt2b, Six3 and Sox2, genes associated with retina stem and progenitor cells. Thus, our results establish a mechanism for retina regeneration based on injury and inflammation signals. Furthermore, our results indicate a unique function for complement anaphylatoxins that implicate these molecules in the induction and complete regeneration of the retina, opening new avenues of experimentation in the field. PMID:23942241

  12. Neurotransmitter properties of the newborn human retina

    Hollyfield, J.G.; Frederick, J.M.; Rayborn, M.E.

    1983-01-01

    Human retinal tissue from a newborn was examined autoradiographically for the presence of high-affinity uptake and localization of the following putative neurotransmitters: dopamine, glycine, GABA, aspartate, and glutamate. In addition, the dopamine content of this newborn retina was measured by high pressure liquid chromatography. Our study reveals that specific uptake mechanisms for 3 H-glycine, 3 H-dopamine, and 3 H-GABA are present at birth. However, the number and distribution of cells labeled with each of these 3 H-transmitters are not identical to those observed in adult human retinas. Furthermore, the amount of endogenous dopamine in the newborn retina is approximately 1/20 the adult level. Photoreceptor-specific uptake of 3 H-glutamate and 3 H-aspartate are not observed. These findings indicate that, while some neurotransmitter-specific properties are present at birth, significant maturation of neurotransmitter systems occurs postnatally

  13. Retina image–based optic disc segmentation

    Ching-Lin Wang

    2016-05-01

    Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

  14. [Degenerative lesions of the peripheral retina].

    Conart, J-B; Baron, D; Berrod, J-P

    2014-01-01

    Degenerative lesions of the peripheral retina are present from teenage years onwards and increase with age. These abnormabilities are frequent, some of them being benign while others predispose to retinal tears and detachment. In the latter case, the lesions are rhegmatogenous and may justify prophylactic treatment by laser photocoagulation. We distinguish congenital lesions of the peripheral retina and intraretinal, chorioretinal and vitreoretinal degenerations. The holes and tears observed in 2% of the population consist of round atrophic holes, "horseshoe" tears, oral dialyses and giant tears. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  15. Genetics of lattice degeneration of the retina.

    Murakami, F; Ohba, N

    1982-01-01

    First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.

  16. Research Contributing to Improvements in Controlling Florida’s Mosquitoes and Mosquito-borne Diseases

    Walter J. Tabachnick

    2016-01-01

    Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state?s mosquito control capabilities. Research with Florida?s mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida?s east coast. This strategy, called Rotational Impoundment Management (RIM...

  17. Possible influences of lutein and zeaxanthin on the developing retina.

    Zimmer, J Paul; Hammond, Billy R

    2007-03-01

    The carotenoids lutein and zeaxanthin (LZ) are found throughout the central nervous system but reach their highest concentration within the macular region of the primate retina where they are commonly referred to as the macular pigments. Although LZ are a major integral feature of the central fovea, no information currently exists regarding the effects of variability in the concentration of these pigments on the developing retina. In particular, the long-term effects of very low levels of macular pigment are not known and potentially meaningful. Macular pigment levels depend upon dietary intake since LZ cannot be synthesized de novo. Infants with low intake of LZ (eg, infants receiving unfortified infant formula or breast milk from mothers with low carotenoid diets) would be expected to have considerably lower macular pigment compared with infants with high LZ intake (eg, breast-fed infants with mothers on carotenoid-rich diets). In this paper we discuss possible implications of this difference and the available evidence suggesting that LZ could influence the developing visual system.

  18. Heritability of attractiveness to mosquitoes.

    G Mandela Fernández-Grandon

    Full Text Available Female mosquitoes display preferences for certain individuals over others, which is determined by differences in volatile chemicals produced by the human body and detected by mosquitoes. Body odour can be controlled genetically but the existence of a genetic basis for differential attraction to insects has never been formally demonstrated. This study investigated heritability of attractiveness to mosquitoes by evaluating the response of Aedes aegypti (=Stegomyia aegypti mosquitoes to odours from the hands of identical and non-identical twins in a dual-choice assay. Volatiles from individuals in an identical twin pair showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation. Overall, there was a strong narrow-sense heritability of 0.62 (SE 0.124 for relative attraction and 0.67 (0.354 for flight activity based on the average of ten measurements. The results demonstrate an underlying genetic component detectable by mosquitoes through olfaction. Understanding the genetic basis for attractiveness could create a more informed approach to repellent development.

  19. Information processing in the outer retina of fish

    Endeman, D.

    2017-01-01

    The retina translates light into neuronal activity. Thus, it renders visual information of the external environment. The retina can only send a limited amount of information to the brain within a given period. To use this amount optimally, light stimuli are strongly processed in the retina. This

  20. Chikungunya Virus Infection of Aedes Mosquitoes.

    Wong, Hui Vern; Chan, Yoke Fun; Sam, I-Ching; Sulaiman, Wan Yusof Wan; Vythilingam, Indra

    2016-01-01

    In vivo infection of mosquitoes is an important method to study and characterize arthropod-borne viruses. Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that is transmitted primarily by Aedes mosquitoes. In this chapter, we describe a protocol for infection of CHIKV in two species of Aedes mosquitoes, Aedes aegypti and Aedes albopictus, together with the isolation of CHIKV in different parts of the infected mosquito such as midgut, legs, wings, salivary gland, head, and saliva. This allows the study of viral infection, replication and dissemination within the mosquito vector.

  1. Mosquito Traps: An Innovative, Environmentally Friendly Technique to Control Mosquitoes

    Brigitte Poulin

    2017-03-01

    Full Text Available We tested the use of mosquito traps as an alternative to spraying insecticide in Camargue (France following the significant impacts observed on the non-target fauna through Bti persistence and trophic perturbations. In a village of 600 inhabitants, 16 Techno Bam traps emitting CO2 and using octenol lures were set from April to November 2016. Trap performance was estimated at 70% overall based on mosquitoes landing on human bait in areas with and without traps. The reduction of Ochlerotatus caspius and Oc. detritus, the two species targeted by Bti spraying, was, respectively, 74% and 98%. Traps were less efficient against Anopheles hyrcanus (46%, which was more attracted by lactic acid than octenol lures based on previous tests. Nearly 300,000 mosquitoes from nine species were captured, with large variations among traps, emphasizing that trap performance is also influenced by surrounding factors. Environmental impact, based on the proportion of non-target insects captured, was mostly limited to small chironomids attracted by street lights. The breeding success of a house martin colony was not significantly affected by trap use, in contrast to Bti spraying. Our experiment confirms that the deployment of mosquito traps can offer a cost-effective alternative to Bti spraying for protecting local populations from mosquito nuisance in sensitive natural areas.

  2. Abundance, composition and natural infection of Anopheles mosquitoes from two malaria-endemic regions of Colombia

    Carolina Montoya; Priscila Bascuñán; Julián Rodríguez-Zabala; Margarita M. Correa

    2017-01-01

    Introduction: In Colombia there are three Anopheles species implicated in malaria transmission as primary vectors; however, the local role of some Anopheles species must still be defined. Objective: To determine the abundance, composition and natural infection rates for Anopheles mosquitoes with Plasmodium spp. in two malaria-endemic regions of Colombia. Materials and methods: Anopheles mosquitoes were collected using the human-landing catches and while resting in livestock corrals in n...

  3. Radiation biology of mosquitoes

    Knols Bart GJ

    2009-11-01

    Full Text Available Abstract There is currently renewed interest in assessing the feasibility of the sterile insect technique (SIT to control African malaria vectors in designated areas. The SIT relies on the sterilization of males before mass release, with sterilization currently being achieved through the use of ionizing radiation. This paper reviews previous work on radiation sterilization of Anopheles mosquitoes. In general, the pupal stage was irradiated due to ease of handling compared to the adult stage. The dose-response curve between the induced sterility and log (dose was shown to be sigmoid, and there was a marked species difference in radiation sensitivity. Mating competitiveness studies have generally been performed under laboratory conditions. The competitiveness of males irradiated at high doses was relatively poor, but with increasing ratios of sterile males, egg hatch could be lowered effectively. Males irradiated as pupae had a lower competitiveness compared to males irradiated as adults, but the use of partially-sterilizing doses has not been studied extensively. Methods to reduce somatic damage during the irradiation process as well as the use of other agents or techniques to induce sterility are discussed. It is concluded that the optimal radiation dose chosen for insects that are to be released during an SIT programme should ensure a balance between induced sterility of males and their field competitiveness, with competitiveness being determined under (semi- field conditions. Self-contained 60Co research irradiators remain the most practical irradiators but these are likely to be replaced in the future by a new generation of high output X ray irradiators.

  4. Direct transdifferentiation in the vertebrate retina.

    Opas, M; Dziak, E

    1998-03-01

    Transdifferentiation is the process by which differentiated cells alter their identity to become other, distinct cell types. The conversion of neural retina into lens epithelium is one of the most spectacular examples of transdifferentiation. We show that the redirection of cell fate from neural retina to lens and subsequent transdifferentiation is independent of cell replication as it occurs in growth-arrested cell populations. Using DNA ratiometry of individual cells in these cultures we show that, indeed, individual amitotic cells do transdifferentiate. Hence, choice of fate in transdifferentiating cells does not rely on a "community effect" but instead can be categorized as a leadership effect> For lack of overt lens progenitors, and most importantly, for its mitotic independence, we conclude that lens colony formation in vitro does occur by direct transdifferentiation and not by clonal proliferation of progenitor cells.

  5. Transgenic Mosquitoes - Fact or Fiction?

    Wilke, André B B; Beier, John C; Benelli, Giovanni

    2018-06-01

    Technologies for controlling mosquito vectors based on genetic manipulation and the release of genetically modified mosquitoes (GMMs) are gaining ground. However, concrete epidemiological evidence of their effectiveness, sustainability, and impact on the environment and nontarget species is lacking; no reliable ecological evidence on the potential interactions among GMMs, target populations, and other mosquito species populations exists; and no GMM technology has yet been approved by the WHO Vector Control Advisory Group. Our opinion is that, although GMMs may be considered a promising control tool, more studies are needed to assess their true effectiveness, risks, and benefits. Overall, several lines of evidence must be provided before GMM-based control strategies can be used under the integrated vector management framework. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Thyroid Hormone Signaling in the Mouse Retina.

    Patrick Arbogast

    Full Text Available Thyroid hormone is a crucial regulator of gene expression in the developing and adult retina. Here we sought to map sites of thyroid hormone signaling at the cellular level using the transgenic FINDT3 reporter mouse model in which neurons express β-galactosidase (β-gal under the control of a hybrid Gal4-TRα receptor when triiodothyronine (T3 and cofactors of thyroid receptor signaling are present. In the adult retina, nearly all neurons of the ganglion cell layer (GCL, ganglion cells and displaced amacrine cells showed strong β-gal labeling. In the inner nuclear layer (INL, a minority of glycineric and GABAergic amacrine cells showed β-gal labeling, whereas the majority of amacrine cells were unlabeled. At the level of amacrine types, β-gal labeling was found in a large proportion of the glycinergic AII amacrines, but only in a small proportion of the cholinergic/GABAergic 'starburst' amacrines. At postnatal day 10, there also was a high density of strongly β-gal-labeled neurons in the GCL, but only few amacrine cells were labeled in the INL. There was no labeling of bipolar cells, horizontal cells and Müller glia cells at both stages. Most surprisingly, the photoreceptor somata in the outer nuclear layer also showed no β-gal label, although thyroid hormone is known to control cone opsin expression. This is the first record of thyroid hormone signaling in the inner retina of an adult mammal. We hypothesize that T3 levels in photoreceptors are below the detection threshold of the reporter system. The topographical distribution of β-gal-positive cells in the GCL follows the overall neuron distribution in that layer, with more T3-signaling cells in the ventral than the dorsal half-retina.

  7. Connecting the Retina to the Brain

    Lynda Erskine

    2014-12-01

    Full Text Available The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.

  8. The mammalian retina as a clock

    Tosini, Gianluca; Fukuhara, Chiaki

    2002-01-01

    Many physiological, cellular, and biochemical parameters in the retina of vertebrates show daily rhythms that, in many cases, also persist under constant conditions. This demonstrates that they are driven by a circadian pacemaker. The presence of an autonomous circadian clock in the retina of vertebrates was first demonstrated in Xenopus laevis and then, several years later, in mammals. In X. laevis and in chicken, the retinal circadian pacemaker has been localized in the photoreceptor layer, whereas in mammals, such information is not yet available. Recent advances in molecular techniques have led to the identification of a group of genes that are believed to constitute the molecular core of the circadian clock. These genes are expressed in the retina, although with a slightly different 24-h profile from that observed in the central circadian pacemaker. This result suggests that some difference (at the molecular level) may exist between the retinal clock and the clock located in the suprachiasmatic nuclei of hypothalamus. The present review will focus on the current knowledge of the retinal rhythmicity and the mechanisms responsible for its control.

  9. GLOBE Goes GO with Mosquitoes

    Boger, R. A.; Low, R.

    2016-12-01

    The GLOBE Mosquito Larvae protocol and a new citizen science initiative, GLOBE Observers (GO), were both launched in Summer 2016. While the GLOBE Mosquito Larvae Protocol and associated educational materials target K-16 student inquiry and research, the GO protocol version is simplified to enable citizen scientists of all ages from all walks of life to participate. GO allows citizen scientists to collect and submit environmental data through an easy-to-use smart phone app available for both Apple and Android mobile devices. GO mosquito asks for photos of larvae mosquito genus or species, location, and type of water source (e.g., container or pond) where the larvae were found. To initiate the new mosquito GLOBE/GO opportunities, workshops have been held in Barbuda, Thailand, West Indies, US Gulf Coast, New York City, and at the GLOBE Annual Meeting in Colorado. Through these venues, the protocols have been refined and a field campaign has been initiated so that GO and GLOBE citizen scientists (K-16 students and all others) can contribute data. Quality assurance measures are taken through the online training required to participate and the validation of identification by other citizen sciences and mosquito experts. Furthermore, initial research is underway to develop optical recognition software starting with the species that carry the Zika virus (Aedes aegypti and A. albopictus). With this launch, we plan to move forward by providing opportunities throughout the world to engage people in meaningful environmental and public health data collection and to promote citizen scientists to become agents of change in their communities.

  10. Spatial organization of lipids in the human retina and optic nerve by MALDI imaging mass spectrometry.

    Zemski Berry, Karin A; Gordon, William C; Murphy, Robert C; Bazan, Nicolas G

    2014-03-01

    MALDI imaging mass spectrometry (IMS) was used to characterize lipid species within sections of human eyes. Common phospholipids that are abundant in most tissues were not highly localized and observed throughout the accessory tissue, optic nerve, and retina. Triacylglycerols were highly localized in accessory tissue, whereas sulfatide and plasmalogen glycerophosphoethanolamine (PE) lipids with a monounsaturated fatty acid were found enriched in the optic nerve. Additionally, several lipids were associated solely with the inner retina, photoreceptors, or retinal pigment epithelium (RPE); a plasmalogen PE lipid containing DHA (22:6), PE(P-18:0/22:6), was present exclusively in the inner retina, and DHA-containing glycerophosphatidylcholine (PC) and PE lipids were found solely in photoreceptors. PC lipids containing very long chain (VLC)-PUFAs were detected in photoreceptors despite their low abundance in the retina. Ceramide lipids and the bis-retinoid, N-retinylidene-N-retinylethanolamine, was tentatively identified and found only in the RPE. This MALDI IMS study readily revealed the location of many lipids that have been associated with degenerative retinal diseases. Complex lipid localization within retinal tissue provides a global view of lipid organization and initial evidence for specific functions in localized regions, offering opportunities to assess their significance in retinal diseases, such as macular degeneration, where lipids have been implicated in the disease process.

  11. Zika virus replication in the mosquito Culex quinquefasciatus in Brazil.

    Guedes, Duschinka Rd; Paiva, Marcelo Hs; Donato, Mariana Ma; Barbosa, Priscilla P; Krokovsky, Larissa; Rocha, Sura W Dos S; Saraiva, Karina LA; Crespo, Mônica M; Rezende, Tatiana Mt; Wallau, Gabriel L; Barbosa, Rosângela Mr; Oliveira, Cláudia Mf; Melo-Santos, Maria Av; Pena, Lindomar; Cordeiro, Marli T; Franca, Rafael F de O; Oliveira, André Ls de; Peixoto, Christina A; Leal, Walter S; Ayres, Constância Fj

    2017-08-09

    Zika virus (ZIKV) is a flavivirus that has recently been associated with an increased incidence of neonatal microcephaly and other neurological disorders. The virus is primarily transmitted by mosquito bite, although other routes of infection have been implicated in some cases. The Aedes aegypti mosquito is considered to be the main vector to humans worldwide; however, there is evidence that other mosquito species, including Culex quinquefasciatus, transmit the virus. To test the potential of Cx. quinquefasciatus to transmit ZIKV, we experimentally compared the vector competence of laboratory-reared Ae. aegypti and Cx. quinquefasciatus. Interestingly, we were able to detect the presence of ZIKV in the midgut, salivary glands and saliva of artificially fed Cx. quinquefasciatus. In addition, we collected ZIKV-infected Cx. quinquefasciatus from urban areas with high microcephaly incidence in Recife, Brazil. Corroborating our experimental data from artificially fed mosquitoes, ZIKV was isolated from field-caught Cx. quinquefasciatus, and its genome was partially sequenced. Collectively, these findings indicate that there may be a wider range of ZIKV vectors than anticipated.

  12. Plasmodium evasion of mosquito immunity and global malaria transmission: The lock-and-key theory.

    Molina-Cruz, Alvaro; Canepa, Gaspar E; Kamath, Nitin; Pavlovic, Noelle V; Mu, Jianbing; Ramphul, Urvashi N; Ramirez, Jose Luis; Barillas-Mury, Carolina

    2015-12-08

    Plasmodium falciparum malaria originated in Africa and became global as humans migrated to other continents. During this journey, parasites encountered new mosquito species, some of them evolutionarily distant from African vectors. We have previously shown that the Pfs47 protein allows the parasite to evade the mosquito immune system of Anopheles gambiae mosquitoes. Here, we investigated the role of Pfs47-mediated immune evasion in the adaptation of P. falciparum to evolutionarily distant mosquito species. We found that P. falciparum isolates from Africa, Asia, or the Americas have low compatibility to malaria vectors from a different continent, an effect that is mediated by the mosquito immune system. We identified 42 different haplotypes of Pfs47 that have a strong geographic population structure and much lower haplotype diversity outside Africa. Replacement of the Pfs47 haplotypes in a P. falciparum isolate is sufficient to make it compatible to a different mosquito species. Those parasites that express a Pfs47 haplotype compatible with a given vector evade antiplasmodial immunity and survive. We propose that Pfs47-mediated immune evasion has been critical for the globalization of P. falciparum malaria as parasites adapted to new vector species. Our findings predict that this ongoing selective force by the mosquito immune system could influence the dispersal of Plasmodium genetic traits and point to Pfs47 as a potential target to block malaria transmission. A new model, the "lock-and-key theory" of P. falciparum globalization, is proposed, and its implications are discussed.

  13. Proteomic interactions in the mouse vitreous-retina complex.

    Jessica M Skeie

    Full Text Available Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  14. Proteomic interactions in the mouse vitreous-retina complex.

    Skeie, Jessica M; Mahajan, Vinit B

    2013-01-01

    Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina. Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software. We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor. Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  15. Mosquito Bite Prevention For Travelers

    ... bites. Here’s how: Keep mosquitoes out of your hotel room or lodging Š Choose a hotel or lodging with air conditioning or screens on ... percentages of active ingredient provide longer protection Some brand name examples* (Insect repellents may be sold under ...

  16. Looking Backward, Looking Forward: The Long, Torturous Struggle with Mosquitoes

    Gordon M. Patterson

    2016-10-01

    Full Text Available The American anti-mosquito movement grew out of the discovery of the role of mosquitoes in transferring pathogens and public concern about pest and nuisance mosquitoes in the late 1800s. In the 20th century, organized mosquito control in the United States passed through three eras: mechanical, chemical, and integrated mosquito control. Mosquito control in the 21st century faces the challenge of emerging pathogens, invasive mosquito species, and balancing concerns about the environment with effective control strategies.

  17. Relationship between exposure to vector bites and antibody responses to mosquito salivary gland extracts.

    Fontaine, Albin; Pascual, Aurélie; Orlandi-Pradines, Eve; Diouf, Ibrahima; Remoué, Franck; Pagès, Frédéric; Fusaï, Thierry; Rogier, Christophe; Almeras, Lionel

    2011-01-01

    Mosquito-borne diseases are major health problems worldwide. Serological responses to mosquito saliva proteins may be useful in estimating individual exposure to bites from mosquitoes transmitting these diseases. However, the relationships between the levels of these IgG responses and mosquito density as well as IgG response specificity at the genus and/or species level need to be clarified prior to develop new immunological markers to assess human/vector contact. To this end, a kinetic study of antibody levels against several mosquito salivary gland extracts from southeastern French individuals living in three areas with distinct ecological environments and, by implication, distinct Aedes caspius mosquito densities were compared using ELISA. A positive association was observed between the average levels of IgG responses against Ae. caspius salivary gland extracts and spatial Ae. caspius densities. Additionally, the average level of IgG responses increased significantly during the peak exposure to Ae. caspius at each site and returned to baseline four months later, suggesting short-lived IgG responses. The species-specificity of IgG antibody responses was determined by testing antibody responses to salivary gland extracts from Cx. pipiens, a mosquito that is present at these three sites at different density levels, and from two other Aedes species not present in the study area (Ae. aegypti and Ae. albopictus). The IgG responses observed against these mosquito salivary gland extracts contrasted with those observed against Ae. caspius salivary gland extracts, supporting the existence of species-specific serological responses. By considering different populations and densities of mosquitoes linked to environmental factors, this study shows, for the first time, that specific IgG antibody responses against Ae. caspius salivary gland extracts may be related to the seasonal and geographical variations in Ae. caspius density. Characterisation of such immunological

  18. Insulin-like activity in the retina

    Das, A.

    1986-01-01

    A number of studies have recently demonstrated that insulin or a homologous peptide may be synthesized outside the pancreas also. The present study was designed to investigate whether insulin-like activity exists in the retina, and if it exists, whether it is due to local synthesis of insulin or a similar peptide in the retina. To determine whether the insulin-like immunoreactivity in retinal glial cells is due to binding and uptake or local synthesis of insulin, a combined approach of immunocytochemistry and in situ DNA-RNA hybridization techniques was used on cultured rat retinal glial cells. Insulin-like immunoreactivity was demonstrated in the cytoplasma of these cells. In situ hybridization studies using labeled rat insulin cDNA indicated that these cells contain the mRNA necessary for de novo synthesis of insulin or a closely homologous peptide. Since human retinal cells have, as yet, not been conveniently grown in culture, an ocular tumor cell line, human Y79 retinoblastoma was used as a model to extend these investigations. The presence of insulin-like immunoreactivity as well as insulin-specific mRNA was demonstrated in this cell line. Light microscopic autoradiography following incubation of isolated rat retinal cells with 125 I-insulin showed the presence of insulin binding sites on the photoreceptors and amarcine cells. On the basis of these observations that rat retina glial cells, including Muller cells are sites of synthesis of insulin or a similar peptide, a model for the pathogenesis of dabetic retinopathy is proposed

  19. Lactate Transport and Receptor Actions in Retina

    Kolko, Miriam; Vosborg, Fia; Henriksen, Jens Ulrik Lütken

    2016-01-01

    known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions......In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also...

  20. Modeling laser damage to the retina

    Clark, Clifton D.

    This dissertation presents recent progress in several areas related to modeling laser damage to the retina. In Chapter 3, we consider the consequences of using the Arrhenius damage model to predict the damage thresholds of multiple pulse, or repetitive pulse, exposures. We have identified a few fundamental trends associated with the multiple pulse damage predictions made by the Arrhenius model. These trends differ from what would be expected by non-thermal mechanisms, and could prove useful in differentiating thermal and non-thermal damage. Chapter 4 presents a new rate equation damage model hypothesized to describe photochemical damage. The model adds a temperature dependent term to the simple rate equation implied by the principle of reciprocity that is characteristic of photochemical damage thresholds. A recent damage threshold study, conducted in-vitro, has revealed a very sharp transition between thermal and photochemical damage threshold trends. For the wavelength used in the experiment (413 nm), thermal damage thresholds were observed at exposure levels that were twice the expected photochemical damage threshold, based on the traditional understanding of photochemical damage. Our model accounts for this observed trend by introducing a temperature dependent quenching, or repair, rate to the photochemical damage rate. For long exposures that give a very small temperature rise, the model reduces to the principle of reciprocity. Near the transition region between thermal and photochemical damage, the model allows the damage threshold to be set by thermal mechanisms, even at exposure above the reciprocity exposure. In Chapter 5, we describe a retina damage model that includes thermal lensing in the eye by coupling beam propagation and heat transfer models together. Thermal lensing has recently been suggested as a contributing factor to the large increase in measured retinal damage thresholds in the near infrared. The transmission of the vitreous decreases

  1. Molecular Responses to the Zika Virus in Mosquitoes

    Catalina Alfonso-Parra

    2018-05-01

    Full Text Available The Zika virus (ZIKV, originally discovered in 1947, did not become a major concern until the virus swept across the Pacific and into the Americas in the last decade, bringing with it news of neurological complications and birth defects in ZIKV affected areas. This prompted researchers to dissect the molecular interactions between ZIKV and the mosquito vector in an attempt to better understand not only the changes that occur upon infection, but to also identify molecules that may potentially enhance or suppress a mosquito’s ability to become infected and/or transmit the virus. Here, we review what is currently known regarding ZIKV-mosquito molecular interactions, focusing on ZIKV infection of Aedes aegypti and Aedes albopictus, the primary species implicated in transmitting ZIKV during the recent outbreaks.

  2. Approaches to passive mosquito surveillance in the EU

    Kampen, H.; Medlock, J.M.; Vaux, A.G.C.; Koenraadt, C.J.M.; Vliet, van A.J.H.; Bartumeus, F.; Oltra, A.; Sousa, C.A.; Chouin, S.; Werner, D.

    2015-01-01

    The recent emergence in Europe of invasive mosquitoes and mosquito-borne disease associated with both invasive and native mosquito species has prompted intensified mosquito vector research in most European countries. Central to the efforts are mosquito monitoring and surveillance activities in order

  3. Glycinergic pathways in the goldfish retina

    Marc, R.E.; Lam, D.M.

    1981-01-01

    Autoradiographic localization of high affinity [3H]glycine uptake in the retina of the goldfish has been used to study some anatomical and physiological properties of potentially glycinergic neurons. There are two classes of retinal cells exhibiting high affinity glycine uptake: Aa amacrine cells and I2 interplexiform cells. Aa amacrine cells constitute about 20% of the somas in the amacrine cell layer and send their dendrites to the middle of the inner plexiform layer. There they are both pre- and postsynaptic primarily to other amacrine cells. Photic modulation of glycine uptake indicates that they are probably red-hyperpolarizing/green-depolarizing neurons. I2 interplexiform cells are a newly discovered type of interplexiform cell; in the outer plexiform layer, they receive direct synaptic input from the somas of red-dominated GABAergic H1 horizontal cells and are apparently presynaptic to dendrites of unidentified types of horizontal cells. The connections of I2 interplexiform cells have not been successfully characterized in the inner plexiform layer. These findings extend our knowledge of neurochemically specific pathways in the cyprinid retina and indicate that glycine, like GABA, is a neurotransmitter primarily involved with circuits coding ''red'' information

  4. Two classes of astrocytes in the adult human and pig retina in terms of their expression of high affinity NGF receptor (TrkA).

    Ruiz-Ederra, Javier; Hitchcock, Peter F; Vecino, Elena

    2003-02-13

    Astrocytes have been implicated in axon guidance and synaptic regeneration in the retina and these processes involve activation of the high affinity nerve growth factor receptor, known as the tyrosine kinase A (TrkA) receptor. The purpose of the present study was to characterize the expression of TrkA in astrocytes of the adult pig and human retina. To this end, sections of human and pig retinas were immunolabeled with a combination of antibodies to glial fibrillary acidic protein (GFAP) and TrkA. Our study revealed that most of the GFAP-positive cells express TrkA, whereas a rare, novel subpopulation of astrocytes was found to be devoid of TrkA. Our results support the idea that astrocytes play an important neurotrophic role in the retina.

  5. Transgenic mosquitoes expressing a phospholipase A(2 gene have a fitness advantage when fed Plasmodium falciparum-infected blood.

    Ryan C Smith

    Full Text Available Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development.We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2 into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development of human malaria parasites. In addition, when fed on malaria-infected blood, mosquitoes from both transgenic lines are more fecund than non-transgenic mosquitoes. Consistent with these observations, cage experiments with mixed populations of transgenic and non-transgenic mosquitoes show that the percentage of transgenic mosquitoes increases when maintained on Plasmodium-infected blood.Our results suggest that the expression of an anti-Plasmodium effector gene gives transgenic mosquitoes a fitness advantage when fed malaria-infected blood. These findings have important implications for future applications of transgenic mosquito technology in malaria control.

  6. Cómo controlar los mosquitos en interiores (Controlling Mosquitoes Indoors)

    Los mosquitos pueden portar virus como el del Nilo Occidental o del Zika. En este podcast, Don Francisco le muestra a sus vecinos formas en las que pueden reducir el número de mosquitos dentro de su casa.

  7. Systematics of Aedes Mosquito Project.

    1984-01-01

    Fever and Zika viruses . During a recent field trip to Cameroon and Kenya in the early part of 1983 numerous specimens were collected, mostly as reared...1942) isolated Yellow Fever virus is Aedes (Stejomyia) broeliae (Theobald) and is the common man-biting member of -th-e complex in East Africa. The...PERIOD COVERED Five Month Report Systematics of Aedes Mosquito Project August 1 - December 31, 1983 p - 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(&) S

  8. Ocular Manifestations of Mosquito-Transmitted Diseases.

    Karesh, James W; Mazzoli, Robert A; Heintz, Shannon K

    2018-03-01

    Of the 3,548 known mosquito species, about 100 transmit human diseases. Mosquitoes are distributed globally throughout tropical and temperate regions where standing water sources are available for egg laying and the maturation of larva. Female mosquitoes require blood meals for egg production. This is the main pathway for disease transmission. Mosquitoes carry several pathogenic organisms responsible for significant ocular pathology and vision loss including West Nile, Rift Valley, chikungunya, dengue viruses, various encephalitis viruses, malarial parasites, Francisella tularensis, microfilarial parasites, including Dirofilaria, Wuchereria, and Brugia spp., and human botfly larvae. Health care providers may not be familiar with many of these mosquito-transmitted diseases or their associated ocular findings delaying diagnosis, treatment, and recovery of visual function. This article aims to provide an overview of the ocular manifestations associated with mosquito-transmitted diseases.

  9. U-Pb ages and geochemistry of zircon from Proterozoic plutons of the Sawatch and Mosquito ranges, Colorado, U.S.A.: Implications for crustal growth of the central Colorado province

    Moscati, Richard J.; Premo, Wayne R.; Dewitt, Ed; Wooden, Joseph L.

    2017-01-01

    A broad study of zircons from plutonic rocks of the Sawatch and Mosquito ranges of west-central Colorado (U.S.A.) was undertaken to significantly refine the magmatic chronology and chemistry of this under-studied region of the Colorado province. This region was chosen because it lies just to the north of the suspected arc-related Gunnison-Salida volcano-plutonic terrane, which has been the subject of many recent investigations—and whose origin is still debated. Our new results provide important insights into the processes active during Proterozoic crustal evolution in this region, and they have important ramifications for broader-scope crustal evolution models for southwestern North America.Twenty-four new U-Pb ages and sequentially acquired rare-earth element (REE), U, Th, and Hf contents of zircon have been determined using the sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG). These zircon geochemistry data, in conjunction with whole-rock major- and trace-element data, provide important insights into zircon crystallization and melt fractionation, and they help to further constrain the tectonic environment of magma generation.Our detailed zircon and whole-rock data support the following three interpretations:(1) The Roosevelt Granite in the southern Sawatch Range was the oldest rock dated at 1,766 ± 7 Ma, and it intruded various metavolcanic and metasedimentary rocks. Geochemistry of both whole-rock and zircon supports the contention that this granite was produced in a magmatic arc environment and, therefore, is likely an extension of the older Dubois Greenstone Belt of the Gunnison Igneous Complex (GIC) and the Needle Mountains (1,770–1,755 Ma). Rocks of the younger Cochetopa succession of the GIC, the Salida Greenstone Belt, and the Sangre de Cristo Mountains (1,740–1,725 Ma) were not found in the Sawatch and Mosquito ranges. This observation strongly suggests that the northern edge of the Gunnison-Salida arc terrane underlies the

  10. Impact of MCT1 Haploinsufficiency on the Mouse Retina

    Peachey, Neal S.

    2018-05-02

    The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

  11. Imagen de retina de campo ultra-amplio

    Gerardo García-Aguirre

    2017-11-01

    Conclusión: Las imágenes de campo ultra-amplio han revolucionado la forma en la que estudiamos y entendemos la enfermedad de la retina. A medida que la tecnología para obtenerlas se haga más accesible, formará parte del armamentario de rutina para estudiar las enfermedades de la retina.

  12. Impact of MCT1 Haploinsufficiency on the Mouse Retina

    Peachey, Neal S.; Yu, Minzhong; Han, John Y. S.; Lengacher, Sylvain; Magistretti, Pierre J.; Pellerin, Luc; Philp, Nancy J.

    2018-01-01

    The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1+/− heterozygotes, which express half of the normal complement of MCT1. The MCT1+/− retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.

  13. Pathogenesis of Dengue Vaccine Viruses in Mosquitoes.

    1980-01-01

    1973). Sabin (1948) showed that attenuated dpngiie, passed through mosquitoes, did not revert to pathogenicity frnr man. -7- Thus even if the vaccine ...AD-A138 518 PATHOGENESIS OF DENGUE VACCINE YIRUSES IN MOSQUITOES 1/ (U) YALE UNIV NEW HAVEN CONN SCHOOL OF MEDICINE B J BEATY ET AL. 9i JAN 80 DRND7...34 ’ UNCLASSIFIED 0{) AD 0Pathogenesis of dengue vaccine viruses in mosquitoes -First Annual Report Barry I. Beaty, Ph.D. Thomas H. G

  14. North American Wetlands and Mosquito Control

    Rey, Jorge R.; Walton, William E.; Wolfe, Roger J.; Connelly, Roxanne; O’Connell, Sheila M.; Berg, Joe; Sakolsky-Hoopes, Gabrielle E.; Laderman, Aimlee D.

    2012-01-01

    Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere. PMID:23222252

  15. Tracking Dengue Virus Intra-host Genetic Diversity during Human-to-Mosquito Transmission.

    Shuzhen Sim

    Full Text Available Dengue virus (DENV infection of an individual human or mosquito host produces a dynamic population of closely-related sequences. This intra-host genetic diversity is thought to offer an advantage for arboviruses to adapt as they cycle between two very different host species, but it remains poorly characterized. To track changes in viral intra-host genetic diversity during horizontal transmission, we infected Aedes aegypti mosquitoes by allowing them to feed on DENV2-infected patients. We then performed whole-genome deep-sequencing of human- and matched mosquito-derived DENV samples on the Illumina platform and used a sensitive variant-caller to detect single nucleotide variants (SNVs within each sample. >90% of SNVs were lost upon transition from human to mosquito, as well as from mosquito abdomen to salivary glands. Levels of viral diversity were maintained, however, by the regeneration of new SNVs at each stage of transmission. We further show that SNVs maintained across transmission stages were transmitted as a unit of two at maximum, suggesting the presence of numerous variant genomes carrying only one or two SNVs each. We also present evidence for differences in selection pressures between human and mosquito hosts, particularly on the structural and NS1 genes. This analysis provides insights into how population drops during transmission shape RNA virus genetic diversity, has direct implications for virus evolution, and illustrates the value of high-coverage, whole-genome next-generation sequencing for understanding viral intra-host genetic diversity.

  16. Relative Abundance of Adult Mosquitoes in University of Abuja Main ...

    Relative Abundance of Adult Mosquitoes in University of Abuja Main ... relative abundance of adult mosquitoes in four selected sites in University of Abuja ... These results indicated that vectors of mosquito-borne diseases are breeding in the ...

  17. Molecular characterization of novel mosquito-borne Rickettsia spp. from mosquitoes collected at the Demilitarized Zone of the Republic of Korea.

    Maina, Alice N; Klein, Terry A; Kim, Heung-Chul; Chong, Sung-Tae; Yang, Yu; Mullins, Kristin; Jiang, Ju; St John, Heidi; Jarman, Richard G; Hang, Jun; Richards, Allen L

    2017-01-01

    Rickettsiae are associated with a diverse range of invertebrate hosts. Of these, mosquitoes could emerge as one of the most important vectors because of their ability to transmit significant numbers of pathogens and parasites throughout the world. Recent studies have implicated Anopheles gambiae as a potential vector of Rickettsia felis. Herein we report that a metagenome sequencing study identified rickettsial sequence reads in culicine mosquitoes from the Republic of Korea. The detected rickettsiae were characterized by a genus-specific quantitative real-time PCR assay and sequencing of rrs, gltA, 17kDa, ompB, and sca4 genes. Three novel rickettsial genotypes were detected (Rickettsia sp. A12.2646, Rickettsia sp. A12.2638 and Rickettsia sp. A12.3271), from Mansonia uniformis, Culex pipiens, and Aedes esoensis, respectively. The results underscore the need to determine the Rickettsia species diversity associated with mosquitoes, their evolution, distribution and pathogenic potential.

  18. Adaptive optics imaging of the retina

    Rajani Battu

    2014-01-01

    Full Text Available Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We attempt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO and American Academy of Ophthalmology (AAO meetings. In total, 261 relevant publications and 389 conference abstracts were identified.

  19. Probability of Transmission of Malaria from Mosquito to Human Is Regulated by Mosquito Parasite Density in Naïve and Vaccinated Hosts.

    Thomas S Churcher

    2017-01-01

    Full Text Available Over a century since Ronald Ross discovered that malaria is caused by the bite of an infectious mosquito it is still unclear how the number of parasites injected influences disease transmission. Currently it is assumed that all mosquitoes with salivary gland sporozoites are equally infectious irrespective of the number of parasites they harbour, though this has never been rigorously tested. Here we analyse >1000 experimental infections of humans and mice and demonstrate a dose-dependency for probability of infection and the length of the host pre-patent period. Mosquitoes with a higher numbers of sporozoites in their salivary glands following blood-feeding are more likely to have caused infection (and have done so quicker than mosquitoes with fewer parasites. A similar dose response for the probability of infection was seen for humans given a pre-erythrocytic vaccine candidate targeting circumsporozoite protein (CSP, and in mice with and without transfusion of anti-CSP antibodies. These interventions prevented infection more efficiently from bites made by mosquitoes with fewer parasites. The importance of parasite number has widespread implications across malariology, ranging from our basic understanding of the parasite, how vaccines are evaluated and the way in which transmission should be measured in the field. It also provides direct evidence for why the only registered malaria vaccine RTS,S was partially effective in recent clinical trials.

  20. An entomological review of invasive mosquitoes in Europe.

    Medlock, J M; Hansford, K M; Versteirt, V; Cull, B; Kampen, H; Fontenille, D; Hendrickx, G; Zeller, H; Van Bortel, W; Schaffner, F

    2015-12-01

    Among the invasive mosquitoes registered all over the world, Aedes species are particularly frequent and important. As several of them are potential vectors of disease, they present significant health concerns for 21st century Europe. Five species have established in mainland Europe, with two (Aedes albopictus and Aedes japonicus) becoming widespread and two (Ae. albopictus and Aedes aegypti) implicated in disease transmission to humans in Europe. The routes of importation and spread are often enigmatic, the ability to adapt to local environments and climates are rapid, and the biting nuisance and vector potential are both an ecomonic and public health concern. Europeans are used to cases of dengue and chikungunya in travellers returning from the tropics, but the threat to health and tourism in mainland Europe is substantive. Coupled to that are the emerging issues in the European overseas territorities and this paper is the first to consider the impacts in the remoter outposts of Europe. If entomologists and public health authorities are to address the spread of these mosquitoes and mitigate their health risks they must first be prepared to share information to better understand their biology and ecology, and share data on their distribution and control successes. This paper focusses in greater detail on the entomological and ecological aspects of these mosquitoes to assist with the risk assessment process, bringing together a large amount of information gathered through the ECDC VBORNET project.

  1. Controle los mosquitos que están en el exterior (Controlling Mosquitoes Outside)

    Los mosquitos pueden transmitir virus como el del zika. En este podcast, el Sr. Francisco le enseñará a usted y a su vecina Adriana diferentes maneras para ayudar a reducir la cantidad de mosquitos fuera de su casa. Los consejos incluyen eliminar áreas de agua estancada donde los mosquitos ponen sus huevos, usar larvicidas para matar mosquitos jóvenes, y reparar grietas y cubrir las ventilaciones de los pozos sépticos. También aprenderá cómo se usan los aviones que ayudan a rociar insecticida para los mosquitos.

  2. Topography of ganglion cell production in the cat's retina

    Walsh, C.; Polley, E.H.

    1985-01-01

    The ganglion cells of the cat's retina form several classes distinguishable in terms of soma size, axon diameter, dendritic morphology, physiological properties, and central connections. Labeling with [ 3 H]thymidine shows that the ganglion cells which survive in the adult are produced as several temporally shifted, overlapping waves: medium-sized cells are produced before large cells, whereas the smallest ganglion cells are produced throughout the period of ganglion cell generation. Large cells and medium-sized cells show the same distinctive pattern of production, forming rough spirals around the area centralis. The oldest cells tend to lie superior and nasal to the area centralis, whereas cells in the inferior nasal retina and inferior temporal retina are, in general, progressively younger. Within each retinal quadrant, cells nearer the area centralis tend to be older than cells in the periphery, but there is substantial overlap. The retinal raphe divides the superior temporal quadrant into two zones with different patterns of cell addition. Superior temporal retina near the vertical meridian adds cells only slightly later than superior nasal retina, whereas superior temporal retina near the horizontal meridian adds cells very late, contemporaneously with inferior temporal retina. The broader wave of production of smaller ganglion cells seems to follow this same spiral pattern at its beginning and end. The presence of the area centralis as a nodal point about which ganglion cell production in the retinal quadrants pivots suggests that the area centralis is already an important retinal landmark even at the earliest stages of retinal development

  3. Neurotransmitter-Regulated Regeneration in the Zebrafish Retina

    Mahesh B. Rao

    2017-04-01

    Full Text Available Summary: Current efforts to repair damaged or diseased mammalian retinas are inefficient and largely incapable of fully restoring vision. Conversely, the zebrafish retina is capable of spontaneous regeneration upon damage using Müller glia (MG-derived progenitors. Understanding how zebrafish MG initiate regeneration may help develop new treatments that prompt mammalian retinas to regenerate. We show that inhibition of γ-aminobutyric acid (GABA signaling facilitates initiation of MG proliferation. GABA levels decrease following damage, and MG are positioned to detect decreased ambient levels and undergo dedifferentiation. Using pharmacological and genetic approaches, we demonstrate that GABAA receptor inhibition stimulates regeneration in undamaged retinas while activation inhibits regeneration in damaged retinas. : Unlike mammals, zebrafish regenerate following retina damage from a resident adult stem cell (Müller glia. Dissecting the mechanisms that zebrafish use could lead to new therapeutic targets to treat retinal diseases. Patton and colleagues have discovered a mechanism by which decreased GABA levels are sensed by Müller glia to initiate a regenerative response. Keywords: zebrafish, retina, regeneration, Müller glia, GABA

  4. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration.

    Yang, Fan; Ma, Hongwei; Belcher, Joshua; Butler, Michael R; Redmond, T Michael; Boye, Sanford L; Hauswirth, William W; Ding, Xi-Qin

    2016-12-01

    Recent studies have implicated thyroid hormone (TH) signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we found that antithyroid treatment preserves cones. This work investigates the significance of targeting intracellular TH components locally in the retina. The cellular TH level is mainly regulated by deiodinase iodothyronine (DIO)-2 and -3. DIO2 converts thyroxine (T4) to triiodothyronine (T3), which binds to the TH receptor, whereas DIO3 degrades T3 and T4. We examined cone survival after overexpression of DIO3 and inhibition of DIO2 and demonstrated the benefits of these manipulations. Subretinal delivery of AAV5-IRBP/GNAT2-DIO3, which directs expression of human DIO3 specifically in cones, increased cone density by 30-40% in a Rpe65 -/- mouse model of Lebers congenital amaurosis (LCA) and in a Cpfl1 mouse with Pde6c defect model of achromatopsia, compared with their respective untreated controls. Intravitreal and topical delivery of the DIO2 inhibitor iopanoic acid also significantly improved cone survival in the LCA model mice. Moreover, the expression levels of DIO2 and Slc16a2 were significantly higher in the diseased retinas, suggesting locally elevated TH signaling. We show that targeting DIOs protects cones, and intracellular inhibition of TH components locally in the retina may represent a novel strategy for retinal degeneration management.-Yang, F., Ma, H., Belcher, J., Butler, M. R., Redmond, T. M., Boye, S. L., Hauswirth, W. W., Ding, X.-Q. Targeting iodothyronine deiodinases locally in the retina is a therapeutic strategy for retinal degeneration. © FASEB.

  5. Aquatic insect predators and mosquito control.

    Shaalan, Essam Abdel-Salam; Canyon, Deon V

    2009-12-01

    Mosquitoes are serious biting pests and obligate vectors of many vertebrate pathogens. Their immature larval and pupal life stages are a common feature in most tropical and many temperate water bodies and often form a significant proportion of the biomass. Control strategies rely primarily on the use of larvicides and environmental modification to reduce recruitment and adulticides during periods of disease transmission. Larvicides are usually chemical but can involve biological toxins, agents or organisms. The use of insect predators in mosquito control has been exploited in a limited fashion and there is much room for further investigation and implementation. Insects that are recognized as having predatorial capacity with regard to mosquito prey have been identified in the Orders Odonata, Coleoptera, Diptera (primarily aquatic predators), and Hemiptera (primarily surface predators). Although their capacity is affected by certain biological and physical factors, they could play a major role in mosquito control. Furthermore, better understanding for the mosquitoes-predators relationship(s) could probably lead to satisfactory reduction of mosquito-borne diseases by utilizing either these predators in control programs, for instance biological and/or integrated control, or their kairomones as mosquitoes' ovipoisting repellents. This review covers the predation of different insect species on mosquito larvae, predator-prey-habitat relationships, co-habitation developmental issues, survival and abundance, oviposition avoidance, predatorial capacity and integrated vector control.

  6. Microorganism-mediated behaviour of malaria mosquitoes

    Busula, Annette O.

    2017-01-01

    Host-seeking is an important component of mosquito vectorial capacity on which the success of the other behavioural determinants depends. Blood-seeking mosquitoes are mainly guided by chemical cues released by their blood hosts. This thesis describes results of a study that determined the effect

  7. Hey! A Mosquito Bit Me! (For Kids)

    ... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works ... Español Hey! A Mosquito Bit Me! KidsHealth / For Kids / Hey! A Mosquito Bit Me! Print en español ¡ ...

  8. Green Nanoparticles for Mosquito Control

    Namita Soni

    2014-01-01

    Full Text Available Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag and gold (Au nanoparticles (NPs were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum (C. zyelanicum or C. verum J. Presl. Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vector Anopheles stephensi and filariasis vector Culex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM. The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs. The larvae of An. stephensi were found highly susceptible to the synthesized AgNPs and AuNPs than the Cx. quinquefasciatus. These results suggest that the C. zeylanicum synthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito.

  9. 3D mosquito screens to create window double screen traps for mosquito control.

    Khattab, Ayman; Jylhä, Kaisa; Hakala, Tomi; Aalto, Mikko; Malima, Robert; Kisinza, William; Honkala, Markku; Nousiainen, Pertti; Meri, Seppo

    2017-08-29

    Mosquitoes are vectors for many diseases such as malaria. Insecticide-treated bed nets and indoor residual spraying of insecticides are the principal malaria vector control tools used to prevent malaria in the tropics. Other interventions aim at reducing man-vector contact. For example, house screening provides additive or synergistic effects to other implemented measures. We used commercial screen materials made of polyester, polyethylene or polypropylene to design novel mosquito screens that provide remarkable additional benefits to those commonly used in house screening. The novel design is based on a double screen setup made of a screen with 3D geometric structures parallel to a commercial mosquito screen creating a trap between the two screens. Owing to the design of the 3D screen, mosquitoes can penetrate the 3D screen from one side but cannot return through the other side, making it a unidirectional mosquito screen. Therefore, the mosquitoes are trapped inside the double screen system. The permissiveness of both sides of the 3D screens for mosquitoes to pass through was tested in a wind tunnel using the insectary strain of Anopheles stephensi. Among twenty-five tested 3D screen designs, three designs from the cone, prism, or cylinder design groups were the most efficient in acting as unidirectional mosquito screens. The three cone-, prism-, and cylinder-based screens allowed, on average, 92, 75 and 64% of Anopheles stephensi mosquitoes released into the wind tunnel to penetrate the permissive side and 0, 0 and 6% of mosquitoes to escape through the non-permissive side, respectively. A cone-based 3D screen fulfilled the study objective. It allowed capturing 92% of mosquitoes within the double screen setup inside the wind tunnel and blocked 100% from escaping. Thus, the cone-based screen effectively acted as a unidirectional mosquito screen. This 3D screen-based trap design could therefore be used in house screening as a means of avoiding infective bites and

  10. Vitreous in lattice degeneration of retina.

    Foos, R Y; Simons, K B

    1984-05-01

    A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

  11. Simulating the Effects of Laser Damage to the Retina

    2001-01-01

    This Phase II SBIR brought vision and signal processing researchers from the Air Force, academia and the public sector together to develop a visualization tool for modeling laser damage to the retina...

  12. Simple Experiments on the Physics of Vision: The Retina

    Cortel, Adolf

    2005-01-01

    Many simple experiments can be performed in the classroom to explore the physics of vision. Students can learn of the two types of receptive cells (rods and cones), their distribution on the retina and the existence of the blind spot.

  13. Plant extracts as potential mosquito larvicides.

    Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam

    2012-05-01

    Mosquitoes act as a vector for most of the life threatening diseases like malaria, yellow fever, dengue fever, chikungunya ferver, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management (IMM), emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain and adverse effects on environmental quality and non target organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are non-toxic, easily available at affordable prices, biodegradable and show broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on phytochemical sources and mosquitocidal activity, their mechanism of action on target population, variation of their larvicidal activity according to mosquito species, instar specificity, polarity of solvents used during extraction, nature of active ingredient and promising advances made in biological control of mosquitoes by plant derived secondary metabolites have been reviewed.

  14. Wolbachia-a foe for mosquitoes

    Nadipinayakanahalli Munikrishnappa Guruprasad

    2014-02-01

    Full Text Available Mosquitoes act as vectors for a wide range of viral and parasitic infectious diseases such as malaria, dengue, Chickungunya, lymphatic filariasis, Japanese encephalitis and West Nile virus in humans as well as in animals. Although a wide range of insecticides are used to control mosquitoes, it has only resulted in development of resistance to such insecticides. The evolution of insecticide resistance and lack of vaccines for many mosquito-borne diseases have made these arthropods highly harmful vectors. Recently, a novel approach to control mosquitoes by transinfection of life shortening maternally transmitted endo-symbiont Wolbachia wMelPop strain from fruitfly Drosophila into mosquito population has been developed by researchers. The wMelPop strain up-regulated the immune gene expression in mosquitoes thereby reducing the dengue and Chickungunya viral replication in Aedes aegypti, and also it significantly reduced the Plasmodium level in Anopheles gambiae. Here, we discuss the strategy of using Wolbachia in control of vector-borne diseases of mosquitoes.

  15. Monte Carlo simulation of zinc protoporphyrin fluorescence in the retina

    Chen, Xiaoyan; Lane, Stephen

    2010-02-01

    We have used Monte Carlo simulation of autofluorescence in the retina to determine that noninvasive detection of nutritional iron deficiency is possible. Nutritional iron deficiency (which leads to iron deficiency anemia) affects more than 2 billion people worldwide, and there is an urgent need for a simple, noninvasive diagnostic test. Zinc protoporphyrin (ZPP) is a fluorescent compound that accumulates in red blood cells and is used as a biomarker for nutritional iron deficiency. We developed a computational model of the eye, using parameters that were identified either by literature search, or by direct experimental measurement to test the possibility of detecting ZPP non-invasively in retina. By incorporating fluorescence into Steven Jacques' original code for multi-layered tissue, we performed Monte Carlo simulation of fluorescence in the retina and determined that if the beam is not focused on a blood vessel in a neural retina layer or if part of light is hitting the vessel, ZPP fluorescence will be 10-200 times higher than background lipofuscin fluorescence coming from the retinal pigment epithelium (RPE) layer directly below. In addition we found that if the light can be focused entirely onto a blood vessel in the neural retina layer, the fluorescence signal comes only from ZPP. The fluorescence from layers below in this second situation does not contribute to the signal. Therefore, the possibility that a device could potentially be built and detect ZPP fluorescence in retina looks very promising.

  16. Rickettsia Species in African Anopheles Mosquitoes

    Socolovschi, Cristina; Pages, Frédéric; Ndiath, Mamadou O.; Ratmanov, Pavel; Raoult, Didier

    2012-01-01

    Background There is higher rate of R. felis infection among febrile patients than in healthy people in Sub-Saharan Africa, predominantly in the rainy season. Mosquitoes possess a high vectorial capacity and, because of their abundance and aggressiveness, likely play a role in rickettsial epidemiology. Methodology/Principal Findings Quantitative and traditional PCR assays specific for Rickettsia genes detected rickettsial DNA in 13 of 848 (1.5%) Anopheles mosquitoes collected from Côte d’Ivoire, Gabon, and Senegal. R. felis was detected in one An. gambiae molecular form S mosquito collected from Kahin, Côte d’Ivoire (1/77, 1.3%). Additionally, a new Rickettsia genotype was detected in five An. gambiae molecular form S mosquitoes collected from Côte d’Ivoire (5/77, 6.5%) and one mosquito from Libreville, Gabon (1/88, 1.1%), as well as six An. melas (6/67, 9%) mosquitoes collected from Port Gentil, Gabon. A sequence analysis of the gltA, ompB, ompA and sca4 genes indicated that this new Rickettsia sp. is closely related to R. felis. No rickettsial DNA was detected from An. funestus, An. arabiensis, or An. gambiae molecular form M mosquitoes. Additionally, a BLAST analysis of the gltA sequence from the new Rickettsia sp. resulted in a 99.71% sequence similarity to a species (JQ674485) previously detected in a blood sample of a Senegalese patient with a fever from the Bandafassi village, Kedougou region. Conclusion R. felis was detected for the first time in An. gambiae molecular form S, which represents the major African malaria vector. The discovery of R. felis, as well as a new Rickettsia species, in mosquitoes raises new issues with respect to African rickettsial epidemiology that need to be investigated, such as bacterial isolation, the degree of the vectorial capacity of mosquitoes, the animal reservoirs, and human pathogenicity. PMID:23118963

  17. The costs of infection and resistance as determinants of West Nile virus susceptibility in Culex mosquitoes

    Styer Linda M

    2011-10-01

    Full Text Available Abstract Background Understanding the phenotypic consequences of interactions between arthropod-borne viruses (arboviruses and their mosquito hosts has direct implications for predicting the evolution of these relationships and the potential for changes in epidemiological patterns. Although arboviruses are generally not highly pathogenic to mosquitoes, pathology has at times been noted. Here, in order to evaluate the potential costs of West Nile virus (WNV infection and resistance in a primary WNV vector, and to assess the extent to which virus-vector relationships are species-specific, we performed fitness studies with and without WNV exposure using a highly susceptible Culex pipiens mosquito colony. Specifically, we measured and compared survival, fecundity, and feeding rates in bloodfed mosquitoes that were (i infected following WNV exposure (susceptible, (ii uninfected following WNV exposure (resistant, or (iii unexposed. Results In contrast to our previous findings with a relatively resistant Cx. tarsalis colony, WNV infection did not alter fecundity or blood-feeding behaviour of Cx. pipiens, yet results do indicate that resistance to infection is associated with a fitness cost in terms of mosquito survival. Conclusions The identification of species-specific differences provides an evolutionary explanation for variability in vector susceptibility to arboviruses and suggests that understanding the costs of infection and resistance are important factors in determining the potential competence of vector populations for arboviruses.

  18. Changes in acetylcholine release from the chick retina are not associated with myopia development

    Vessey, K.A.; Cotriall, C.L.; McBrien, N.A.

    2002-01-01

    Full text: The effectiveness of muscarinic receptor antagonists in inhibiting myopia progression in animal models and humans implicates cholinergic signalling in ocular growth regulation. Therefore to determine if changes in the release of acetylcholine from the retina are involved in myopia development, the efflux of acetylcholine from the in vitro retina of normal and myopic chick eyes was investigated. Chicks were monocularly deprived (MD) of pattern vision with translucent occluders for 2 or 7 days and refractive error of MD groups and age matched normals was monitored using retinoscopy (n=6 each group). 3 H-choline-Cl (1 Ci in 7μL) was injected into the vitreous of each eye under 2.5% halothane anaesthesia. After 1hr, the eyes were enucleated, under terminal anaesthesia (sodium pentobarbital, 120 mg/kg, im). Retinas were flat-mounted on acetate filter discs and superfused with oxygenated physiological saline solution (PSS) for 30min at 0.4mL/min. Five baseline fractions were collected (B1-B5), then three stimulated fractions were collected in the presence of PSS containing 50mM KCl (K1-K3) at 2min intervals. 3 H-acetylcholine ( 3 H-ACh) in each fraction was quantified by liquid scintillation counting. Significant amounts of myopia were induced in MD eyes after 2 (-5.1±0.8D) and 7 days (-18.8±2.4D) relative to control eyes (paired t-test p 3 H-ACh release was 146±15% above basal levels (K2/B1%) from retinas of normal animals. After 2 days MD, there was no significant difference between KCl-evoked release of 3 H-ACh from deprived eyes (147 39%) compared to control eyes (198±61%, paired t-test, p=0.27) or the eyes of normal animals (ANOVA, p>0.5). Similar results were obtained following 7 days MD. The results demonstrate that evoked acetylcholine release from the chick retina of myopic eyes is unaltered relative to control or normal eyes using an in vitro approach. Copyright (2002) Australian Neuroscience Society

  19. Fundus autofluorescence and the bisretinoids of retina.

    Sparrow, Janet R; Wu, Yalin; Nagasaki, Takayuki; Yoon, Kee Dong; Yamamoto, Kazunori; Zhou, Jilin

    2010-11-01

    Imaging of the human fundus of the eye with excitation wavelengths in the visible spectrum reveals a natural autofluorescence, that in a healthy retina originates primarily from the bisretinoids that constitute the lipofuscin of retinal pigment epithelial (RPE) cells. Since the intensity and distribution of fundus autofluorescence is altered in the presence of retinal disease, we have examined the fluorescence properties of the retinal bisretinoids with a view to aiding clinical interpretations. As is also observed for fundus autofluorescence, fluorescence emission from RPE lipofuscin was generated with a wide range of exciting wavelengths; with increasing excitation wavelength, the emission maximum shifted towards longer wavelengths and spectral width was decreased. These features are consistent with fluorescence generation from a mixture of compounds. While the bisretinoids that constitute RPE lipofuscin all fluoresced with maxima that were centered around 600 nm, fluorescence intensities varied when excited at 488 nm, the excitation wavelength utilized for fundus autofuorescence imaging. For instance the fluorescence efficiency of the bisretinoid A2-dihydropyridine-phosphatidylethanolamine (A2-DHP-PE) was greater than A2E and relative to both of the latter, all-trans-retinal dimer-phosphatidylethanolamine was weakly fluorescent. On the other hand, certain photooxidized forms of the bisretinoids present in both RPE and photoreceptor cells were more strongly fluorescent than the parent compound. We also sought to evaluate whether diffuse puncta of autofluorescence observed in some retinal disorders of monogenic origin are attributable to retinoid accumulation. However, two retinoids of the visual cycle, all-trans-retinyl ester and all-trans-retinal, did not exhibit fluorescence at 488 nm excitation.

  20. Countering a bioterrorist introduction of pathogen-infected mosquitoes through mosquito control.

    Tabachnick, Walter J; Harvey, William R; Becnel, James J; Clark, Gary G; Connelly, C Roxanne; Day, Jonathan F; Linser, Paul J; Linthicum, Kenneth J

    2011-06-01

    The release of infected mosquitoes or other arthropods by bioterrorists, i.e., arboterrorism, to cause disease and terror is a threat to the USA. A workshop to assess mosquito control response capabilities to mount rapid and effective responses to eliminate an arboterrorism attack provided recommendations to improve capabilities in the USA. It is essential that mosquito control professionals receive training in possible responses, and it is recommended that a Council for Emergency Mosquito Control be established in each state to coordinate training, state resources, and actions for use throughout the state.

  1. Entomopathogenic fungi for mosquito control: A review

    Scholte, E.J.; Knols, B.G.J.; Samson, R.A.; Takken, W.

    2004-01-01

    Fungal diseases in insects are common and widespread and can decimate their populations in spectacular epizootics. Virtually all insect orders are susceptible to fungal diseases, including Dipterans. Fungal pathogens such as Lagenidium, Coelomomyces and Culicinomyces are known to affect mosquito

  2. An analysis of diet quality, how it controls fatty acid profiles, isotope signatures and stoichiometry in the malaria mosquito Anopheles arabiensis.

    Rebecca Hood-Nowotny

    species-specific fixed parameter. This finding has significant implications for overall mosquito competitiveness and environmental management.

  3. Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya’s Lakes Victoria and Baringo

    Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W. T.; Masiga, Daniel K.

    2016-01-01

    The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. PMID:27402888

  4. Nanoparticles for mosquito control: Challenges and constraints

    Giovanni Benelli

    2017-10-01

    Full Text Available Mosquito control programs are facing important and timely challenges, including the recent outbreaks of novel arbovirus, the development of resistance in several Culicidae species, and the rapid spreading of highly invasive mosquitoes worldwide. Current control tools mainly rely on the employment of (i synthetic or microbial pesticides, (ii insecticide-treated bed nets, (iii adult repellents, (iv biological control agents against mosquito young instars (mainly fishes, amphibians and copepods (v Sterile Insect Technique (SIT, (vi “boosted SIT”, (vii symbiont-based methods and (viii transgenic mosquitoes. Currently, none of these single strategies is fully successful. Novel eco-friendly strategies to manage mosquito vectors are urgently needed. The plant-mediated fabrication of nanoparticles is advantageous over chemical and physical methods, since it is cheap, single-step, and does not require high pressure, energy, temperature, or the use of highly toxic chemicals. In the latest years, a growing number of plant-borne compounds have been proposed for efficient and rapid extracellular synthesis of metal nanoparticles effective against mosquitoes at very low doses (i.e. 1–30 ppm. In this review, we focused on the promising potential of green-fabricated nanoparticles as toxic agents against mosquito young instars, and as adult oviposition deterrents. Furthermore, we analyzed current evidences about non-target effects of these nanocomposites used for mosquito control, pointing out their moderate acute toxicity for non-target aquatic organisms, absence of genotoxicity at the doses tested against mosquitoes, and the possibility to boost the predation rates of biological control agents against mosquitoes treating the aquatic environment with ultra-low doses (e.g. 1–3 ppm of green-synthesized nanoparticles, which reduce the motility of mosquito larvae. Challenges for future research should shed light on (i the precise mechanism(s of action of

  5. Distribution of FMRFamide-like immunoreactivity in the brain, retina and nervus terminalis of the sockeye salmon parr, Oncorhynchus nerka.

    Ostholm, T; Ekström, P; Ebbesson, S O

    1990-09-01

    Neurons displaying FMRFamide(Phe - Met - Arg - Phe - NH2)-like immunoreactivity have recently been implicated in neural plasticity in salmon. We now extend these findings by describing the extent of the FMRF-like immunoreactive (FMRF-IR) system in the brain, retina and olfactory system of sockeye salmon parr using the indirect peroxidase anti-peroxidase technique. FMRF-IR perikarya were found in the periventricular hypothalamus, mesencephalic laminar nucleus, nucleus nervi terminalis and retina (presumed amacrine cells), and along the olfactory nerves. FMRF-IR fibers were distributed throughout the brain with highest densities in the ventral area of the telencephalon, in the medial forebrain bundle, and at the borders between layers III/IV and IV/V in the optic tectum. High densities of immunoreactive fibers were also observed in the area around the torus semicircularis, in the medial hypothalamus, median raphe, ventromedial tegmentum, and central gray. In the retina, immunopositive fibers were localized to the inner plexiform layer, but several fiber elements were also found in the outer plexiform layer. The olfactory system displayed FMRF-IR fibers in the epithelium and along the olfactory nerves. These findings differ from those reported in other species as follows: (i) FMRF-IR cells in the retina have not previously been reported in teleosts; (ii) the presence of FMRF-IR fibers in the outer plexiform layer of the retina is a new finding for any species; (iii) the occurrence of immunopositive cells in the mesencephalic laminar nucleus has to our knowledge not been demonstrated previously.

  6. Olfactory memory in the mosquito Culex quinquefasciatus.

    McCall, P J; Eaton, G

    2001-06-01

    The cosmotropical urban mosquito Culex quinquefasciatus Say (Diptera: Culicidae) uses chemical cues to locate suitable water pools for oviposition. Although gravid females are innately attracted to or repelled by certain compounds, this study found that an individual mosquito's preferences for these odours could be altered greatly by prior experience. Mosquitoes reared in water containing skatole, at a level normally repellent to ovipositing females, preferred to oviposit in water containing that compound rather than in water with an otherwise attractive odour compound (P-cresol). This behaviour occurred regardless of whether mosquitoes were tested individually or in groups of up to 50 per cage. The F1 progeny of conditioned mosquitoes did not exhibit the parental preference, but were as susceptible to conditioning as their parents. Moreover, rearing mosquitoes in infusions of hay or animal (guinea-pig) faeces produced a similar although less dramatic change, such that the innate propensity for hay infusion could be cancelled by rearing in guinea-pig faeces infusion. The results demonstrated a change in odour preference by Cx. quinquefasciatus following exposure to the odour during development or pupal eclosion, suggesting that some form of larval conditioning or early adult imprinting occurred. Precisely when that conditioning occurred remains to be determined.

  7. Towards metabolic mapping of the human retina.

    Schweitzer, D; Schenke, S; Hammer, M; Schweitzer, F; Jentsch, S; Birckner, E; Becker, W; Bergmann, A

    2007-05-01

    = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus. Copyright 2007 Wiley-Liss, Inc.

  8. Global Transcriptome Analysis of Aedes aegypti Mosquitoes in Response to Zika Virus Infection.

    Etebari, Kayvan; Hegde, Shivanand; Saldaña, Miguel A; Widen, Steven G; Wood, Thomas G; Asgari, Sassan; Hughes, Grant L

    2017-01-01

    Zika virus (ZIKV) of the Flaviviridae family is a recently emerged mosquito-borne virus that has been implicated in the surge of the number of microcephaly instances in South America. The recent rapid spread of the virus led to its declaration as a global health emergency by the World Health Organization. The virus is transmitted mainly by the mosquito Aedes aegypti , which is also the vector of dengue virus; however, little is known about the interactions of the virus with the mosquito vector. In this study, we investigated the transcriptome profiles of whole A. aegypti mosquitoes in response to ZIKV infection at 2, 7, and 14 days postinfection using transcriptome sequencing. Results showed changes in the abundance of a large number of transcripts at each time point following infection, with 18 transcripts commonly changed among the three time points. Gene ontology analysis revealed that most of the altered genes are involved in metabolic processes, cellular processes, and proteolysis. In addition, 486 long intergenic noncoding RNAs that were altered upon ZIKV infection were identified. Further, we found changes of a number of potential mRNA target genes correlating with those of altered host microRNAs. The outcomes provide a basic understanding of A. aegypti responses to ZIKV and help to determine host factors involved in replication or mosquito host antiviral response against the virus. IMPORTANCE Vector-borne viruses pose great risks to human health. Zika virus has recently emerged as a global threat, rapidly expanding its distribution. Understanding the interactions of the virus with mosquito vectors at the molecular level is vital for devising new approaches in inhibiting virus transmission. In this study, we embarked on analyzing the transcriptional response of Aedes aegypti mosquitoes to Zika virus infection. Results showed large changes in both coding and long noncoding RNAs. Analysis of these genes showed similarities with other flaviviruses, including

  9. Retina neural circuitry seen with particle detector technology

    CERN Bulletin

    2010-01-01

    Using particle physics techniques, high energy physics researchers have recently provided new insight into neural circuits inside the retina. After uncovering a new type of retinal cell and mapping how the retina deals with colours, the team from Santa Cruz (US), Krakow and Glasgow is now turning its attention to more complex issues such as how the retina gets wired up and how the brain deals with the signals it receives from the retina. All this using technology derived from high-density, multistrip silicon detectors…   Seen from the point of view of a particle physicist, eyes are image detectors that can gather many different types of data: light and dark, different colours, motion, etc. In particular, the retina, a thin tissue that lines the back of the eye, is a biological pixel detector that detects light and converts it to electrical signals that travel through the optic nerve to the brain. Neurobiologists know that many different cell types are involved in these processes, but they...

  10. Research Contributing to Improvements in Controlling Florida's Mosquitoes and Mosquito-borne Diseases.

    Tabachnick, Walter J

    2016-09-28

    Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state's mosquito control capabilities. Research with Florida's mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida's east coast. This strategy, called Rotational Impoundment Management (RIM), has improved the ability to target the delivery of pesticides and has helped to reduce non-target effects and environmental damage. Research has led to the development of an arbovirus surveillance system which includes sentinel chicken surveillance, real time use of environmental contributing factors like meteorology and hydrology to target mosquito control, as well as public health efforts to mitigate disease outbreaks to areas with risk of disease. These research driven improvements have provided substantial benefits to all of Florida. More research is needed to meet the future challenges to reduce emerging pathogens like Zika virus and the consequences of environmental changes like global climate change that are likely to influence the effects of mosquito-borne pathogens on human health and well-being.

  11. Research Contributing to Improvements in Controlling Florida’s Mosquitoes and Mosquito-Borne Diseases

    Tabachnick, Walter J.

    2016-01-01

    Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state’s mosquito control capabilities. Research with Florida’s mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida’s east coast. This strategy, called Rotational Impoundment Management (RIM), has improved the ability to target the delivery of pesticides and has helped to reduce non-target effects and environmental damage. Research has led to the development of an arbovirus surveillance system which includes sentinel chicken surveillance, real time use of environmental contributing factors like meteorology and hydrology to target mosquito control, as well as public health efforts to mitigate disease outbreaks to areas with risk of disease. These research driven improvements have provided substantial benefits to all of Florida. More research is needed to meet the future challenges to reduce emerging pathogens like Zika virus and the consequences of environmental changes like global climate change that are likely to influence the effects of mosquito-borne pathogens on human health and well-being. PMID:27690112

  12. Research Contributing to Improvements in Controlling Florida’s Mosquitoes and Mosquito-borne Diseases

    Walter J. Tabachnick

    2016-09-01

    Full Text Available Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state’s mosquito control capabilities. Research with Florida’s mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida’s east coast. This strategy, called Rotational Impoundment Management (RIM, has improved the ability to target the delivery of pesticides and has helped to reduce non-target effects and environmental damage. Research has led to the development of an arbovirus surveillance system which includes sentinel chicken surveillance, real time use of environmental contributing factors like meteorology and hydrology to target mosquito control, as well as public health efforts to mitigate disease outbreaks to areas with risk of disease. These research driven improvements have provided substantial benefits to all of Florida. More research is needed to meet the future challenges to reduce emerging pathogens like Zika virus and the consequences of environmental changes like global climate change that are likely to influence the effects of mosquito-borne pathogens on human health and well-being.

  13. Mosquito-specific and mosquito-borne viruses: evolution, infection, and host defense

    Halbach, R.; Junglen, S.; Rij, R.P. van

    2017-01-01

    Recent virus discovery programs have identified an extensive reservoir of viruses in arthropods. It is thought that arthropod viruses, including mosquito-specific viruses, are ancestral to vertebrate-pathogenic arboviruses. Mosquito-specific viruses are restricted in vertebrate cells at multiple

  14. Avian Plasmodium in Eastern Austrian mosquitoes.

    Schoener, Ellen; Uebleis, Sarah Susanne; Butter, Julia; Nawratil, Michaela; Cuk, Claudia; Flechl, Eva; Kothmayer, Michael; Obwaller, Adelheid G; Zechmeister, Thomas; Rubel, Franz; Lebl, Karin; Zittra, Carina; Fuehrer, Hans-Peter

    2017-09-29

    Insect vectors, namely mosquitoes (Diptera: Culicidae), are compulsory for malaria parasites (Plasmodium spp.) to complete their life cycle. Despite this, little is known about vector competence of different mosquito species for the transmission of avian malaria parasites. In this study, nested PCR was used to determine Plasmodium spp. occurrence in pools of whole individuals, as well as the diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across Eastern Austria in 2013-2015. A total of 45,749 mosquitoes in 2628 pools were collected, of which 169 pools (6.43%) comprising 9 mosquito species were positive for avian Plasmodium, with the majority of positives in mosquitoes of Culex pipiens s.l./Culex torrentium. Six different avian Plasmodium lineages were found, the most common were Plasmodium vaughani SYAT05, Plasmodium sp. Linn1 and Plasmodium relictum SGS1. In 2014, mosquitoes of the Culex pipiens complex were genetically identified and Culex pipiens f. pipiens presented with the highest number of avian Plasmodium positives (n = 37; 16.74%). Despite this, the minimum infection rate (MIR) was highest in Culex torrentium (5.36%) and Culex pipiens f. pipiens/f. molestus hybrids (5.26%). During 2014 and 2015, seasonal and annual changes in Plasmodium lineage distribution were also observed. In both years P. vaughani SYAT05 dominated at the beginning of the sampling period to be replaced later in the year by P. relictum SGS1 (2014) and Plasmodium sp. Linn1 (2015). This is the first large-scale study of avian Plasmodium parasites in Austrian mosquitoes. These results are of special interest, because molecular identification of the taxa of the Cx. pipiens complex and Cx. torrentium enabled the determination of Plasmodium prevalence in the different mosquito taxa and hybrids of this complex. Since pools of whole insects were used, it is not possible to assert any vector competence in any of the examined mosquitoes, but the results

  15. Pond dyes are Culex mosquito oviposition attractants

    Natali Ortiz Perea

    2017-05-01

    Full Text Available Background British mosquito population distribution, abundance, species composition and potential for mosquito disease transmission are intimately linked to the physical environment. The presence of ponds and water storage can significantly increase the density of particular mosquito species in the garden. Culex pipiens is the mosquito most commonly found in UK gardens and a potential vector of West Nile Virus WNV, although the current risk of transmission is low. However any factors that significantly change the distribution and population of C. pipiens are likely to impact subsequent risk of disease transmission. Pond dyes are used to control algal growth and improve aesthetics of still water reflecting surrounding planting. However, it is well documented that females of some species of mosquito prefer to lay eggs in dark water and/or containers of different colours and we predict that dyed ponds will be attractive to Culex mosquitoes. Methods Black pond dye was used in oviposition choice tests using wild-caught gravid C. pipiens. Larvae from wild-caught C. pipiens were also reared in the pond dye to determine whether it had any impact on survival. An emergence trap caught any adults that emerged from the water. Water butts (80 L were positioned around university glasshouses and woodland and treated with black pond dye or left undyed. Weekly sampling over a six month period through summer and autumn was performed to quantified numbers of larvae and pupae in each treatment and habitat. Results Gravid female Culex mosquitoes preferred to lay eggs in dyed water. This was highly significant in tests conducted under laboratory conditions and in a semi-field choice test. Despite this, survivorship in black dyed water was significantly reduced compared to undyed water. Seasonal analysis of wild larval and pupal numbers in two habitats with and without dye showed no impact of dye but a significant impact of season and habitat. Mosquitoes were more

  16. Controle los mosquitos que están en el exterior (Controlling Mosquitoes Outside)

    2016-07-11

    Los mosquitos pueden transmitir virus como el del zika. En este podcast, el Sr. Francisco le enseñará a usted y a su vecina Adriana diferentes maneras para ayudar a reducir la cantidad de mosquitos fuera de su casa. Los consejos incluyen eliminar áreas de agua estancada donde los mosquitos ponen sus huevos, usar larvicidas para matar mosquitos jóvenes, y reparar grietas y cubrir las ventilaciones de los pozos sépticos. También aprenderá cómo se usan los aviones que ayudan a rociar insecticida para los mosquitos.  Created: 7/11/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 7/11/2016.

  17. Inhibition of thyroid hormone receptor locally in the retina is a therapeutic strategy for retinal degeneration.

    Ma, Hongwei; Yang, Fan; Butler, Michael R; Belcher, Joshua; Redmond, T Michael; Placzek, Andrew T; Scanlan, Thomas S; Ding, Xi-Qin

    2017-08-01

    Thyroid hormone (TH) signaling regulates cell proliferation, differentiation, and metabolism. Recent studies have implicated TH signaling in cone photoreceptor viability. Using mouse models of retinal degeneration, we demonstrated that antithyroid drug treatment and targeting iodothyronine deiodinases (DIOs) to suppress cellular tri-iodothyronine (T3) production or increase T3 degradation preserves cones. In this work, we investigated the effectiveness of inhibition of the TH receptor (TR). Two genes, THRA and THRB , encode TRs; THRB 2 has been associated with cone viability. Using TR antagonists and Thrb2 deletion, we examined the effects of TR inhibition. Systemic and ocular treatment with the TR antagonists NH-3 and 1-850 increased cone density by 30-40% in the Rpe65 -/- mouse model of Leber congenital amaurosis and reduced the number of TUNEL + cells. Cone survival was significantly improved in Rpe65 -/- and Cpfl1 (a model of achromatopsia with Pde6c defect) mice with Thrb2 deletion. Ventral cone density in Cpfl1/Thrb2 -/- and Rpe65 -/- / Thrb2 -/- mice was increased by 1- to 4-fold, compared with age-matched controls. Moreover, the expression levels of TR were significantly higher in the cone-degeneration retinas, suggesting locally elevated TR signaling. This work shows that the effects of antithyroid treatment or targeting DIOs were likely mediated by TRs and that suppressing TR protects cones. Our findings support the view that inhibition of TR locally in the retina is a therapeutic strategy for retinal degeneration management.-Ma, H., Yang, F., Butler, M. R., Belcher, J., Redmond, T. M., Placzek, A. T., Scanlan, T. S., Ding, X.-Q. Inhibition of thyroid hormone receptor locally in the retina is a therapeutic strategy for retinal degeneration. © FASEB.

  18. [Lattice degeneration of the peripheral retina: ultrastructural study].

    Bec, P; Malecaze, F; Arne, J L; Mathis, A

    1985-01-01

    The ultrastructural study of a case of snail track degeneration shows the presence of lipid inclusions in both the glial and the macrophage cells in every layer of the retina, and the existence of intraretinal fibers different from collagen fibers appearing to be glial filaments similar to those found in astrocytic gliomes and to the Rosenthal fibers observed in senile nervous cells. Other features were thinning of the retina and absence of blood vessels in the retina. There are no abnormalities of the vitreo-retinal juncture. All the lesions are in agreement with those observed by Daicker [Ophthalmologica, Basel 165: 360-365, 1972; Klin. Mbl. Augenheilk. 172: 581-583, 1978] with some differences, however. They are different from those found in lattice degeneration. They show that snail track degeneration is a specific form of peripheral retinal degeneration which is quite different from lattice degeneration and must not be considered similar.

  19. The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis.

    Adam Kenney

    Full Text Available Francisella tularensis is disseminated in nature by biting arthropods such as mosquitoes. The relationship between mosquitoes and F. tularensis in nature is highly ambiguous, due in part to the fact that mosquitoes have caused significant tularemia outbreaks despite being classified as a mechanical vector of F. tularensis. One possible explanation for mosquitoes being a prominent, yet mechanical vector is that these insects feed on flower nectar between blood meals, allowing for transmission of F. tularensis between mosquitoes. Here, we aimed to assess whether F. tularensis could survive in flower nectar. Moreover, we examined if mosquitoes could interact with or ingest and transmit F. tularensis from one source of nectar to another. F. tularensis exhibited robust survivability in flower nectar with concentrations of viable bacteria remaining consistent with the rich growth medium. Furthermore, F. tularensis was able to survive (albeit to a lesser extent in 30% sucrose (a nectar surrogate over a period of time consistent with that of a typical flower bloom. Although we observed diminished bacterial survival in the nectar surrogate, mosquitoes that fed on this material became colonized with F. tularensis. Finally, colonized mosquitoes were capable of transferring F. tularensis to a sterile nectar surrogate. These data suggest that flower nectar may be capable of serving as a temporary source of F. tularensis that could contribute to the amplification of outbreaks. Mosquitoes that feed on an infected mammalian host and subsequently feed on flower nectar could deposit some F. tularensis bacteria into the nectar in the process. Mosquitoes subsequently feeding on this nectar source could potentially become colonized by F. tularensis. Thus, the possibility exists that flower nectar may allow for vector-vector transmission of F. tularensis.

  20. The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis.

    Kenney, Adam; Cusick, Austin; Payne, Jessica; Gaughenbaugh, Anna; Renshaw, Andrea; Wright, Jenna; Seeber, Roger; Barnes, Rebecca; Florjanczyk, Aleksandr; Horzempa, Joseph

    2017-01-01

    Francisella tularensis is disseminated in nature by biting arthropods such as mosquitoes. The relationship between mosquitoes and F. tularensis in nature is highly ambiguous, due in part to the fact that mosquitoes have caused significant tularemia outbreaks despite being classified as a mechanical vector of F. tularensis. One possible explanation for mosquitoes being a prominent, yet mechanical vector is that these insects feed on flower nectar between blood meals, allowing for transmission of F. tularensis between mosquitoes. Here, we aimed to assess whether F. tularensis could survive in flower nectar. Moreover, we examined if mosquitoes could interact with or ingest and transmit F. tularensis from one source of nectar to another. F. tularensis exhibited robust survivability in flower nectar with concentrations of viable bacteria remaining consistent with the rich growth medium. Furthermore, F. tularensis was able to survive (albeit to a lesser extent) in 30% sucrose (a nectar surrogate) over a period of time consistent with that of a typical flower bloom. Although we observed diminished bacterial survival in the nectar surrogate, mosquitoes that fed on this material became colonized with F. tularensis. Finally, colonized mosquitoes were capable of transferring F. tularensis to a sterile nectar surrogate. These data suggest that flower nectar may be capable of serving as a temporary source of F. tularensis that could contribute to the amplification of outbreaks. Mosquitoes that feed on an infected mammalian host and subsequently feed on flower nectar could deposit some F. tularensis bacteria into the nectar in the process. Mosquitoes subsequently feeding on this nectar source could potentially become colonized by F. tularensis. Thus, the possibility exists that flower nectar may allow for vector-vector transmission of F. tularensis.

  1. The influence of mosquito resting behaviour and associated microclimate for malaria risk

    Thomas Matthew B

    2011-07-01

    Full Text Available Abstract Background The majority of the mosquito and parasite life-history traits that combine to determine malaria transmission intensity are temperature sensitive. In most cases, the process-based models used to estimate malaria risk and inform control and prevention strategies utilize measures of mean outdoor temperature. Evidence suggests, however, that certain malaria vectors can spend large parts of their adult life resting indoors. Presentation of hypothesis If significant proportions of mosquitoes are resting indoors and indoor conditions differ markedly from ambient conditions, simple use of outdoor temperatures will not provide reliable estimates of malaria transmission intensity. To date, few studies have quantified the differential effects of indoor vs outdoor temperatures explicitly, reflecting a lack of proper understanding of mosquito resting behaviour and associated microclimate. Testing the hypothesis Published records from 8 village sites in East Africa revealed temperatures to be warmer indoors than outdoors and to generally show less daily variation. Exploring the effects of these temperatures on malaria parasite development rate suggested indoor-resting mosquitoes could transmit malaria between 0.3 and 22.5 days earlier than outdoor-resting mosquitoes. These differences translate to increases in transmission risk ranging from 5 to approaching 3,000%, relative to predictions based on outdoor temperatures. The pattern appears robust for low- and highland areas, with differences increasing with altitude. Implications of the hypothesis Differences in indoor vs outdoor environments lead to large differences in the limits and the intensity of malaria transmission. This finding highlights a need to better understand mosquito resting behaviour and the associated microclimate, and to broaden assessments of transmission ecology and risk to consider the potentially important role of endophily.

  2. Characteristics of Aedes aegypti adult mosquitoes in rural and urban areas of western and coastal Kenya

    Ndenga, Bryson Alberto; Mutuku, Francis Maluki; Ngugi, Harun Njenga; Mbakaya, Joel Omari; Aswani, Peter; Musunzaji, Peter Siema; Vulule, John; Mukoko, Dunstan; Kitron, Uriel; LaBeaud, Angelle Desiree

    2017-01-01

    Aedes aegypti is the main vector for yellow fever, dengue, chikungunya and Zika viruses. Recent outbreaks of dengue and chikungunya have been reported in Kenya. Presence and abundance of this vector is associated with the risk for the occurrence and transmission of these diseases. This study aimed to characterize the presence and abundance of Ae. aegypti adult mosquitoes from rural and urban sites in western and coastal regions of Kenya. Presence and abundance of Ae. aegypti adult mosquitoes were determined indoors and outdoors in two western (urban Kisumu and rural Chulaimbo) and two coastal (urban Ukunda and rural Msambweni) sites in Kenya. Sampling was performed using quarterly human landing catches, monthly Prokopack automated aspirators and monthly Biogents-sentinel traps. A total of 2,229 adult Ae. aegypti mosquitoes were collected: 785 (35.2%) by human landing catches, 459 (20.6%) by Prokopack aspiration and 985 (44.2%) by Biogents-sentinel traps. About three times as many Ae. aegypti mosquitoes were collected in urban than rural sites (1,650 versus 579). Comparable numbers were collected in western (1,196) and coastal (1,033) sites. Over 80% were collected outdoors through human landing catches and Prokopack aspiration. The probability of collecting Ae. aegypti mosquitoes by human landing catches was significantly higher in the afternoon than morning hours (Paegypti mosquitoes were collected using Prokopack aspiration outdoors than indoors (Paegypti bites was highest in urban areas, outdoors and in the afternoon hours. These characteristics have major implications for the possible transmission of arboviral diseases and for the planning of surveillance and control programs. PMID:29261766

  3. Natural variation in virulence of the entomopathogenic fungus Beauveria bassiana against malaria mosquitoes.

    Valero-Jiménez, Claudio A; Debets, Alfons J M; van Kan, Jan A L; Schoustra, Sijmen E; Takken, Willem; Zwaan, Bas J; Koenraadt, Constantianus J M

    2014-12-06

    Insecticide resistance is greatly hampering current efforts to control malaria and therefore alternative methods are needed. Entomopathogenic fungi have been proposed as an alternative with a special focus on the cosmopolitan species Beauveria bassiana. However, few studies have analysed the effects of natural variation within fungal isolates on mosquito survival, and the implications and possible exploitation for malaria control. Laboratory bioassays were performed on adult female mosquitoes (Anopheles coluzzii) with spores from 29 isolates of B. bassiana, originating from different parts of the world. In addition, phenotypic characteristics of the fungal isolates such as sporulation, spore size and growth rate were studied to explore their relationship with virulence. All tested isolates of B. bassiana killed An. coluzzii mosquitoes, and the rate at which this happened differed significantly among the isolates. The risk of mosquitoes dying was around ten times higher when they were exposed to the most virulent as compared to the least virulent isolate. There was significant variation among isolates in spore size, growth rate and sporulation, but none of these morphological characteristics were correlated, and thus predictive, for the ability of the fungal isolate to kill malaria mosquitoes. This study shows that there is a wide natural variation in virulence of isolates of B. bassiana, and that selecting an appropriate fungal isolate is highly relevant in killing and thus controlling malaria mosquitoes, particularly if used as part of an integrated vector management strategy. Also, the wide variation observed in virulence offers the opportunity to better understand the molecular and genetic mechanisms that drive this variation and thus to address the potential development of resistance against entomopathogenic fungi.

  4. Image Signal Transfer Method in Artificial Retina using Laser

    Yoon, I.Y.; Lee, B.H.; Kim, S.J. [Seoul National University, Seoul (Korea)

    2002-05-01

    Recently, the research on artificial retina for the blind is active. In this paper a new optical link method for the retinal prosthesis is proposed. Laser diode system was chosen to transfer image into the eye in this project and the new optical system was designed and evaluated. The use of laser diode array in artificial retina system makes system simple for lack of signal processing part inside of the eyeball. Designed optical system is enough to focus laser diode array on photodiode array in 20X20 application. (author). 11 refs., 7 figs., 2 tabs.

  5. Retina-like sensor image coordinates transformation and display

    Cao, Fengmei; Cao, Nan; Bai, Tingzhu; Song, Shengyu

    2015-03-01

    For a new kind of retina-like senor camera, the image acquisition, coordinates transformation and interpolation need to be realized. Both of the coordinates transformation and interpolation are computed in polar coordinate due to the sensor's particular pixels distribution. The image interpolation is based on sub-pixel interpolation and its relative weights are got in polar coordinates. The hardware platform is composed of retina-like senor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes the real-time image acquisition, coordinate transformation and interpolation.

  6. EVALUATION OF INHOMOGENEITIES IN HISTOLOGICAL STRUCTURES (CARTILAGE, RETINA

    Lutz Muche

    2011-05-01

    Full Text Available This paper investigates histological tissues by means of image analysis and spatial statistics. For the quantification of cell frequencies and accumulations two statistical characteristics, intensity function and cluster density, are suggested. The samples are histological sections of human articular cartilage and human retina considered in view of changes during the ageing process. The articular cartilage is characterized by continuous changes of both functions, the cell intensity as well as the clusterization. In contrast, the retina is a trilaminar structure formed in the early embryonic stage without changes by ageing.

  7. Does mosquito control have an effect on mosquito-borne disease? The case of Ross River virus disease and mosquito management in Queensland, Australia.

    Tomerini, Deanna M; Dale, Pat E; Sipe, Neil

    2011-03-01

    We examined the relationship between types of mosquito control programs and the mosquito-borne Ross River virus (RRV) disease in Queensland, Australia. Mosquito control information was collected through a survey of the responsible agencies (local governments), and RRV disease notification data were provided by the Queensland state health authority. The study developed a typology of mosquito control programs, based on the approaches used. Based on the analysis of data on RRV disease rates between mosquito control types within 4 climatic regions, each region had different combinations of mosquito control strategies in their programs; there were also general similarities in the relationship between program types and RRV rates between the regions. The long-term RRV disease rates were lower in areas where the mosquito control program included pre-emptive (rather than reactive) surveillance based on an extensive (rather than incomplete) knowledge of mosquito habitats, and where treatment of both saltwater and freshwater habitats (compared to only saltwater habitats, in coastal areas) occurred. The data indicate that mosquito control is an effective public health intervention to reduce mosquito-borne disease; hence, climate change adaptation strategies should ensure that adequate resources are available for effective vector control so as to manage the risk of mosquito-borne diseases.

  8. Whole-Retina Reduced Electrophysiological Activity in Mice Bearing Retina-Specific Deletion of Vesicular Acetylcholine Transporter.

    Jake Bedore

    Full Text Available Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina.A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina- targeted (embryonic day 12.5 deletion of VAChT (VAChTSix3-Cre-flox/flox and littermate controls at 5 and 12 months of age. VAChTSix3-Cre-flox/flox mice did not show any gross changes in nuclear layer cellularity or synaptic layer thickness. However, VAChTSix3-Cre-flox/flox mice showed reduced electrophysiological response of the retina to light stimulus under scotopic conditions at 5 and 12 months of age, including reduced a-wave, b-wave, and oscillatory potential (OP amplitudes and decreased OP peak power and total energy. Reduced a-wave amplitude was proportional to the reduction in b-wave amplitude and not associated with altered a-wave 10%-90% rise time or inner and outer segment thicknesses.This study used a novel genetic model in the first examination of function and structure of the mature mouse retina with disruption of cholinergic signalling. Reduced amplitude across the electroretinogram wave form does not suggest dysfunction in specific retinal cell types and could reflect underlying changes in the retinal and/or extraretinal microenvironment. Our findings suggest that release of acetylcholine by VAChT is essential for the normal electrophysiological response of the mature mouse retina.

  9. Predicting the mosquito species and vertebrate species involved in the theoretical transmission of Rift Valley fever virus in the United States.

    Golnar, Andrew J; Turell, Michael J; LaBeaud, A Desiree; Kading, Rebekah C; Hamer, Gabriel L

    2014-09-01

    Rift Valley fever virus (RVFV) is a mosquito-borne virus in the family Bunyaviridiae that has spread throughout continental Africa to Madagascar and the Arabian Peninsula. The establishment of RVFV in North America would have serious consequences for human and animal health in addition to a significant economic impact on the livestock industry. Published and unpublished data on RVFV vector competence, vertebrate host competence, and mosquito feeding patterns from the United States were combined to quantitatively implicate mosquito vectors and vertebrate hosts that may be important to RVFV transmission in the United States. A viremia-vector competence relationship based on published mosquito transmission studies was used to calculate a vertebrate host competence index which was then combined with mosquito blood feeding patterns to approximate the vector and vertebrate amplification fraction, defined as the relative contribution of the mosquito or vertebrate host to pathogen transmission. Results implicate several Aedes spp. mosquitoes and vertebrates in the order Artiodactyla as important hosts for RVFV transmission in the U.S. Moreover, this study identifies critical gaps in knowledge which would be necessary to complete a comprehensive analysis identifying the different contributions of mosquitoes and vertebrates to potential RVFV transmission in the U.S. Future research should focus on (1) the dose-dependent relationship between viremic exposure and the subsequent infectiousness of key mosquito species, (2) evaluation of vertebrate host competence for RVFV among North American mammal species, with particular emphasis on the order Artiodactyla, and (3) identification of areas with a high risk for RVFV introduction so data on local vector and host populations can help generate geographically appropriate amplification fraction estimates.

  10. Predicting the mosquito species and vertebrate species involved in the theoretical transmission of Rift Valley fever virus in the United States.

    Andrew J Golnar

    2014-09-01

    Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne virus in the family Bunyaviridiae that has spread throughout continental Africa to Madagascar and the Arabian Peninsula. The establishment of RVFV in North America would have serious consequences for human and animal health in addition to a significant economic impact on the livestock industry. Published and unpublished data on RVFV vector competence, vertebrate host competence, and mosquito feeding patterns from the United States were combined to quantitatively implicate mosquito vectors and vertebrate hosts that may be important to RVFV transmission in the United States. A viremia-vector competence relationship based on published mosquito transmission studies was used to calculate a vertebrate host competence index which was then combined with mosquito blood feeding patterns to approximate the vector and vertebrate amplification fraction, defined as the relative contribution of the mosquito or vertebrate host to pathogen transmission. Results implicate several Aedes spp. mosquitoes and vertebrates in the order Artiodactyla as important hosts for RVFV transmission in the U.S. Moreover, this study identifies critical gaps in knowledge which would be necessary to complete a comprehensive analysis identifying the different contributions of mosquitoes and vertebrates to potential RVFV transmission in the U.S. Future research should focus on (1 the dose-dependent relationship between viremic exposure and the subsequent infectiousness of key mosquito species, (2 evaluation of vertebrate host competence for RVFV among North American mammal species, with particular emphasis on the order Artiodactyla, and (3 identification of areas with a high risk for RVFV introduction so data on local vector and host populations can help generate geographically appropriate amplification fraction estimates.

  11. Analysis of a malaria model with mosquito-dependent transmission ...

    model for the spread of malaria in human and mosquito population. ... tures, high humidity and water bodies allow mosquito and parasites to reproduce. The ... understand the main parameters in the transmission of the disease and to develop ...

  12. Avaliação ocular multimodal em doenças heredodistróficas e degenerativas da retina Multimodal fundus imaging in heredodystrophic and degenerative diseases of the retina

    Daniela Cavalcanti Ferrara

    2009-10-01

    has permitted the acquisition of tomographic images driven by different imaging modalities simultaneously (fundus autofluorescence, near-infrared reflectance, and fluorescein or indocyanine-green angiographies. Multimodal fundus imaging permits a reliable and detailed correlation between the morphological findings of the retina or retinal pigment epithelium and angiographic studies or fundus autofluorescence, leading to valuable insights about retina physiology. In this article, we briefly discuss possible practical implications of this new diagnostic modality for the retina specialist.

  13. MosqTent: An individual portable protective double-chamber mosquito trap for anthropophilic mosquitoes.

    José Bento Pereira Lima

    2017-03-01

    Full Text Available Here, we describe the development of the MosqTent, an innovative double-chamber mosquito trap in which a human being attracts mosquitoes while is protected from being bitten within the inner chamber of the trap, while mosquitoes are lured to enter an outer chamber where they are trapped. The MosqTent previously collected an average of 3,000 anophelines/man-hour compared to 240 anophelines/man-hour for the human landing catch (HLC, thereby providing high numbers of human host-seeking mosquitoes while protecting the collector from mosquito bites. The MosqTent performed well by collecting a high number of specimens of Anopheles marajoara, a local vector and anthropophilic mosquito species present in high density, but not so well in collecting An. darlingi, an anthropophilic mosquito species considered the main vector in Brazil but is present in low-density conditions in the area. The HLC showed a higher efficiency in collecting An. darlingi in these low-density conditions. The MosqTent is light (<1 kg, portable (comes as a bag with two handles, flexible (can be used with other attractants, adaptable (can be deployed in a variety of environmental settings and weather conditions, and it can be used in the intra-, peri-, and in the extradomicile. Also, the MosqTent collected similar portions of parous females and anthropophilic mosquito species and collects specimens suitable for downstream analysis. Further developments may include testing for other fabric colors, different mesh sizes and dimensions for other hematophagous insects and conditions, additional chemical mosquito attractants, and even the replacement of the human attractant in favor of other attractants. MosqTent modifications that would allow the trap to be applied as a vector control tool with killing action could also be explored.

  14. Progranulin regulates neurogenesis in the developing vertebrate retina.

    Walsh, Caroline E; Hitchcock, Peter F

    2017-09-01

    We evaluated the expression and function of the microglia-specific growth factor, Progranulin-a (Pgrn-a) during developmental neurogenesis in the embryonic retina of zebrafish. At 24 hpf pgrn-a is expressed throughout the forebrain, but by 48 hpf pgrn-a is exclusively expressed by microglia and/or microglial precursors within the brain and retina. Knockdown of Pgrn-a does not alter the onset of neurogenic programs or increase cell death, however, in its absence, neurogenesis is significantly delayed-retinal progenitors fail to exit the cell cycle at the appropriate developmental time and postmitotic cells do not acquire markers of terminal differentiation, and microglial precursors do not colonize the retina. Given the link between Progranulin and cell cycle regulation in peripheral tissues and transformed cells, we analyzed cell cycle kinetics among retinal progenitors following Pgrn-a knockdown. Depleting Pgrn-a results in a significant lengthening of the cell cycle. These data suggest that Pgrn-a plays a dual role during nervous system development by governing the rate at which progenitors progress through the cell cycle and attracting microglial progenitors into the embryonic brain and retina. Collectively, these data show that Pgrn-a governs neurogenesis by regulating cell cycle kinetics and the transition from proliferation to cell cycle exit and differentiation. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 77: 1114-1129, 2017. © 2017 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.

  15. CHANGES IN NEUROTRANSMITTER GENE EXPRESSION IN THE AGING RETINA.

    To understand mechanisms of neurotoxicity in susceptible populations, we examined age-related changes in constitutive gene expression in the retinas of young (4mos), middle-aged (11 mos) and aged (23 mos) male Long Evans rats. Derived from a pouch of the forebrain during develop...

  16. Eye Controlled Simulation of Scotoma Effects on the Retina

    1990-07-01

    movements since the central region of the viewing. The PRLs were positioned near the retina, the macula , and its center, the fovea, have scotoma boundary...scotoma area; as macular degeneration increases in size. near to the fovea as possible to maximize acuity, Feedback of failures to detect targets might

  17. Near UV radiation effect on the lens and retina

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  18. A digital retina-like low-level vision processor.

    Mertoguno, S; Bourbakis, N G

    2003-01-01

    This correspondence presents the basic design and the simulation of a low level multilayer vision processor that emulates to some degree the functional behavior of a human retina. This retina-like multilayer processor is the lower part of an autonomous self-organized vision system, called Kydon, that could be used on visually impaired people with a damaged visual cerebral cortex. The Kydon vision system, however, is not presented in this paper. The retina-like processor consists of four major layers, where each of them is an array processor based on hexagonal, autonomous processing elements that perform a certain set of low level vision tasks, such as smoothing and light adaptation, edge detection, segmentation, line recognition and region-graph generation. At each layer, the array processor is a 2D array of k/spl times/m hexagonal identical autonomous cells that simultaneously execute certain low level vision tasks. Thus, the hardware design and the simulation at the transistor level of the processing elements (PEs) of the retina-like processor and its simulated functionality with illustrative examples are provided in this paper.

  19. Functional Architecture of the Retina: Development and Disease

    Hoon, Mrinalini; Okawa, Haruhisa; Santina, Luca Della; Wong, Rachel O.L.

    2014-01-01

    Structure and function are highly correlated in the vertebrate retina, a sensory tissue that is organized into cell layers with microcircuits working in parallel and together to encode visual information. All vertebrate retinas share a fundamental plan, comprising five major neuronal cell classes with cell body distributions and connectivity arranged in stereotypic patterns. Conserved features in retinal design have enabled detailed analysis and comparisons of structure, connectivity and function across species. Each species, however, can adopt structural and/or functional retinal specializations, implementing variations to the basic design in order to satisfy unique requirements in visual function. Recent advances in molecular tools, imaging and electrophysiological approaches have greatly facilitated identification of the cellular and molecular mechanisms that establish the fundamental organization of the retina and the specializations of its microcircuits during development. Here, we review advances in our understanding of how these mechanisms act to shape structure and function at the single cell level, to coordinate the assembly of cell populations, and to define their specific circuitry. We also highlight how structure is rearranged and function is disrupted in disease, and discuss current approaches to re-establish the intricate functional architecture of the retina. PMID:24984227

  20. The effects of microwave radiation on rabbit's retina

    Mohammad R. Talebnejad

    2018-03-01

    Conclusions: Histopathologically, cell phone simulated MW irradiation had no significant detrimental effect on the retina. However, ciliary body congestion was observed in greater fraction of those who received higher MW doses. Although there was no significant difference between post-treatment mean ERG values, there were statistically non-significant trends toward greater changes in the MW irradiated eyes.

  1. GABA sensitivity of spectrally classified horizontal cells in goldfish retina

    Verweij, J.; Kamermans, M.; Negishi, K.; Spekreijse, H.

    1998-01-01

    We studied the GABA sensitivity of horizontal cells in the isolated goldfish retina. After the glutamatergic input to the horizontal cells was blocked with DNQX, GABA depolarized the monophasic and biphasic horizontal cells. The pharmacology of these GABA-induced depolarizations was tested with the

  2. Localization and characterization of immunocompetent cells in the human retina

    Yang, P.; Das, P. K.; Kijlstra, A.

    2000-01-01

    Recent studies have shown that experimental uveitis can be induced by the appropriate administration of various retinal antigens. Little is known about the in-situ interactions between immune cells in the retina as a prerequisite for understanding the mechanisms involving the presentation of

  3. Why has Nature Chosen Lutein and Zeaxanthin to Protect the Retina?

    Widomska, Justyna; Subczynski, Witold K

    2014-01-01

    Age-related macular degeneration (AMD) is associated with a low level of macular carotenoids in the eye retina. Only two carotenoids, namely lutein and zeaxanthin are selectively accumulated in the human eye retina from blood plasma where more than twenty other carotenoids are available. The third carotenoid which is found in the human retina, meso-zeaxanthin is formed directly in the retina from lutein. All these carotenoids, named also macular xanthophylls, play key roles in eye health and ...

  4. Fate of labelled allitin in bean plant and mosquito

    Banerji, A.; Chintalwar, G.J.; Ramakrishnan, V.

    1980-01-01

    Allitin, the insecticidal principle of garlic (Allium sativum L) is a mixture of diallyl di- and tri-sulfides. 35 S-labelled allitin has been synthesised using different methods and used for the evaluation of its persistence in water. Results of these experiments showed that allitin has low persistence; more than 80% of the initial radioactivity was lost in 24 hr. when an aqueous emulsion of labelled allitin was exposed under the laboratory conditions. Fate of labelled allitin was studied in larvae and pupae of mosquitoes, Culex pipiens quinquefasciatus Say. Assimilation of allitin was found to be faster in larva compared to pupa. Intake of allitin by bean plant was also studied. Implications of the results obtained in the above experiments will be discussed. (author)

  5. Filarial worms reduce Plasmodium infectivity in mosquitoes.

    Matthew T Aliota

    2011-02-01

    Full Text Available Co-occurrence of malaria and filarial worm parasites has been reported, but little is known about the interaction between filarial worm and malaria parasites with the same Anopheles vector. Herein, we present data evaluating the interaction between Wuchereria bancrofti and Anopheles punctulatus in Papua New Guinea (PNG. Our field studies in PNG demonstrated that An. punctulatus utilizes the melanization immune response as a natural mechanism of filarial worm resistance against invading W. bancrofti microfilariae. We then conducted laboratory studies utilizing the mosquitoes Armigeres subalbatus and Aedes aegypti and the parasites Brugia malayi, Brugia pahangi, Dirofilaria immitis, and Plasmodium gallinaceum to evaluate the hypothesis that immune activation and/or development by filarial worms negatively impact Plasmodium development in co-infected mosquitoes. Ar. subalbatus used in this study are natural vectors of P. gallinaceum and B. pahangi and they are naturally refractory to B. malayi (melanization-based refractoriness.Mosquitoes were dissected and Plasmodium development was analyzed six days after blood feeding on either P. gallinaceum alone or after taking a bloodmeal containing both P. gallinaceum and B. malayi or a bloodmeal containing both P. gallinaceum and B. pahangi. There was a significant reduction in the prevalence and mean intensity of Plasmodium infections in two species of mosquito that had dual infections as compared to those mosquitoes that were infected with Plasmodium alone, and was independent of whether the mosquito had a melanization immune response to the filarial worm or not. However, there was no reduction in Plasmodium development when filarial worms were present in the bloodmeal (D. immitis but midgut penetration was absent, suggesting that factors associated with penetration of the midgut by filarial worms likely are responsible for the observed reduction in malaria parasite infections.These results could have an

  6. Evaluating the effects of mosquito control adulticides on honey bees

    While mosquito control adulticides can be effective in rapidly reducing mosquito populations during times of high arbovirus transmission, the impacts of these control measures on pollinators has been of recent interest. The purpose of our study was to evaluate mosquito and honey bee mortality using ...

  7. Analysis of Culex and Aedes mosquitoes in southwestern Nigeria ...

    Introduction: Amplification and transmission of West Nile virus (WNV) by mosquitoes are driven by presence and number of viraemic/susceptible avian hosts. Methods: in order to predict risk of WNV infection to humans, we collected mosquitoes from horse stables in Lagos and Ibadan, southwestern Nigeria. The mosquitoes ...

  8. Rift Valley fever potential mosquito vectors and their infection status ...

    Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease. Rift Valley fever virus (RVFV) has been isolated from more than 40 species of mosquitoes from eight genera. This study was conducted to determine the abundance of potential mosquito vectors and their RVFV infection status in Ngorongoro ...

  9. Plasmodium ookinetes coopt mammalian plasminogen to invade the mosquito midgut

    Ghosh, Anil K; Coppens, Isabelle; Gårdsvoll, Henrik

    2011-01-01

    Ookinete invasion of the mosquito midgut is an essential step for the development of the malaria parasite in the mosquito. Invasion involves recognition between a presumed mosquito midgut receptor and an ookinete ligand. Here, we show that enolase lines the ookinete surface. An antienolase antibody...

  10. Spontaneous activity in the developing mammalian retina: Form and function

    Butts, Daniel Allison

    Spontaneous neuronal activity is present in the immature mammalian retina during the initial stages of visual system development, before the retina is responsive to light. This activity consists of bursts of action potentials fired by retinal ganglion cells, and propagates in a wavelike manner across the inner plexiform layer of the retina. Unlike waves in other neural systems, retinal waves have large variability in both their rate and direction of propagation, and individual waves only propagate across small regions of the retina. The unique properties of retinal activity arise from dynamic processes within the developing retina, and produce characteristic spatiotemporal properties. These spatiotemporal properties are of particular interest, since they are believed to play a role in visual system development. This dissertation addresses the complex spatiotemporal patterning of the retinal waves from two different perspectives. First, it proposes how the immature circuitry of the developing retina generates these patterns of activity. In order to reproduce the distinct spatiotemporal properties observed in experiments, a model of the immature retinal circuitry must meet certain requirements, which are satisfied by a coarse-grained model of the developing retina that we propose. Second, this dissertation addresses how the particular spatiotemporal patterning of the retinal waves provides information to the rest of the visual system and, as a result, can be used to guide visual system development. By measuring the properties of this information, we place constraints on the developmental mechanisms that use this activity, and show how the particular spatiotemporal properties of the retinal waves provide this information. Together, this dissertation demonstrates how the apparent complexity of retinal wave patterning can be understood both through the immature circuitry that generates it, and through the developmental mechanisms that may use it. The first three

  11. Zika Virus and Transgenic Mosquitoes: Potentials of a Public Health Tool

    Ike Val Iyioke

    2017-01-01

    Full Text Available With transgenic mosquitoes now being deployed as a major solution to the pandemic Zika virus disease, more curious questions have arisen about this public health technology. This essay reviews the philosophical considerations that presaged the development, by WHO, of the genetically modified mosquitoes. It focuses more specifically on the inter-disciplinary approach in formulating the clinical trials process. While it is still early to determine the full merits of this health intervention tool, it is nonetheless timely to examine the rich vein of form that constitutes the clinical trial protocol. I argue that the steps it suggests should be a gold standard for all clinical trial procedures including those that use human subjects and those with both direct and indirect environmental implications. Also, the early signs portend that its application could indeed be widespread. For instance, malaria and dengue fever were the original targets, but now the development of transgenic mosquito technology is deemed a potent option in the fight against Zika virus disease. In addition, this clinical trial protocol has remarkably gone beyond the four pillars of principlism to recognize the possibility that a new technology (such as GMM, can have the potential to simultaneously impact human individuals, the community and the ecosystem in tandem. In “Guidance framework for testing of genetically modified mosquito,” the WHO has set an example that calls for emulation. With the right awareness, biomedical researchers, scholars, policy makers, and students stand to benefit immensely from this reformulated approach.

  12. Abundância de culicídeos em área metropolitana preservada e suas implicações epidemiológicas Culicidae mosquito abundance in a preserved metropolitan area and its epidemiological implications

    Carmen Beatriz Taipe-Lagos

    2003-06-01

    Full Text Available OBJETIVO: Estudar a fauna de culicídeos adultos em uma área de reserva na periferia urbana para definir as espécies de interesse em saúde pública. MÉTODOS: O estudo foi realizado no Parque Ecológico do Tietê, localizado na periferia urbana da Grande São Paulo, Brasil. Realizaram-se coletas mensais em três locais e horários distintos, com o uso de aspiradores elétricos, armadilhas CDC e de Shannon no período de agosto de 1996 até março de 1998. O tratamento dos dados baseou-se na estimativa de freqüências e abundâncias. RESULTADOS: Coletaram-se 53.496 exemplares, tendo sido reconhecidas 25 espécies ou grupos genéricos. As espécies Ochlerotatus scapularis, Culex quinquefasciatus e Culex declarator foram as mais freqüentes e abundantes. CONCLUSÕES: As espécies mais freqüentes e abundantes têm demonstrado eficiência na transmissão de agentes patogênicos ao homem em outras regiões. Atenção deve ser dada a esses culicídeos, pois o o local investigado, ao lado de um complexo urbano, reúne condições favoráveis à disseminação de doenças por vetores.OBJECTIVE: To study the adult Culicidae fauna in a preserved area in urban outskirts for describing species of public health concern. METHODS: This study was developed in the Tietê Ecological Park located in the outskirt of the city of São Paulo, Brazil. Monthly collections were undertaken in three habitats at different times using electric aspirators and CDC and Shannon traps from August 1996 to March 1998. Data analysis was based on estimates of frequencies and abundance. RESULTS: Twenty-five species or generic groups were identified among 53,496 specimens collected. Ochlerotatus scapularis, Culex quinquefasciatus, and Culex declarator were the most frequent and abundant species. CONCLUSIONS: The most frequent and abundant species have been implicated in disease transmission to man in other regions. Attention must be given to these Culicidae since the study area is

  13. Distribution of photon absorption rates across the rat retina.

    Williams, T P; Webbers, J P; Giordano, L; Henderson, R P

    1998-04-15

    1. An investigation into the distribution of light intensity across the rat retina was carried out on excised, intact rat eyes exposed to Ganzfeld illumination from a helium-neon laser (543 nm). 2. Some of the light entering the eyes exits through the sclera where its intensity can be monitored with an optical 'pick-up' that samples the intensity coming from a small region of external sclera and underlying retina. The spatial resolution of the pick-up is such that it samples light that has passed through ca 2 % of the rods in the rat eye. 3. Some of the laser light is absorbed by the rod pigment, rhodopsin, which gradually bleaches. Bleaching in the retina, in turn, causes an exponential increase in intensity emanating from the sclera. By monitoring this intensity increase, we are able to measure two important parameters in a single bleaching run: the local rhodopsin concentration and the local intensity falling on the rods. 4. With an ocular transmission photometer, we have measured both the local intensity and the local rhodopsin concentration across wide regions of rat retina. Both pigmented and albino rats were studied. 5. The distributions of rhodopsin and intensity were both nearly uniform; consequently, the product, (rhodopsin concentration) x (intensity), was similarly nearly equal across the retina. This means that the initial rate of photon absorption is about the same at all retinal locations. 6. Interpreted in terms of photostasis (the regulation of daily photon catch), this means that the rate of photon absorption is about the same in each rod, viz. 14 400 photons absorbed per rod per second. Since this rate of absorption is sufficient to saturate the rod, one possible purpose of photostasis is to maintain the rod system in a saturated state during daylight hours.

  14. Impact of bronchopulmonary dysplasia on brain and retina

    Annie Wing Hoi Poon

    2016-04-01

    Full Text Available Many premature newborns develop bronchopulmonary dysplasia (BPD, a chronic lung disease resulting from prolonged mechanical ventilation and hyperoxia. BPD survivors typically suffer long-term injuries not only to the lungs, but also to the brain and retina. However, currently it is not clear whether the brain and retinal injuries in these newborns are related only to their prematurity, or also to BPD. We investigated whether the hyperoxia known to cause histologic changes in the lungs similar to BPD in an animal model also causes brain and retinal injuries. Sprague Dawley rat pups were exposed to hyperoxia (95% O2, ‘BPD’ group or room air (21% O2, ‘control’ group from postnatal day 4–14 (P4–14; the rat pups were housed in room air between P14 and P28. At P28, they were sacrificed, and their lungs, brain, and eyes were extracted. Hematoxylin and eosin staining was performed on lung and brain sections; retinas were stained with Toluidine Blue. Hyperoxia exposure resulted in an increased mean linear intercept in the lungs (P<0.0001. This increase was associated with a decrease in some brain structures [especially the whole-brain surface (P=0.02], as well as a decrease in the thickness of the retinal layers [especially the total retina (P=0.0008], compared to the room air control group. In addition, a significant negative relationship was observed between the lung structures and the brain (r=−0.49, P=0.02 and retina (r=−0.70, P=0.0008 structures. In conclusion, hyperoxia exposure impaired lung, brain, and retina structures. More severe lung injuries correlated with more severe brain and retinal injuries. This result suggests that the same animal model of chronic neonatal hyperoxia can be used to simultaneously study lung, brain and retinal injuries related to hyperoxia.

  15. Effect of chronic administration of sildenafil citrate (Viagra) on the histology of the retina and optic nerve of adult male rat.

    Eltony, Sohair A; Abdelhameed, Sally Y

    2017-04-01

    Abnormal vision has been reported by 3% of patients treated with sildenafil citrate (Viagra). Although many men use Viagra for an extended period for treatment of erectile dysfunction, the implications of the long term-daily use of it on the retina and optic nerve are unclear. To investigate the effect of chronic daily use of sildenafil citrate in a dose equivalent to men preferred therapeutic dose on the histology of the retina and optic nerve of adult male rat. Eighteen adult male Wistar rats were equally divided into three groups. Group I: control. Group II: treated with sildenafil citrate orally (10mg/kg/day) for 8 weeks. Group III (withdrawal): treated as group II and then left for 4 weeks without treatment. Specimens from the retina and optic nerve were processed for light and electron microscopy. In sildenafil citrate treated group, the retina and optic nerve revealed vacuolations and congested blood capillaries with apoptotic endothelial and pericytic cells, and thickened basal lamina. Caspase-3 (apoptotic marker) and CD31 (endothelial marker) expression increased. Glial cells revealed morphological changes: Müller cells lost their processes, activated microglia, astrocytic clasmatodendrosis, degenerated oligodendrocytes surrounded by disintegrated myelin sheathes of the optic nerve fibers. The retina and optic nerve of the withdrawal group revealed less vacuolations and congestion, and partial recovery of the glial cells. Chronic treatment with sildenafil citrate (Viagra) caused toxic effect on the structure of the retina and optic nerve of the rat. Partial recovery was observed after drug withdrawal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Protection Ability Comparison of Several Mosquito Repellent Lotion Incorporated with Essential Oils of Mosquito Repellent Plants

    Pramono Putro Utomo

    2014-12-01

    Full Text Available Most mosquito repellent lotions available on the market today contain the active ingredient diethyltoluamide (DEET which is very harmful to the skin. Natural mosquito repellent research using various essential oils (geranium oil, lemon oil, citronella oil and lavender oil as the active ingredient and the addition of aloe vera gel as a moisturizer has been done on a laboratory scale. The purpose of this study was to compare the protection ability of the mosquito repellent plants in Indonesia. The results showed that geranium oil, lemongrass oil, lavender oil and lemon oil could act as mosquito repellent. Best lotion formula all containing 15% essential oils have the effectiveness above 50% until the sixth hour were geranium oil, citronella oil and lavender oil while lemon oil only giving effectiveness above 50% until the second hour.

  17. Standard anatomical and visual space for the mouse retina: computational reconstruction and transformation of flattened retinae with the Retistruct package.

    David C Sterratt

    Full Text Available The concept of topographic mapping is central to the understanding of the visual system at many levels, from the developmental to the computational. It is important to be able to relate different coordinate systems, e.g. maps of the visual field and maps of the retina. Retinal maps are frequently based on flat-mount preparations. These use dissection and relaxing cuts to render the quasi-spherical retina into a 2D preparation. The variable nature of relaxing cuts and associated tears limits quantitative cross-animal comparisons. We present an algorithm, "Retistruct," that reconstructs retinal flat-mounts by mapping them into a standard, spherical retinal space. This is achieved by: stitching the marked-up cuts of the flat-mount outline; dividing the stitched outline into a mesh whose vertices then are mapped onto a curtailed sphere; and finally moving the vertices so as to minimise a physically-inspired deformation energy function. Our validation studies indicate that the algorithm can estimate the position of a point on the intact adult retina to within 8° of arc (3.6% of nasotemporal axis. The coordinates in reconstructed retinae can be transformed to visuotopic coordinates. Retistruct is used to investigate the organisation of the adult mouse visual system. We orient the retina relative to the nictitating membrane and compare this to eye muscle insertions. To align the retinotopic and visuotopic coordinate systems in the mouse, we utilised the geometry of binocular vision. In standard retinal space, the composite decussation line for the uncrossed retinal projection is located 64° away from the retinal pole. Projecting anatomically defined uncrossed retinal projections into visual space gives binocular congruence if the optical axis of the mouse eye is oriented at 64° azimuth and 22° elevation, in concordance with previous results. Moreover, using these coordinates, the dorsoventral boundary for S-opsin expressing cones closely matches

  18. Mosquito production from four constructed treatment wetlands in peninsular Florida.

    Rey, Jorge R; O'Meara, George F; O'Connell, Sheila M; Cutwa-Francis, Michele M

    2006-06-01

    Several techniques were used to sample adult and immature mosquitoes in 4 constructed treatment wetlands in Florida. Adults of 19 species (7 genera) of mosquitoes were collected, and immatures of the most abundant species and of 60% of all species also were collected. Few significant differences between sites and stations in the numbers of mosquitoes collected were discovered. Culex nigripalpus Theobald was the most abundant mosquito found in adult (carbon dioxide-baited suction traps) and ovitrap collections, whereas Mansonia spp. and Uranotaenia spp. were most common in pump-dip-grab samples. The roles of rooted and floating vegetation and of water quality in determining mosquito production from these areas are discussed.

  19. Cómo controlar los mosquitos en interiores (Controlling Mosquitoes Indoors)

    2016-08-23

    Los mosquitos pueden portar virus como el del Nilo Occidental o del Zika. En este podcast, Don Francisco le muestra a sus vecinos formas en las que pueden reducir el número de mosquitos dentro de su casa.  Created: 8/23/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/23/2016.

  20. Malaria mosquitoes attracted by fatal fungus.

    Justin George

    Full Text Available Insect-killing fungi such as Beauveria bassiana are being evaluated as possible active ingredients for use in novel biopesticides against mosquito vectors that transmit malaria. Fungal pathogens infect through contact and so applications of spores to surfaces such as walls, nets, or other resting sites provide possible routes to infect mosquitoes in and around domestic dwellings. However, some insects can detect and actively avoid fungal spores to reduce infection risk. If true for mosquitoes, such behavior could render the biopesticide approach ineffective. Here we find that the spores of B. bassiana are highly attractive to females of Anopheles stephensi, a major anopheline mosquito vector of human malaria in Asia. We further find that An. stephensi females are preferentially attracted to dead and dying caterpillars infected with B. bassiana, landing on them and subsequently becoming infected with the fungus. Females are also preferentially attracted to cloth sprayed with oil-formulated B. bassiana spores, with 95% of the attracted females becoming infected after a one-minute visit on the cloth. This is the first report of an insect being attracted to a lethal fungal pathogen. The exact mechanisms involved in this behavior remain unclear. Nonetheless, our results indicate that biopesticidal formulations comprising B. bassiana spores will be conducive to attraction and on-source visitation by malaria vectors.

  1. Distribution and infectivity of anopheles mosquitoes and ...

    Malaria still remains a major public health problem in Nigeria, despite serious efforts to lessen its adverse impact. A malaria survey was conducted to determine the distribution and infectivity rate of Anopheles species, and asymptomatic malaria infections in Gboko. Mosquitoes were collected at selected sites, using ...

  2. Distribution And Seasonal Abundance Of Anopheline Mosquito ...

    The essence of this study was to identify Anopheles mosquito species in Nguru, Yobe State and to determine their distribution and relative abundance in the months of the year. Insecticide and aspirator were used to collect mosqutoes in human dwellngs and preserved in 2% formalin for identcation using dissectng ...

  3. Livestock: An alternative mosquito control measure | Yakubu ...

    A survey was conducted to investigate the indigenous methods or measures adopted by urban livestock owners in the control of mosquito in Sokoto metropolis. Fifty (50) respondents who were engaged in urban livestock production were conveniently sampled, In addition, five (5) locations (Sidi farm, Kara market, Sokoto ...

  4. Cultured skin microbiota attracts malaria mosquitoes

    Verhulst, N.O.; Beijleveld, H.; Knols, B.G.J.; Takken, W.; Schraa, G.; Bouwmeester, H.J.; Smallegange, R.C.

    2009-01-01

    Background - Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human

  5. Cultured skin microbiota attracts malaria mosquitoes

    Verhulst, Niels O.; Beijleveld, Hans; Knols, Bart Gj; Takken, Willem; Schraa, Gosse; Bouwmeester, Harro J.; Smallegange, Renate C.

    2009-01-01

    Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human body odours.

  6. Cultured skin microbiota attracts malaria mosquitoes

    Verhulst, N.O.; Beijleveld, H.; Knols, B.G.J.; Takken, W.; Schraa, G.; Bouwmeester, H.J.; Smallegange, R.C.

    2009-01-01

    Background: Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human

  7. Effect of ebastine on mosquito bites.

    Reunala, T; Brummer-Korvenkontio, H; Petman, L; Palosuo, T; Sarna, S

    1997-07-01

    Mosquito bites usually cause wealing and delayed bite papules. Cetirizine decreases wealing, bite papules and pruritus but the effect of other antihistamines on mosquito bites is unknown. We studied the effect of ebastine in 30 mosquito bite-sensitive adult subjects. Ebastine 10 mg or 20 mg and placebo were given for 4 days in a cross-over fashion. Aedes aegypti bites were given on forearms. The size of the bite lesions and pruritus (visual analogue score) were measured at 15 min, 2, 6, and 24 h after the bites. Twenty-five subjects were evaluable in the study. At 15 min ebastine decreased significantly the size of the bite lesion (p = 0.0017) and pruritus (ptime points were compiled the size of the bite lesion and pruritus score decreased significantly. Sedation occurred during ebastine treatment in 6 (21%) and during placebo treatment in 2 (7%) subjects. The present results show that prophylactically given ebastine is effective against immediate mosquito bite symptoms.

  8. Mosquito repellency of novel Trifluoromethylphenyl amides

    Human diseases caused by mosquito-transmitted pathogens include malaria, dengue and yellow fever and are responsible for several million human deaths every year, according to the World Health Organization (WHO). Our current research projects focus on the development of new insecticides and repellent...

  9. Musings on Sketches, Artists, and Mosquito Nets

    2014-09-23

    Byron Breedlove reads his essay Musings on Sketches, Artists, and Mosquito Nets about the art of James Whistler and the transmission of vector borne diseases.  Created: 9/23/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/20/2014.

  10. Influence of trap construction on mosquito capture

    Šebesta, Oldřich; Peško, Juraj; Gelbič, Ivan

    2012-01-01

    Roč. 6, č. 2 (2012), s. 209-215 ISSN 1934-7391 R&D Projects: GA MŠk 2B08003 Institutional research plan: CEZ:AV0Z50070508 Institutional support: RVO:68081766 ; RVO:60077344 Keywords : CDC miniature light traps * baited lard-can traps * mosquitoes Subject RIV: EG - Zoology

  11. A global assembly of adult female mosquito mark-release-recapture data to inform the control of mosquito-borne pathogens

    Guerra, C.A.; Reiner Jr, R.C.; Perkins, T.A.; Lindsay, S.W.; Midega, J.T.; Brady, O.J.; Barker, C.M.; Reisen, W.K.; Harrington, L.C.; Takken, W.; Kitron, U.; Lloyd, A.L.; Hay, S.I.; Scott, T.W.; Smith, D.L.

    2014-01-01

    Background Pathogen transmission by mosquitos is known to be highly sensitive to mosquito bionomic parameters. Mosquito mark-release-recapture (MMRR) experiments are a standard method for estimating such parameters including dispersal, population size and density, survival, blood feeding frequency

  12. Nest Mosquito Trap quantifies contact rates between nesting birds and mosquitoes.

    Caillouët, Kevin A; Riggan, Anna E; Rider, Mark; Bulluck, Lesley P

    2012-06-01

    Accurate estimates of host-vector contact rates are required for precise determination of arbovirus transmission intensity. We designed and tested a novel mosquito collection device, the Nest Mosquito Trap (NMT), to collect mosquitoes as they attempt to feed on unrestrained nesting birds in artificial nest boxes. In the laboratory, the NMT collected nearly one-third of the mosquitoes introduced to the nest boxes. We then used these laboratory data to estimate our capture efficiency of field-collected bird-seeking mosquitoes collected over 66 trap nights. We estimated that 7.5 mosquitoes per trap night attempted to feed on nesting birds in artificial nest boxes. Presence of the NMT did not have a negative effect on avian nest success when compared to occupied nest boxes that were not sampled with the trap. Future studies using the NMT may elucidate the role of nestlings in arbovirus transmission and further refine estimates of nesting bird and vector contact rates. © 2012 The Society for Vector Ecology.

  13. Terrestrial vegetation and aquatic chemistry influence larval mosquito abundance in catch basins, Chicago, USA

    Gardner Allison M

    2013-01-01

    Full Text Available Abstract Background An important determinant of mosquito-borne pathogen transmission is the spatial distribution of vectors. The primary vectors of West Nile virus (WNV in Illinois are Culex pipiens Linnaeus (Diptera: Culicidae and Culex restuans Theobald. In urban environments, these mosquitoes commonly oviposit in roadside storm water catch basins. However, use of this habitat is inconsistent, with abundance of larvae varying significantly across catch basins at a fine spatial scale. Methods We tested the hypothesis that attributes of the biotic and abiotic environment contribute to spatial and temporal variation in production of mosquito vectors, characterizing the relationship between terrestrial vegetation and aquatic chemistry and Culex abundance in Chicago, Illinois. Larvae were sampled from 60 catch basins from June 14 to October 3, 2009. Density of shrubs and 14 tree genera surrounding the basins were quantified, as well as aquatic chemistry content of each basin. Results We demonstrate that the spatial pattern of Culex abundance in catch basins is strongly influenced by environmental characteristics, resulting in significant variation across the urban landscape. Using regression and machine learning techniques, we described landscape features and microhabitat characteristics of four Chicago neighborhoods and examined the implications of these measures for larval abundance in adjacent catch basins. The important positive predictors of high larval abundance were aquatic ammonia, nitrates, and area of shrubs of height Culex during the fruit-bearing periods and early senescent periods in August and September. Conclusions This study identifies environmental predictors of mosquito production in urban environments. Because an abundance of adult Culex is integral to efficient WNV transmission and mosquitoes are found in especially high densities near larval habitats, identifying aquatic sites for Culex and landscape features that promote

  14. Modeling and Simulation of Microelectrode-Retina Interactions

    Beckerman, M

    2002-11-30

    The goal of the retinal prosthesis project is the development of an implantable microelectrode array that can be used to supply visually-driven electrical input to cells in the retina, bypassing nonfunctional rod and cone cells, thereby restoring vision to blind individuals. This goal will be achieved through the study of the fundamentals of electrical engineering, vision research, and biomedical engineering with the aim of acquiring the knowledge needed to engineer a high-density microelectrode-tissue hybrid sensor that will restore vision to millions of blind persons. The modeling and simulation task within this project is intended to address the question how best to stimulate, and communicate with, cells in the retina using implanted microelectrodes.

  15. An analog VLSI chip emulating polarization vision of Octopus retina.

    Momeni, Massoud; Titus, Albert H

    2006-01-01

    Biological systems provide a wealth of information which form the basis for human-made artificial systems. In this work, the visual system of Octopus is investigated and its polarization sensitivity mimicked. While in actual Octopus retina, polarization vision is mainly based on the orthogonal arrangement of its photoreceptors, our implementation uses a birefringent micropolarizer made of YVO4 and mounted on a CMOS chip with neuromorphic circuitry to process linearly polarized light. Arranged in an 8 x 5 array with two photodiodes per pixel, each consuming typically 10 microW, this circuitry mimics both the functionality of individual Octopus retina cells by computing the state of polarization and the interconnection of these cells through a bias-controllable resistive network.

  16. Infrared reflectance as a diagnostic adjunct for subclinical commotio retinae

    Nicholas H Andrew

    2014-01-01

    Full Text Available Commotio retinae (CR is an outer retinal disorder following blunt trauma to the eye. Histologically it is characterized by disruption of the photoreceptor outer segments (OS, typically without injury to other retinal layers. Using spectral-domain optical coherence tomography (OCT the condition is visible as hyper-reflectivity of the OS. Most cases of CR are associated with transient grey-white discoloration of the retina and are easily diagnosed clinically, but there have been reports of OCT-confirmed CR without retinal discoloration. It is likely that this subclinical variant of CR is under-recognized as the OCT features of CR are subtle. Here, we report a case of OCT-confirmed subclinical CR that demonstrated prominent infrared hypo-reflectance, using the infrared protocol of the SPECTRALIS® OCT, Heidelberg Engineering. This case suggests that infrared reflectance may have a role in diagnosing cases of subclinical CR.

  17. Erythropoetin receptor expression in the human diabetic retina

    Tsang Stephen H

    2009-11-01

    Full Text Available Abstract Background Recent evidence suggests erythropoietin (EPO and the erythropoietin receptor (EPOR may play a direct role in the pathogenesis of diabetic retinopathy. Better characterization of the EPO-EPOR signaling system in the ischemic retina may offer a new therapeutic modality for ischemic ophthalmic diseases. This study was performed to identify EPOR mRNA expression in the human diabetic eye. Findings EPOR antisense RNA probes were validated on human pancreas tissue. In the normal eye, EPOR was expressed in the retinal ganglion cell layer. Minimal expression was observed in the inner and outer nuclear layer. Under conditions of diabetic retinopathy, EPOR expression shifted to photoreceptor cells. Increased expression was also observed in the peripheral retina. Conclusion EPOR expression may be a biomarker or contribute to disease mechanisms in diabetic retinopathy.

  18. Characteristics of Aedes aegypti adult mosquitoes in rural and urban areas of western and coastal Kenya.

    Bryson Alberto Ndenga

    Full Text Available Aedes aegypti is the main vector for yellow fever, dengue, chikungunya and Zika viruses. Recent outbreaks of dengue and chikungunya have been reported in Kenya. Presence and abundance of this vector is associated with the risk for the occurrence and transmission of these diseases. This study aimed to characterize the presence and abundance of Ae. aegypti adult mosquitoes from rural and urban sites in western and coastal regions of Kenya. Presence and abundance of Ae. aegypti adult mosquitoes were determined indoors and outdoors in two western (urban Kisumu and rural Chulaimbo and two coastal (urban Ukunda and rural Msambweni sites in Kenya. Sampling was performed using quarterly human landing catches, monthly Prokopack automated aspirators and monthly Biogents-sentinel traps. A total of 2,229 adult Ae. aegypti mosquitoes were collected: 785 (35.2% by human landing catches, 459 (20.6% by Prokopack aspiration and 985 (44.2% by Biogents-sentinel traps. About three times as many Ae. aegypti mosquitoes were collected in urban than rural sites (1,650 versus 579. Comparable numbers were collected in western (1,196 and coastal (1,033 sites. Over 80% were collected outdoors through human landing catches and Prokopack aspiration. The probability of collecting Ae. aegypti mosquitoes by human landing catches was significantly higher in the afternoon than morning hours (P<0.001, outdoors than indoors (P<0.001 and in urban than rural sites (P = 0.008. Significantly more Ae. aegypti mosquitoes were collected using Prokopack aspiration outdoors than indoors (P<0.001 and in urban than rural areas (P<0.001. Significantly more mosquitoes were collected using Biogents-sentinel traps in urban than rural areas (P = 0.008 and in western than coastal sites (P = 0.006. The probability of exposure to Ae. aegypti bites was highest in urban areas, outdoors and in the afternoon hours. These characteristics have major implications for the possible transmission of arboviral

  19. Heidelberg Retina Tomograph for the Detection of Glaucoma

    Barbara Cvenkel

    2012-06-01

    Full Text Available Heidelberg Retina Tomograph (HRT is a confocal scanning laser ophthalmoscope which acquires and analyzes 3-dimensional images of the optic nerve head. The latest instrument HRT3 includes software with larger ethinic-specific normative database. This review summarizes relevant published literature on HRT in diagnosing glaucoma, detecting glaucoma progression, the diagnostic accuracy of HRT among other imaging devices and its role in clinical practice.

  20. Effects and Responses to Spaceflight in the Mouse Retina

    Zanello, Susana B.; Theriot, Corey; Westby, Christian; Boyle, Richard

    2011-01-01

    Several stress environmental factors are combined in a unique fashion during spaceflight, affecting living beings widely across their physiological systems. Recently, attention has been placed on vision changes in astronauts returning from long duration missions. Alterations include hyperoptic shift, globe flattening, choroidal folds and optic disc edema, which are probably associated with increased intracranial pressure. These observations justify a better characterization of the ocular health risks associated with spaceflight. This study investigates the impact of spaceflight on the biology of the mouse retina. Within a successful tissue sharing effort, eyes from albino Balb/cJ mice aboard STS-133 were collected for histological analysis and gene expression profiling of the retina at 1 and 7 days after landing. Both vivarium and AEM (Animal Enclosure Module) mice were used as ground controls. Oxidative stress-induced DNA damage was higher in the flight samples compared to controls on R+1, and decreased on R+7. A trend toward higher oxidative and cellular stress response gene expression was also observed on R+1 compared to AEM controls, and these levels decreased on R+7. Several genes coding for key antioxidant enzymes, namely, heme-oxygenase-1, peroxiredoxin, and catalase, were among those upregulated after flight. Likewise, NF B and TGFbeta1, were upregulated in one flight specimen that overall showed the most elevated oxidative stress markers on R+1. In addition, retinas from vivarium control mice evidenced higher oxidative stress markers, NF B and TGFbeta1, likely due to the more intense illumination in vivarium cages versus the AEM. These preliminary data suggest that spaceflight represents a source of environmental stress that translates into oxidative and cellular stress in the retina, which is partially reversible upon return to Earth. Further work is needed to dissect the contribution of the various spaceflight factors (microgravity, radiation) and to

  1. Light regulation of the insulin receptor in the retina.

    Rajala, Raju V S; Anderson, Robert E

    2003-10-01

    The peptide hormone insulin binds its cognate cell-surface receptors to activate a coordinated biochemical-signaling network and to induce intracellular events. The retina is an integral part of the central nervous system and is known to contain insulin receptors, although their function is unknown. This article, describes recent studies that link the photobleaching of rhodopsin to tyrosine phosphorylation of the insulin receptor and subsequent activation of phosphoinositide 3- kinase (PI3K). We recently found a light-dependent increase in tyrosine phosphorylation of the insulin receptor-beta-subunit (IR beta) and an increase in PI3K enzyme activity in isolated rod outer segments (ROS) and in anti-phosphotyrosine (PY) and anti-IR beta immunoprecipitates of retinal homogenates. The light effect, which was localized to photoreceptor neurons, is independent of insulin secretion. Our results suggest that light induces tyrosine phosphorylation of IR beta in outer-segment membranes, which leads to the binding of p85 through its N-terminal SH2 domain and the generation of PI-3,4,5-P3. We suggest that the physiological role of this process may be to provide neuroprotection of the retina against light damage by activating proteins that protect against stress-induced apoptosis. The studies linking PI3K activation through tyrosine phosphorylation of IR beta now provide physiological relevance for the presence of these receptors in the retina.

  2. Identification of endogenous flurophores in the layered retina

    Xu, Gaixia; Chen, Danni; Sun, Yiwen; Qu, Junle; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

    2007-05-01

    In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment epithelium cells exhibited strong autofluorescence with as emission peak of 600+/-10nm when excited with 860-nm light. The emission peak of photoreceptors was at 652+/-5nm, and the emission peak of retinal vessels layer was weak and at 640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which suggested that there wasn't only one endogenous fluorophores of tissues excited.

  3. A biochemical basis for induction of retina regeneration by antioxidants.

    Echeverri-Ruiz, Nancy; Haynes, Tracy; Landers, Joseph; Woods, Justin; Gemma, Michael J; Hughes, Michael; Del Rio-Tsonis, Katia

    2018-01-15

    The use of antioxidants in tissue regeneration has been studied, but their mechanism of action is not well understood. Here, we analyze the role of the antioxidant N-acetylcysteine (NAC) in retina regeneration. Embryonic chicks are able to regenerate their retina after its complete removal from retinal stem/progenitor cells present in the ciliary margin (CM) of the eye only if a source of exogenous factors, such as FGF2, is present. This study shows that NAC modifies the redox status of the CM, initiates self-renewal of the stem/progenitor cells, and induces regeneration in the absence of FGF2. NAC works as an antioxidant by scavenging free radicals either independently or through the synthesis of glutathione (GSH), and/or by reducing oxidized proteins through a thiol disulfide exchange activity. We dissected the mechanism used by NAC to induce regeneration through the use of inhibitors of GSH synthesis and the use of other antioxidants with different biochemical structures and modes of action, and found that NAC induces regeneration through its thiol disulfide exchange activity. Thus, our results provide, for the first time, a biochemical basis for induction of retina regeneration. Furthermore, NAC induction was independent of FGF receptor signaling, but dependent on the MAPK (pErk1/2) pathway. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Light pollution: the possible consequences of excessive illumination on retina.

    Contín, M A; Benedetto, M M; Quinteros-Quintana, M L; Guido, M E

    2016-02-01

    Light is the visible part of the electromagnetic radiation within a range of 380-780 nm; (400-700 on primates retina). In vertebrates, the retina is adapted to capturing light photons and transmitting this information to other structures in the central nervous system. In mammals, light acts directly on the retina to fulfill two important roles: (1) the visual function through rod and cone photoreceptor cells and (2) non-image forming tasks, such as the synchronization of circadian rhythms to a 24 h solar cycle, pineal melatonin suppression and pupil light reflexes. However, the excess of illumination may cause retinal degeneration or accelerate genetic retinal diseases. In the last century human society has increased its exposure to artificial illumination, producing changes in the Light/Dark cycle, as well as in light wavelengths and intensities. Although, the consequences of unnatural illumination or light pollution have been underestimated by modern society in its way of life, light pollution may have a strong impact on people's health. The effects of artificial light sources could have direct consequences on retinal health. Constant exposure to different wavelengths and intensities of light promoted by light pollution may produce retinal degeneration as a consequence of photoreceptor or retinal pigment epithelium cells death. In this review we summarize the different mechanisms of retinal damage related to the light exposure, which generates light pollution.

  5. Mosquito population regulation and larval source management in heterogeneous environments.

    David L Smith

    Full Text Available An important question for mosquito population dynamics, mosquito-borne pathogen transmission and vector control is how mosquito populations are regulated. Here we develop simple models with heterogeneity in egg laying patterns and in the responses of larval populations to crowding in aquatic habitats. We use the models to evaluate how such heterogeneity affects mosquito population regulation and the effects of larval source management (LSM. We revisit the notion of a carrying capacity and show how heterogeneity changes our understanding of density dependence and the outcome of LSM. Crowding in and productivity of aquatic habitats is highly uneven unless egg-laying distributions are fine-tuned to match the distribution of habitats' carrying capacities. LSM reduces mosquito population density linearly with coverage if adult mosquitoes avoid laying eggs in treated habitats, but quadratically if eggs are laid in treated habitats and the effort is therefore wasted (i.e., treating 50% of habitat reduces mosquito density by approximately 75%. Unsurprisingly, targeting (i.e. treating a subset of the most productive pools gives much larger reductions for similar coverage, but with poor targeting, increasing coverage could increase adult mosquito population densities if eggs are laid in higher capacity habitats. Our analysis suggests that, in some contexts, LSM models that accounts for heterogeneity in production of adult mosquitoes provide theoretical support for pursuing mosquito-borne disease prevention through strategic and repeated application of modern larvicides.

  6. Meduloepitelioma teratóide da retina: relato de caso Teratoid medulloepithelioma of the retina: case report

    Ramon Coral Ghanem

    2004-06-01

    Full Text Available O meduloepitelioma é um tumor intra-ocular congênito originário do epitélio medular primitivo que, por sua vez, é responsável pela formação do epitélio não pigmentado do corpo ciliar. Ocorre geralmente na infância, de forma unilateral, acometendo o corpo ciliar. O objetivo deste trabalho é documentar um caso raro de meduloepitelioma teratóide originário da retina. Paciente de nove anos, feminina, apresentava baixa acuidade visual (AV, estrabismo e leucocoria no olho esquerdo (OE. A AV era de 1,0 no olho direito e movimentos de mão no OE. Foi observada tumoração retrocristaliniana branco-acinzentada no OE, aparentemente subretiniana, vascularizada, de grande extensão, com alterações císticas na sua superfície. Foram realizadas tomografia de crânio e órbitas e ecografia ocular. A paciente foi submetida à enucleação com suspeita clínica de retinoblastoma. Pelo aspecto histopatológico foi feito o diagnóstico de meduloepitelioma teratóide benigno originário da retina. Na maioria dos casos apresentados na literatura o meduloepitelioma tem origem a partir do epitélio não pigmentado do corpo ciliar. No nosso caso, a neoplasia parece ter tido origem a partir da retina, já que os cortes revelaram epitélio do corpo ciliar preservado e não foi reconhecida a estrutura normal da retina. Embora o tumor apresentado neste relato tenha sido classificado como benigno, o fato de ser lesão de grandes proporções e de crescimento aparentemente recente, justifica a conduta cirúrgica empregada. O tratamento do meduloepitelioma deve objetivar a intervenção cirúrgica precoce, na tentativa de se evitar a disseminação extra-ocular.Medulloepithelioma is a congenital intraocular tumor that usually arises from the primitive medullary epithelium that is destined to form the nonpigmented ciliary epithelium of the ciliary body. It occurs most frequently in early childhood and is unilateral. This report documents a rare case of

  7. The use of mosquito nets in fisheries: A global perspective.

    Rebecca Short

    Full Text Available Free or subsidised mosquito net (MN distribution has been an increasingly important tool in efforts to combat malaria in recent decades throughout the developing world, making great strides towards eradicating this hugely detrimental disease. However, there has been increasing concern in the natural resource management and healthcare communities over alternative use of MNs, particularly in artisanal fisheries where it has been suggested they pose a threat to sustainability of fish stocks. So far, little evidence has been presented as to the global prevalence and characteristics of MN fishing, limiting global management initiatives and incentives for action across disciplines. We conducted a rapid global assessment of mosquito net fishing (MNF observations from expert witnesses living and/or working in malarial zones using an internet survey. MNF was found to be a broadly pan-tropical activity, particularly prevalent in sub-Saharan Africa. MNF is conducted using a variety of deployment methods and scales including seine nets, scoop/dip nets, set nets and traps. MNF was witnessed in a broad range of marine and freshwater habitats and was seen to exploit a wide range of taxa, with capture of juvenile fish reported in more than half of responses. Perceived drivers of MNF were closely related to poverty, revealing potentially complex and arguably detrimental livelihood and food security implications which we discuss in light of current literature and management paradigms. The key policies likely to influence future impacts of MNF are in health, regarding net distribution, and natural resource management regarding restrictions on use. We outline critical directions for research and highlight the need for a collaborative, interdisciplinary approach to development of both localised and broad-scale policy.

  8. Lack of insecticidal effect of mosquito coils containing either metofluthrin or esbiothrin on Anopheles gambiae sensu lato mosquitoes.

    Lukwa, Nzira; Chiwade, Tonderai

    2008-12-01

    Use of mosquito coils for personal protection against malaria and mosquito nuisance is advocated under mosquito and malaria control programmes. We performed field studies of mosquito coils containing either metofluthrin or esbiothrin in experimental huts situated in Kamhororo village, Gokwe district, Zimbabwe. All tests were performed on 3-5 day old reared female Anopheles gambiae sensu lato mosquitoes. The burning times were 9hr 20min for mosquito coils containing metofluthrin and 8 hr for those containing esbiothrin and the results were significantly different (p = metofluthrin was 90% and that for esbiothrin was 73.3% and the results were significantly different (p = 0.00). Mosquito coils containing metofluthrin had a mean repellence of 92.7% as compared to 85.4% for esbiothrin and the results were not significantly different (p=0.27). The protection time as required by EPA (1999) was 6 hr for mosquito coils containing metofluthrin and 5 hr for those containing esbiothrin. The mean insecticidal effect of mosquito coils containing metofluthrin was 84% as compared to 83% for those containing esbiothrin and the results were not significantly different (p = 0.56). Both mosquito formulations could not be classified as having insecticidal effect since none of them met the 95% mortality rate criteria.

  9. Neuropeptidomics of the Mosquito Aedes Aegypti

    2010-01-01

    also reported from the honey bee , A. mellifera.38 The peptidomic analysis of the CNS resulted in the unam- biguous and nearly complete identification...in the physiology and behavior of mosquitoes.1 Neuropeptides and protein hormones are produced by endocrine cells or neurons as larger precursors...hormones. These peptide messengers exert their action by binding to membrane receptors, most often to G- protein coupled receptors (GPCRs) and, to a

  10. Newer Vaccines against Mosquito-borne Diseases.

    Aggarwal, Anju; Garg, Neha

    2018-02-01

    Mosquitos are responsible for a number of protozoal and viral diseases. Malaria, dengue, Japanese encephalitis (JE) and chikungunya epidemics occur commonly all over the world, leading to marked mortality and morbidity in children. Zika, Yellow fever and West Nile fever are others requiring prevention. Environmental control and mosquito bite prevention are useful in decreasing the burden of disease but vaccination has been found to be most cost-effective and is the need of the hour. RTS,S/AS01 vaccine is the first malaria vaccine being licensed for use against P. falciparum malaria. Dengvaxia (CYD-TDV) against dengue was licensed first in Mexico in 2015. A Vero-cell derived, inactivated and alum-adjuvanted JE vaccine based on the SA14-14-2 strain was approved in 2009 in North America, Australia and various European countries. It can be used from 2 mo of age. In India, immunization is carried out in endemic regions at 1 y of age. Another inactivated Vero-cell culture derived Kolar strain, 821564XY, JE vaccine is being used in India. Candidate vaccines against dengue, chikungunya and West Nile fever are been discussed. A continued research and development of new vaccines are required for controlling these mosquito-borne diseases.

  11. Differential utilization of blood meal amino acids in mosquitoes

    Miesfeld, Roger

    2009-01-01

    Guoli Zhou, Roger MiesfeldDepartment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USAAbstract: Amino acids in the mosquito blood meal have two forms, protein-bound and plasma-free amino acids. To determine if the metabolic fate and flux of these two forms of blood meal amino acids are distinct, we fed mosquitoes eight [14C]-labeled amino acids, seven of which are essential for mosquitoes (leucine, valine, isoleucine, phenylalanine, lysine, arginine, histidine), and one th...

  12. The immune strategies of mosquito Aedes aegypti against microbial infection.

    Wang, Yan-Hong; Chang, Meng-Meng; Wang, Xue-Li; Zheng, Ai-Hua; Zou, Zhen

    2018-06-01

    Yellow fever mosquito Aedes aegypti transmits many devastating arthropod-borne viruses (arboviruses), such as dengue virus, yellow fever virus, Chikungunya virus, and Zika virus, which cause great concern to human health. Mosquito control is an effective method to block the spread of infectious diseases. Ae. aegypti uses its innate immune system to fight against arboviruses, parasites, and fungi. In this review, we briefly summarize the recent findings in the immune response of Ae. aegypti against arboviral and entomopathogenic infections. This review enriches our understanding of the mosquito immune system and provides evidence to support the development of novel mosquito control strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

    2014-01-01

    Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

  14. Vector competence of Anopheles and Culex mosquitoes for Zika virus

    Brittany L. Dodson

    2017-03-01

    Full Text Available Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

  15. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Ryan C Smith

    2014-08-01

    Full Text Available Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

  16. TOPOGRAPHIC ORGANIZATION AND SPECIALIZED AREAS IN THE RETINA OF Callopistes palluma: GANGLION CELL LAYER

    Inzunza, Oscar; Barros B., Zitta; Bravo, Hermes

    1998-01-01

    In this paper we analyze the topographic distribution and cell body size of neurons (ganglion and displaced amacrine) of layer 8 of the retina in the chilean reptile Callopistes palluma; using whole mount retinaswith nissl stain. Callopistes palluma retina has an area centralis without fovea in which the ganglion cell density amounts 20.000 cells / µm2 while the displaced amacrine neurons is about 7.000 cells / µm2. This neural density decreased gradually towards the peripheral retina. A hor...

  17. [VEGF expression in dog retina after chorioretinal venous anastomosis].

    Lu, Ning; Li, Zhihui; Sun, Xianli; Wang, Guanglu; Zhang, Feng; Peng, Xiaoyan

    2002-09-01

    To identify changes in vascular endothelial growth factor (VEGF) expression in the dog retina after laser-induced chorioretinal venous anastomosis (CRVA), in order to find out the relationship between CRVA treatment and the related neovascular complications. Immediately after branch retinal vein occlusion (BRVO) model was made in 5 eyes of 5 normal dogs, CRVA treatment was done over a small tributary vein in the drainage distribution of the occluded vein. In each eye, there were 2 - 3 treatment sites. Four to six weeks later, a repeated treatment was given if the first treatment failed to show the anastomosis. The treatment sites with successful CRVA were divided into two groups: the small laser spot group, which received one treatment and the big laser spot group, which received more than one treatment. The expression of VEGF was investigated immunohistochemically in the treatment sites with successful anastomoses and in the 5 normal fellow eyes (control). There were totally 10 successful anastomoses in the 5 experimental eyes, among which, five received one treatment and the other 5 received more than one treatment. On fundus examination, the small laser spots were round and small, and the big laser spots were large with local proliferation. VEGF immunoreactivity was absent/weak in the normal dog retina, and remained unchanged in the small laser spot group, but somewhat increased in the big laser spot group. No neovascular complications occurred. All immunostaining experiments were accompanied by proper controls and none of the negative controls showed any immunoreactivity. Proper laser treatment can induce CRVA quite safely in nonischemic dog retina, which does not cause changes in the expression of VEGF, but severe laser damage in the treatment site can cause increased VEGF expression which may be related to neovascular complications.

  18. Survey of intravitreal injection techniques among retina specialists in Israel

    Segal O

    2016-06-01

    Full Text Available Ori Segal,1,2 Yael Segal-Trivitz,1,3 Arie Y Nemet,1,2 Noa Geffen,1,2 Ronit Nesher,1,2 Michael Mimouni4 1Department of Ophthalmology, Meir Medical Center, Kfar Saba, 2The Sackler School of Medicine, Tel Aviv University, Tel Aviv, 3Department of Psychiatry, Geha Psychiatric Hospital, Petah Tikva, 4Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel Purpose: The purpose of this study was to describe antivascular endothelial growth factor intravitreal injection techniques of retinal specialists in order to establish a cornerstone for future practice guidelines. Methods: All members of the Israeli Retina Society were contacted by email to complete an anonymous, 19-question, Internet-based survey regarding their intravitreal injection techniques. Results: Overall, 66% (52/79 completed the survey. Most (98% do not instruct patients to discontinue anticoagulant therapy and 92% prescribe treatment for patients in the waiting room. Three quarters wear sterile gloves and prepare the patient in the supine position. A majority (71% use sterile surgical draping. All respondents apply topical analgesics and a majority (69% measure the distance from the limbus to the injection site. A minority (21% displace the conjunctiva prior to injection. A majority of the survey participants use a 30-gauge needle and the most common quadrant for injection is superotemporal (33%. Less than half routinely assess postinjection optic nerve perfusion (44%. A majority (92% apply prophylactic antibiotics immediately after the injection. Conclusion: The majority of retina specialists perform intravitreal injections similarly. However, a relatively large minority performs this procedure differently. Due to the extremely low percentage of complications, it seems as though such differences do not increase the risk. However, more evidence-based medicine, a cornerstone for practice guidelines, is required in order to identify the intravitreal injection techniques

  19. Instant website optimization for retina displays how-to

    Larson, Kyle J

    2013-01-01

    Written in an accessible and practical manner which quickly imparts the knowledge you want to know. As a How-to book it will use applied examples and teach you to optimize websites for retina displays. This book is for web designers and developers who are familiar with HTML, CSS, and editing graphics who would like to improve their existing website or their next web project with high-resolution images. You'll need to have a high-definition device to be able to test the examples in this book and a server to upload your code to if you're not developing it on that device.

  20. Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

    Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

    2015-04-01

    For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

  1. Transmission traits of malaria parasites within the mosquito: Genetic variation, phenotypic plasticity, and consequences for control.

    Lefevre, Thierry; Ohm, Johanna; Dabiré, Kounbobr R; Cohuet, Anna; Choisy, Marc; Thomas, Matthew B; Cator, Lauren

    2018-04-01

    Evaluating the risk of emergence and transmission of vector-borne diseases requires knowledge of the genetic and environmental contributions to pathogen transmission traits. Compared to the significant effort devoted to understanding the biology of malaria transmission from vertebrate hosts to mosquito vectors, the strategies that malaria parasites have evolved to maximize transmission from vectors to vertebrate hosts have been largely overlooked. While determinants of infection success within the mosquito host have recently received attention, the causes of variability for other key transmission traits of malaria, namely the duration of parasite development and its virulence within the vector, as well as its ability to alter mosquito behavior, remain largely unknown. This important gap in our knowledge needs to be bridged in order to obtain an integrative view of the ecology and evolution of malaria transmission strategies. Associations between transmission traits also need to be characterized, as they trade-offs and constraints could have important implications for understanding the evolution of parasite transmission. Finally, theoretical studies are required to evaluate how genetic and environmental influences on parasite transmission traits can shape malaria dynamics and evolution in response to disease control.

  2. Targeting the breeding sites of malaria mosquitoes: biological and physical control of malaria mosquito larvae

    Bukhari, S.T.

    2011-01-01


    Malaria causes an estimated 225 million cases and 781,000 deaths every year. About 85% of the deaths are in children under five years of age. Malaria is caused by the Plasmodium parasite which is transmitted by the Anopheles mosquito vector. Mainly two methods of intervention are used for

  3. An Annotated Bibliography of the Mosquitoes and Mosquito-Borne Diseases of Guam (Diptera: Culicidae)

    1976-01-01

    of elephantiasis , with 83 Americans and 28 natives admitted during the year with dengue fever, No cases of malaria were known to have originated on...group, p. 109. Mosquito Systematics Vol. 8(4) 1976 -3e *South Pacific Conmission. 1951. Conference of experts on filariasis and elephantiasis . So

  4. Experimental oral iron administration: Histological investigations and expressions of iron handling proteins in rat retina with aging.

    Kumar, Pankaj; Nag, Tapas Chandra; Jha, Kumar Abhiram; Dey, Sanjay Kumar; Kathpalia, Poorti; Maurya, Meenakshi; Gupta, Chandan Lal; Bhatia, Jagriti; Roy, Tara Sankar; Wadhwa, Shashi

    2017-12-01

    Iron is implicated in age-related macular degeneration (AMD). The aim of this study was to see if long-term, experimental iron administration with aging modifies retinal and choroidal structures and expressions of iron handling proteins, to understand some aspects of iron homeostasis. Male Wistar rats were fed with ferrous sulphate heptahydrate (500mg/kg body weight/week, oral; elemental iron availability: 20%) from 2 months of age onward until they were 19.5 month-old. At 8, 14 and 20 months of age, they were sacrificed and serum and retinal iron levels were detected by HPLC. Oxidative stress was analyzed by TBARS method. The retinas were examined for cell death (TUNEL), histology (electron microscopy) and the expressions of transferrin, transferrin receptor-1 [TFR-1], H- and L-ferritin. In control animals, at any age, there was no difference in the serum and retinal iron levels, but the latter increased significantly in 14- and 20 month-old iron-fed rats, indicating that retinal iron accumulation proceeds with progression of aging (>14 months). The serum and retinal TBARS levels increased significantly with progression of aging in experimental but not in control rats. There was significant damage to choriocapillaris, accumulation of phagosomes in retinal pigment epithelium and increased incidence of TUNEL+ cells in outer nuclear layer and vacuolation in inner nuclear layer (INL) of 20 month-aged experimental rats, compared to those in age-matched controls. Vacuolations in INL could indicate a long-term effect of iron accumulation in the inner retina. These events paralleled the increased expression of ferritins and transferrin and a decrease in the expression of TFR-1 in iron-fed rats with aging, thereby maintaining iron homeostasis in the retina. As some of these changes mimic with those happening in eyes with AMD, this model can be utilized to understand iron-induced pathophysiological changes in AMD. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Changes in expression of Class 3 Semaphorins and their receptors during development of the rat retina and superior colliculus.

    Sharma, Anil; LeVaillant, Chrisna J; Plant, Giles W; Harvey, Alan R

    2014-07-26

    Members of the Semaphorin 3 family (Sema3s) influence the development of the central nervous system, and some are implicated in regulating aspects of visual system development. However, we lack information about the timing of expression of the Sema3s with respect to different developmental epochs in the mammalian visual system. In this time-course study in the rat, we document for the first time changes in the expression of RNAs for the majority of Class 3 Semaphorins (Sema3s) and their receptor components during the development of the rat retina and superior colliculus (SC). During retinal development, transcript levels changed for all of the Sema3s examined, as well as Nrp2, Plxna2, Plxna3, and Plxna4a. In the SC there were also changes in transcript levels for all Sema3s tested, as well as Nrp1, Nrp2, Plxna1, Plxna2, Plxna3, and Plxna4a. These changes correlate with well-established epochs, and our data suggest that the Sema3s could influence retinal ganglion cell (RGC) apoptosis, patterning and connectivity in the maturing retina and SC, and perhaps guidance of RGC and cortical axons in the SC. Functionally we found that SEMA3A, SEMA3C, SEMA3E, and SEMA3F proteins collapsed purified postnatal day 1 RGC growth cones in vitro. Significantly this is a developmental stage when RGCs are growing into and within the SC and are exposed to Sema3 ligands. These new data describing the overall temporal regulation of Sema3 expression in the rat retina and SC provide a platform for further work characterising the functional impact of these proteins on the development and maturation of mammalian visual pathways.

  6. Comparison of the neuroinflammatory responses to selective retina therapy and continuous-wave laser photocoagulation in mouse eyes.

    Han, Jung Woo; Choi, Juhye; Kim, Young Shin; Kim, Jina; Brinkmann, Ralf; Lyu, Jungmook; Park, Tae Kwann

    2018-02-01

    This study investigated microglia and inflammatory cell responses after selective retina therapy (SRT) with microsecond-pulsed laser in comparison to continuous-wave laser photocoagulation (cwPC). Healthy C57BL/6 J mice were treated with either a train of short pulses (SRT; 527-nm, Q-switched, 1.7-μs pulse) or a conventional thermal continuous-wave (532-nm, 100-ms pulse duration) laser. The mice were sacrificed and their eyes were enucleated 1, 3, 7, and 14 days after both laser treatments. Pattern of cell death on retinal section was evaluated by TUNEL assay, and the distribution of activated inflammatory cells and glial cells were observed under immunohistochemistry. Consecutive changes for the expression of cytokines such as IL-1β, TNF-α, and TGF-β were also examined using immunohistochemistry, and compared among each period after quantification by Western blotting. The numbers of TUNEL-positive cells in the retinal pigment epithelium (RPE) layer did not differ in SRT and cwPC lesions, but TUNEL-positive cells in neural retinas were significantly less on SRT. Vague glial cell activation was observed in SRT-treated lesions. The population of inflammatory cells was also significantly decreased after SRT, and the cells were located in the RPE layer and subretinal space. Proinflammatory cytokines, including IL-1β and TNF-α, showed significantly lower levels after SRT; conversely, the level of TGF-β was similar to the cwPC-treated lesion. SRT resulted in selective RPE damage without collateral thermal injury to the neural retina, and apparently produced negligible glial activation. In addition, SRT showed a markedly less inflammatory response than cwPC, which may have important therapeutic implications for several macular diseases.

  7. Protective effect of melatonin in the diabetic rat retina.

    Mehrzadi, Saeed; Motevalian, Manijeh; Rezaei Kanavi, Mozhgan; Fatemi, Iman; Ghaznavi, Habib; Shahriari, Mansoor

    2018-03-01

    Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes. The aim of this study was to evaluate the effects of melatonin (MEL) on retinal injury in diabetic rats. In this study, 21 rats were randomly divided into three groups: control, diabetic, and diabetic + MEL. Streptozotocin was used to induce diabetes at a dose of 50 mg/kg, i.p., and blood glucose was measured to choose the diabetic rats for the study. MEL (20 mg/kg) was given orally for 7 weeks in diabetic rats starting 1 week after induction of diabetes. After 8 weeks, the groups were compared in terms of mean scores of fluorescein leakage, using fluorescein angiography. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were estimated in retina using commercially available assays. Structural changes in retinas were evaluated by light microscopy. Results showed that diabetes significantly increased the mean scores of fluorescein leakage, and MDA and ROS levels compared to control group. Treatment of the diabetic rats with MEL for 7 weeks prevented the alterations induced by diabetes in comparison with the diabetic control group.Based on these findings, it can be concluded that MEL might have beneficial effects in prevention of DR. © 2018 Société Française de Pharmacologie et de Thérapeutique.

  8. An experimental platform for systemic drug delivery to the retina.

    Campbell, Matthew

    2009-10-20

    Degenerative retinopathies, including age-related macular degeneration, diabetic retinopathy, and hereditary retinal disorders--major causes of world blindness--are potentially treatable by using low-molecular weight neuroprotective, antiapoptotic, or antineovascular drugs. These agents are, however, not in current systemic use owing to, among other factors, their inability to passively diffuse across the microvasculature of the retina because of the presence of the inner blood-retina barrier (iBRB). Moreover, preclinical assessment of the efficacies of new formulations in the treatment of such conditions is similarly compromised. We describe here an experimental process for RNAi-mediated, size-selective, transient, and reversible modulation of the iBRB in mice to molecules up to 800 Da by suppression of transcripts encoding claudin-5, a protein component of the tight junctions of the inner retinal vasculature. MRI produced no evidence indicative of brain or retinal edema, and the process resulted in minimal disturbance of global transcriptional patterns analyzed in neuronal tissue. We show that visual function can be improved in IMPDH1(-\\/-) mice, a model of autosomal recessive retinitis pigmentosa, and that the rate of photoreceptor cell death can be reduced in a model of light-induced retinal degeneration by systemic drug delivery after reversible barrier opening. These findings provide a platform for high-throughput drug screening in models of retinal degeneration, and they ultimately could result in the development of a novel "humanized" approach to therapy for conditions with little or no current forms of treatment.

  9. Adaptive Optical System for Retina Imaging Approaches Clinic Applications

    Ling, N.; Zhang, Y.; Rao, X.; Wang, C.; Hu, Y.; Jiang, W.; Jiang, C.

    We presented "A small adaptive optical system on table for human retinal imaging" at the 3rd Workshop on Adaptive Optics for Industry and Medicine. In this system, a 19 element small deformable mirror was used as wavefront correction element. High resolution images of photo receptors and capillaries of human retina were obtained. In recent two years, at the base of this system a new adaptive optical system for human retina imaging has been developed. The wavefront correction element is a newly developed 37 element deformable mirror. Some modifications have been adopted for easy operation. Experiments for different imaging wavelengths and axial positions were conducted. Mosaic pictures of photoreceptors and capillaries were obtained. 100 normal and abnormal eyes of different ages have been inspected.The first report in the world concerning the most detailed capillary distribution images cover ±3° by ± 3° field around the fovea has been demonstrated. Some preliminary very early diagnosis experiment has been tried in laboratory. This system is being planned to move to the hospital for clinic experiments.

  10. Three dimensional reconstruction of tomographic images of the retina

    Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

    2007-01-01

    The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

  11. Finestructure of the retina in Garra rufa (cypriniae, Teleostei)

    Al-Adhami, A. M.; Mir, S.

    1999-01-01

    The light - and dark-adapted retina of the freshwater, bottom-dweller tele ost, Ga rra rufa (Heck el, 1843) was studied under light and electron microscopes. The fish is a fist record in having both falcifrom process and vit real blood circulation and the hyaloid artery from which it developers. A number of acute vision areas represented by increased density of ganglion cell soma ta are evident. The dark-adapted retina is characterized by notably large photoreceptor terminals (rod spherules and cone placidas). A rod spherules has single synaptic ribbon, whereas a cone pedicle has three to four. The inner nuclear layer is composed of the so meta of horizontal, bipolar and amsacrine cells in addition to nuclei of Muller cells. The outer nuclear layer, on the other hand, is composed of two-three rows of rod nuclei and one row of cone nuclei. The photoreceptor cells include rods and single and double cones. The rod outer segments have deep and/or shallow incisor. Cone ellipsoid may have ellipsosomes. These are shown to develop from one of the apical mitochondria of the ellipsoid- Retinomotor movement involves both the photoreceptor cells and the pigment epithelium. (authors). 11 refs., 14 figs

  12. Vsx2 in the zebrafish retina: restricted lineages through derepression

    Higashijima Shin-ichi

    2009-04-01

    Full Text Available Abstract Background The neurons in the vertebrate retina arise from multipotent retinal progenitor cells (RPCs. It is not clear, however, which progenitors are multipotent or why they are multipotent. Results In this study we show that the homeodomain transcription factor Vsx2 is initially expressed throughout the retinal epithelium, but later it is downregulated in all but a minor population of bipolar cells and all Müller glia. The Vsx2-negative daughters of Vsx2-positive RPCs divide and give rise to all other cell types in the retina. Vsx2 is a repressor whose targets include transcription factors such as Vsx1, which is expressed in the progenitors of distinct non-Vsx2 bipolars, and the basic helix-loop-helix transcription factor Ath5, which restricts the fate of progenitors to retinal ganglion cells, horizontal cells, amacrine cells and photoreceptors fates. Foxn4, expressed in the progenitors of amacrine and horizontal cells, is also negatively regulated by Vsx2. Conclusion Our data thus suggest Vsx2-positive RPCs are fully multipotent retinal progenitors and that when Vsx2 is downregulated, Vsx2-negative progenitors escape Vsx2 repression and so are able to express factors that restrict lineage potential.

  13. Flash photolysis of rhodopsin in the cat retina

    Ripps, H.; Mehaffey, L.; Siegel, I.M.; Ernst, W.; Kemp, C.M.

    1981-01-01

    The bleaching of rhodopsin by short-duration flashes of a xenon discharge lamp was studied in vivo in the cat retina with the aid of a rapid, spectral-scan fundus reflectometer. Difference spectra recorded over a broad range of intensities showed that the bleaching efficacy of high-intensity flashes was less than that of longer duration, steady lights delivering the same amount of energy. Both the empirical results and those derived from a theoretical analysis of flash photolysis indicate that, under the conditions of these experiments, the upper limit of the flash bleaching of rhodopsin in cat is approximately 90%. Although the fact that a full bleach could not be attained is attributable to photoreversal, i.e., the photic regeneration of rhodopsin from its light-sensitive intermediates, the 90% limit is considerably higher than the 50% (or lower) value obtained under other experimental circumstances. Thus, it appears that the duration (approximately 1 ms) and spectral composition of the flash, coupled with the kinetic parameters of the thermal and photic reactions in the cat retina, reduce the light-induced regeneration of rhodopsin to approximately 10%

  14. Inner neural retina loss in central retinal artery occlusion.

    Ikeda, Fumiko; Kishi, Shoji

    2010-09-01

    To report morphologic retinal changes and visual outcomes in acute and chronic central retinal artery occlusion (CRAO). We reviewed ten eyes of ten patients with CRAO (age, 65.3 ± 10.2 years) and measured retinal thicknesses at the central fovea and the perifovea using optical coherence tomography (OCT) over 8 ± 4 months. During the acute phase (within 10 days), the mean inner retinal thicknesses were 148% and 139% of normal values at 1 mm nasal and temporal to the fovea. They decreased to 22% and 11% of normal inner retinal thickness during the chronic phase (3 months or later). The retinal thickness at the perifovea decreased linearly until 3 months but was stable during the chronic phase. In contrast, the foveal thickness increased slightly in the acute phase but was equivalent to the normal level during the chronic phase. As a result of inner retinal atrophy, the foveal pit was shallow during the chronic phase. The final visual acuity was correlated positively with retinal thickness at the perifovea during the chronic CRAO phase. OCT showed that inner retinal necrosis with early swelling and late atrophy occurred in CRAO. The fovea and outer retina appeared to be excluded from ischemic change. The residual inner retina at the perifovea determined the final visual outcomes.

  15. MosquitoNet: investigating the use of UAV and artificial neural networks for integrated mosquito management

    Case, E.; Ren, Y.; Shragai, T.; Erickson, D.

    2017-12-01

    Integrated mosquito control is expensive and resource intensive, and changing climatic factors are predicted to expand the habitable range of disease-carrying mosquitoes into new regions in the United States. Of particular concern in the northeastern United States are aedes albopictus, an aggressive, invasive species of mosquito that can transmit both native and exotic disease. Ae. albopictus prefer to live near human populations and breed in artificial containers with as little as two millimeters of standing water, exponentially increasing the difficulty of source control in suburban and urban areas. However, low-cost unmanned aerial vehicles (UAVs) can be used to photograph large regions at centimeter-resolution, and can image containers of interest in suburban neighborhoods. While proofs-of-concepts have been shown using UAVs to identify naturally occurring bodies of water, they have not been used to identify mosquito habitat in more populated areas. One of the primary challenges is that post-processing high-resolution aerial imagery is still time intensive, often labelled by hand or with programs built for satellite imagery. Artificial neural networks have been highly successful at image recognition tasks; in the past five years, convolutional neural networks (CNN) have surpassed or aided trained humans in identification of skin cancer, agricultural crops, and poverty levels from satellite imagery. MosquitoNet, a dual classifier built from the Single Shot Multibox Detector and VGG16 architectures, was trained on UAV­­­­­ aerial imagery taken during a larval study in Westchester County in southern New York State in July and August 2017. MosquitoNet was designed to assess the habitat risk of suburban properties by automating the identification and counting of containers like tires, toys, garbage bins, flower pots, etc. The SSD-based architecture marked small containers and other habitat indicators while the VGG16-based architecture classified the type of

  16. Extractos del diario de un mosquito moderno

    Jesse B. Leslie

    1943-01-01

    que desempeñamos en la guerra con España. Matamos más soldados y produjimos más enfermedades, penalidades y devastación en el ejército que las mismas balas. No cabe duda de que nuestra reputación como combatientes es internacional y digna de la primera página de los diarios. ¿ En honor de quién y por qué creen ustedes que se bautizaron los botes y las flotas "Mosquito"?

  17. Does polyandrous impede mosquito control by autocidal?

    K.Jayaprakash

    2014-03-01

    Full Text Available Vector mosquito control by releasing genetically altered males has been attempted under the presumption that the females are monandrous. The present observation was through the sex–linked inheritance pattern of eye-colour and the estimation of polyandrous in in-vitro mating. A small proportion (18.2% of the female Anopheles stephensi population exhibited polyandrous on examination of 850 F1 adults when two types of males (white and black eyed where allowed to mate with homozygous white eyed females. The above results were discussed with relation to the consequences of the polyandrous trait in sterile insect technique, genetic control programmes.

  18. Crowdsourcing for large-scale mosquito (Diptera: Culicidae) sampling

    Sampling a cosmopolitan mosquito (Diptera: Culicidae) species throughout its range is logistically challenging and extremely resource intensive. Mosquito control programmes and regional networks operate at the local level and often conduct sampling activities across much of North America. A method f...

  19. Mass mosquito trapping for malaria control in western Kenya

    Hiscox, Alexandra; Homan, Tobias; Mweresa, Collins K.; Maire, Nicolas; Pasquale, Di Aurelio; Masiga, Daniel; Oria, Prisca A.; Alaii, Jane; Leeuwis, Cees; Mukabana, Wolfgang R.; Takken, Willem; Smith, Thomas A.

    2016-01-01

    Background: Increasing levels of insecticide resistance as well as outdoor, residual transmission of malaria threaten the efficacy of existing vector control tools used against malaria mosquitoes. The development of odour-baited mosquito traps has led to the possibility of controlling malaria

  20. Quantifying impact of mosquitoes on quality of life

    New Jersey, like many eastern states, has a persistent problem of the Asian tiger mosquito. This and other mosquitoes reduce residents’ quality of life from discomfort and possible risk of disease. To guide a comprehensive area-wide pest management project to control Aedes albopictus in two counties...

  1. Advances in insect physiology. Progress in mosquito research

    This book review briefly summarizes the most interesting topics/chapters from the book: "Advances in Insect Physiology: Progress in mosquito Research". The book is an excellent overview of the recent advances in mosquito biology. This volume encompasses 13 chapters from 32 contributing authors who ...

  2. Mosquito fauna of a tropical museum and zoological garden complex

    The mosquito fauna of Museum and Zoological Garden Complex (JZC), a major tourist attraction inJos Metropolis of Nigeria, was studied The choice of the complex was out of public health curiosity. A total of 627 mosquitoes comprising 4 genera, Aedes, Culex, Coquilletidia and Eretmapodites, and9 species were caught n ...

  3. Insecticide susceptibility status of human biting mosquitoes in ...

    Background: There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This situation presents a challenge to chemicals that are currently used to control mosquitoes in sub-Saharan African. Furthermore, there is limited information on insecticide ...

  4. Mosquitoes as vectors of human disease in South Africa | Jupp ...

    While malaria is the most important mosquito-borne disease in South Africa, there are also several mosquito-borne viruses that also cause human disease. The most significant are chikungunya, West Nile, Sindbis and Rift Valley fever viruses. In this review these are compared with malaria, mainly in regard to their ecology ...

  5. Relative abundance of mosquito species in Katsina Metropolis ...

    A study was conducted on the relative abundance of mosquito species, around selected areas of Katsina metropolis, Katsina State, Nigeria during the months of January, February, April and June 2010. Mosquitoes were collected from five sampling sites: Kofar Durbi, Kofar Kaura, Kofar Marusa, GRA and Layout. These were ...

  6. Mosquito bite anaphylaxis: immunotherapy with whole body extracts.

    McCormack, D R; Salata, K F; Hershey, J N; Carpenter, G B; Engler, R J

    1995-01-01

    Adverse reactions to mosquito bites have been recognized for some time. These usually consist of large local swellings and redness, generalized urticaria, angioedema and less easily definable responses such as nausea, dizziness, headaches, and lethargy. We report two patients who experienced systemic anaphylaxis from mosquito bites. Both were skin tested and given immunotherapy using whole body mosquito extracts. Skin testing using whole body mosquito extracts was positive to Aedes aegypti at 1/1,000 weight/volume (wt/vol) in one patient and to Aedes aegypti at 1/100,000 wt/vol, and Culex pipiens at 1/10,000 wt/vol in the other. Skin testing of ten volunteers without a history of adverse reactions to mosquito bites was negative. Immunotherapy using these extracts resulted in resolution of adverse reactions to mosquito bites in one patient and a decrease in reactions in the other. Immunotherapy with whole body mosquito extracts is a viable treatment option that can play a role in patients with mosquito bite-induced anaphylaxis. It may also result in severe side effects and one must determine the benefit versus risks for each individual patient.

  7. An entomopathogenic fungus for control of adult African malaria mosquitoes

    Scholte, E.J.; Ng'habi, K.R.N.; Kihonda, J.; Takken, W.; Paaijmans, K.P.; Abdulla, S.; Killeen, G.F.; Knols, B.G.J.

    2005-01-01

    Biological control of malaria mosquitoes in Africa has rarely been used in vector control programs. Recent developments in this field show that certain fungi are virulent to adult Anopheles mosquitoes. Practical delivery of an entomopathogenic fungus that infected and killed adult Anopheles gambiae,

  8. Adult vector control, mosquito ecology and malaria transmission.

    Brady, Oliver J; Godfray, H Charles J; Tatem, Andrew J; Gething, Peter W; Cohen, Justin M; McKenzie, F Ellis; Alex Perkins, T; Reiner, Robert C; Tusting, Lucy S; Scott, Thomas W; Lindsay, Steven W; Hay, Simon I; Smith, David L

    2015-03-01

    Standard advice regarding vector control is to prefer interventions that reduce the lifespan of adult mosquitoes. The basis for this advice is a decades-old sensitivity analysis of 'vectorial capacity', a concept relevant for most malaria transmission models and based solely on adult mosquito population dynamics. Recent advances in micro-simulation models offer an opportunity to expand the theory of vectorial capacity to include both adult and juvenile mosquito stages in the model. In this study we revisit arguments about transmission and its sensitivity to mosquito bionomic parameters using an elasticity analysis of developed formulations of vectorial capacity. We show that reducing adult survival has effects on both adult and juvenile population size, which are significant for transmission and not accounted for in traditional formulations of vectorial capacity. The elasticity of these effects is dependent on various mosquito population parameters, which we explore. Overall, control is most sensitive to methods that affect adult mosquito mortality rates, followed by blood feeding frequency, human blood feeding habit, and lastly, to adult mosquito population density. These results emphasise more strongly than ever the sensitivity of transmission to adult mosquito mortality, but also suggest the high potential of combinations of interventions including larval source management. This must be done with caution, however, as policy requires a more careful consideration of costs, operational difficulties and policy goals in relation to baseline transmission. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

  9. Environmental statistical modelling of mosquito vectors at different geographical scales

    Cianci, D.

    2015-01-01

    Vector-borne diseases are infections transmitted by the bite of infected arthropod vectors, such as mosquitoes, ticks, fleas, midges and flies. Vector-borne diseases pose an increasingly wider threat to global public health, both in terms of people affected and their geographical spread. Mosquitoes

  10. UV light and urban pollution: Bad cocktail for mosquitoes?

    Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud’homme, Sophie M.; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane

    2014-01-01

    Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on

  11. UV light and urban pollution: Bad cocktail for mosquitoes?

    Tetreau, Guillaume, E-mail: guillaume.tetreau@gmail.com [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France); Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456 (United States); Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud’homme, Sophie M.; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane [Laboratoire d’Ecologie Alpine, LECA-UMR 5553, Université de Grenoble 1, BP 53, 38041 Grenoble cedex 09 (France)

    2014-01-15

    Highlights: •Mosquito tolerance to temephos is induced by PAHs and UV exposure. •Toxicity of fluoranthene for mosquito Malpighian tubules cells is induced by UV. •Fluoranthene crystallizes in mosquito Malpighian tubules upon UV exposure. •Mixture of two PAHs is less toxic for mosquitoes than each PAHs separately. •Combination of abiotic parameters (PAHs and UV) affect mosquito physiology. -- Abstract: Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species–ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis–Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on

  12. Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

    Molina-Cruz, Alvaro; Zilversmit, Martine M; Neafsey, Daniel E; Hartl, Daniel L; Barillas-Mury, Carolina

    2016-11-23

    Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.

  13. Mosquito transmission of the rodent malaria parasite Plasmodium chabaudi

    Spence Philip J

    2012-12-01

    Full Text Available Abstract Background Serial blood passage of Plasmodium increases virulence, whilst mosquito transmission inherently regulates parasite virulence within the mammalian host. It is, therefore, imperative that all aspects of experimental malaria research are studied in the context of the complete Plasmodium life cycle. Methods Plasmodium chabaudi chabaudi displays many characteristics associated with human Plasmodium infection of natural mosquito vectors and the mammalian host, and thus provides a unique opportunity to study the pathogenesis of malaria in a single infection setting. An optimized protocol that permits efficient and reproducible vector transmission of P. c. chabaudi via Anopheles stephensi was developed. Results and conclusions This protocol was utilized for mosquito transmission of genetically distinct P. c. chabaudi isolates, highlighting differential parasite virulence within the mosquito vector and the spectrum of host susceptibility to infection initiated via the natural route, mosquito bite. An apposite experimental system in which to delineate the pathogenesis of malaria is described in detail.

  14. Variation in Aedes aegypti Mosquito Competence for Zika Virus Transmission.

    Roundy, Christopher M; Azar, Sasha R; Rossi, Shannan L; Huang, Jing H; Leal, Grace; Yun, Ruimei; Fernandez-Salas, Ildefonso; Vitek, Christopher J; Paploski, Igor A D; Kitron, Uriel; Ribeiro, Guilherme S; Hanley, Kathryn A; Weaver, Scott C; Vasilakis, Nikos

    2017-04-01

    To test whether Zika virus has adapted for more efficient transmission by Aedes aegypti mosquitoes, leading to recent urban outbreaks, we fed mosquitoes from Brazil, the Dominican Republic, and the United States artificial blood meals containing 1 of 3 Zika virus strains (Senegal, Cambodia, Mexico) and monitored infection, dissemination, and virus in saliva. Contrary to our hypothesis, Cambodia and Mexica strains were less infectious than the Senegal strain. Only mosquitoes from the Dominican Republic transmitted the Cambodia and Mexica strains. However, blood meals from viremic mice were more infectious than artificial blood meals of comparable doses; the Cambodia strain was not transmitted by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a murine blood meal (saliva titers up to 4 log 10 infectious units/collection). Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas.

  15. Outbreak of Zika Virus Infection, Chiapas State, Mexico, 2015, and First Confirmed Transmission by Aedes aegypti Mosquitoes in the Americas.

    Guerbois, Mathilde; Fernandez-Salas, Ildefonso; Azar, Sasha R; Danis-Lozano, Rogelio; Alpuche-Aranda, Celia M; Leal, Grace; Garcia-Malo, Iliana R; Diaz-Gonzalez, Esteban E; Casas-Martinez, Mauricio; Rossi, Shannan L; Del Río-Galván, Samanta L; Sanchez-Casas, Rosa M; Roundy, Christopher M; Wood, Thomas G; Widen, Steven G; Vasilakis, Nikos; Weaver, Scott C

    2016-11-01

     After decades of obscurity, Zika virus (ZIKV) has spread through the Americas since 2015 accompanied by congenital microcephaly and Guillain-Barré syndrome. Although these epidemics presumably involve transmission by Aedes aegypti, no direct evidence of vector involvement has been reported, prompting speculation that other mosquitoes such as Culex quinquefasciatus could be involved.  We detected an outbreak of ZIKV infection in southern Mexico in late 2015. Sera from suspected ZIKV-infected patients were analyzed for viral RNA and antibodies. Mosquitoes were collected in and around patient homes and tested for ZIKV.  Of 119 suspected ZIKV-infected patients, 25 (21%) were confirmed by RT-PCR of serum collected 1-8 days after the onset of signs and symptoms including rash, arthralgia, headache, pruritus, myalgia, and fever. Of 796 mosquitoes collected, A. aegypti yielded ZIKV detection by RT-PCR in 15 of 55 pools (27.3%). No ZIKV was detected in C. quinquefasciatus ZIKV sequences derived from sera and mosquitoes showed a monophyletic relationship suggestive of a point source introduction from Guatemala.  These results demonstrate the continued, rapid northward progression of ZIKV into North America with typically mild disease manifestations, and implicate A. aegypti for the first time as a principal vector in North America. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  16. The role of omega-3 long-chain polyunsaturated fatty acids in health and disease of the retina.

    SanGiovanni, John Paul; Chew, Emily Y

    2005-01-01

    In this work we advance the hypothesis that omega-3 (omega-3) long-chain polyunsaturated fatty acids (LCPUFAs) exhibit cytoprotective and cytotherapeutic actions contributing to a number of anti-angiogenic and neuroprotective mechanisms within the retina. omega-3 LCPUFAs may modulate metabolic processes and attenuate effects of environmental exposures that activate molecules implicated in pathogenesis of vasoproliferative and neurodegenerative retinal diseases. These processes and exposures include ischemia, chronic light exposure, oxidative stress, inflammation, cellular signaling mechanisms, and aging. A number of bioactive molecules within the retina affect, and are effected by such conditions. These molecules operate within complex systems and include compounds classified as eicosanoids, angiogenic factors, matrix metalloproteinases, reactive oxygen species, cyclic nucleotides, neurotransmitters and neuromodulators, pro-inflammatory and immunoregulatory cytokines, and inflammatory phospholipids. We discuss the relationship of LCPUFAs with these bioactivators and bioactive compounds in the context of three blinding retinal diseases of public health significance that exhibit both vascular and neural pathology. How is omega-3 LCPUFA status related to retinal structure and function? Docosahexaenoic acid (DHA), a major dietary omega-3 LCPUFA, is also a major structural lipid of retinal photoreceptor outer segment membranes. Biophysical and biochemical properties of DHA may affect photoreceptor membrane function by altering permeability, fluidity, thickness, and lipid phase properties. Tissue DHA status affects retinal cell signaling mechanisms involved in phototransduction. DHA may operate in signaling cascades to enhance activation of membrane-bound retinal proteins and may also be involved in rhodopsin regeneration. Tissue DHA insufficiency is associated with alterations in retinal function. Visual processing deficits have been ameliorated with DHA supplementation

  17. Rod photoreceptors express GPR55 in the adult vervet monkey retina

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

    2013-01-01

    . Yet, its formal classification is still a matter of debate. CB1R and CB2R expression patterns are well described for rodent and monkey retinas. In the monkey retina, CB1R has been localized in its neural (cone photoreceptor, horizontal, bipolar, amacrine and ganglion cells) and CB2R in glial...

  18. Real-time simulation of the retina allowing visualization of each processing stage

    Teeters, Jeffrey L.; Werblin, Frank S.

    1991-08-01

    The retina computes to let us see, but can we see the retina compute? Until now, the answer has been no, because the unconscious nature of the processing hides it from our view. Here the authors describe a method of seeing computations performed throughout the retina. This is achieved by using neurophysiological data to construct a model of the retina, and using a special-purpose image processing computer (PIPE) to implement the model in real time. Processing in the model is organized into stages corresponding to computations performed by each retinal cell type. The final stage is the transient (change detecting) ganglion cell. A CCD camera forms the input image, and the activity of a selected retinal cell type is the output which is displayed on a TV monitor. By changing the retina cell driving the monitor, the progressive transformations of the image by the retina can be observed. These simulations demonstrate the ubiquitous presence of temporal and spatial variations in the patterns of activity generated by the retina which are fed into the brain. The dynamical aspects make these patterns very different from those generated by the common DOG (Difference of Gaussian) model of receptive field. Because the retina is so successful in biological vision systems, the processing described here may be useful in machine vision.

  19. Pannexin1 in the outer retina of the zebrafish, Danio rerio

    Prochnow, N.; Hoffmann, S.; Vroman, R.; Klooster, J.; Bunse, S.; Kamermans, M.; Dermietzel, R.; Zoidl, G.

    2009-01-01

    In the retina, chemical and electrical synapses couple neurons into functional networks. New candidates encoding for electrical synapse proteins have recently emerged. In the present study, we determined the localization of the candidate protein pannexin1 (zfPanx1) in the zebrafish retina and

  20. Functional and Cellular Responses to Laser Injury in the Rat Snake Retina

    Glickman, Randolph D; Elliott, III, W. R; Kumar, Neeru

    2007-01-01

    .... This animal is of interest for vision research because its eye has an all-cone retina. A linear array of 5 thermal lesions was placed in the retina of anesthetized animals, near the area centralis, using a Nd:VO4 laser (532 nm...

  1. Preservation of Retina Ganglion Cell Function by Morphine in a Chronic Ocular-Hypertensive Rat Model

    Husain, Shahid; Abdul, Yasir; Crosson, Craig E.

    2012-01-01

    Morphine, a broad range opioid-receptors agonist, provides retina neuroprotection against glaucomatous injury in chronic experimental rat model. Morphine-induced retina neuroprotection in glaucoma model is mediated partly via inhibition of TNF-alpha production and caspase-3 and caspase-8 activation.

  2. Protein changes in the retina following experimental retinal detachment in rabbits

    Mandal, Nakul; Lewis, Geoffrey P.; Fisher, Steven K.

    2011-01-01

    Retinal detachment leads to the widespread cellular remodeling of the retina. The purpose of this study was to identify protein changes that accompany these cellular alterations by comparing the proteomic profiles of sham and experimentally detached rabbit retina. Elucidation of the proteins most...

  3. A comparison of some organizational characteristics of the mouse central retina and the human macula.

    Volland, Stefanie; Esteve-Rudd, Julian; Hoo, Juyea; Yee, Claudine; Williams, David S

    2015-01-01

    Mouse models have greatly assisted our understanding of retinal degenerations. However, the mouse retina does not have a macula, leading to the question of whether the mouse is a relevant model for macular degeneration. In the present study, a quantitative comparison between the organization of the central mouse retina and the human macula was made, focusing on some structural characteristics that have been suggested to be important in predisposing the macula to stresses leading to degeneration: photoreceptor density, phagocytic load on the RPE, and the relative thinness of Bruch's membrane. Light and electron microscopy measurements from retinas of two strains of mice, together with published data on human retinas, were used for calculations and subsequent comparisons. As in the human retina, the central region of the mouse retina possesses a higher photoreceptor cell density and a thinner Bruch's membrane than in the periphery; however, the magnitudes of these periphery to center gradients are larger in the human. Of potentially greater relevance is the actual photoreceptor cell density, which is much greater in the mouse central retina than in the human macula, underlying a higher phagocytic load for the mouse RPE. Moreover, at eccentricities that correspond to the peripheral half of the human macula, the rod to cone ratio is similar between mouse and human. Hence, with respect to photoreceptor density and phagocytic load of the RPE, the central mouse retina models at least the more peripheral part of the macula, where macular degeneration is often first evident.

  4. Novel acetylcholinesterase target site for malaria mosquito control.

    Yuan-Ping Pang

    2006-12-01

    Full Text Available Current anticholinesterase pesticides were developed during World War II and are toxic to mammals because they target a catalytic serine residue of acetylcholinesterases (AChEs in insects and in mammals. A sequence analysis of AChEs from 73 species and a three-dimensional model of a malaria-carrying mosquito (Anopheles gambiae AChE (AgAChE reported here show that C286 and R339 of AgAChE are conserved at the opening of the active site of AChEs in 17 invertebrate and four insect species, respectively. Both residues are absent in the active site of AChEs of human, monkey, dog, cat, cattle, rabbit, rat, and mouse. The 17 invertebrates include house mosquito, Japanese encephalitis mosquito, African malaria mosquito, German cockroach, Florida lancelet, rice leaf beetle, African bollworm, beet armyworm, codling moth, diamondback moth, domestic silkworm, honey bee, oat or wheat aphid, the greenbug, melon or cotton aphid, green peach aphid, and English grain aphid. The four insects are house mosquito, Japanese encephalitis mosquito, African malaria mosquito, and German cockroach. The discovery of the two invertebrate-specific residues enables the development of effective and safer pesticides that target the residues present only in mosquito AChEs rather than the ubiquitous serine residue, thus potentially offering an effective control of mosquito-borne malaria. Anti-AgAChE pesticides can be designed to interact with R339 and subsequently covalently bond to C286. Such pesticides would be toxic to mosquitoes but not to mammals.

  5. Visualization of house-entry behaviour of malaria mosquitoes.

    Spitzen, Jeroen; Koelewijn, Teun; Mukabana, W Richard; Takken, Willem

    2016-04-25

    Malaria mosquitoes often blood feed indoors on human hosts. The mosquitoes predominantly enter houses via open eaves. Host-seeking is odour-driven, and finding a host depends on the quality of the odour plume and whether the route towards the host is free of obstructions. Little is known about in-flight behaviour of mosquitoes during house entry. This semi-field study visualizes mosquito house entry in three dimensions (3D) and offers new insights for optimizing vector control interventions. The approach and house entry of Anopheles gambiae sensu stricto was studied in a semi-field set-up using video-recorded flight tracks and 3D analysis. Behavioural parameters of host-seeking female mosquitoes were visualized with respect to their position relative to the eave as well as whether a mosquito would enter or not. Host odour was standardized using an attractive synthetic blend in addition to CO2. The study was conducted in western Kenya at the Thomas Odhiambo Campus of the International Centre of Insect Physiology and Ecology, Mbita. The majority of host-seeking An. gambiae approached a house with a flight altitude at eave level, arriving within a horizontal arc of 180°. Fifty-five per cent of mosquitoes approaching a house did not enter or made multiple attempts before passing through the eave. During approach, mosquitoes greatly reduced their speed and the flight paths became more convoluted. As a result, mosquitoes that passed through the eave spent more than 80 % of the observed time within 30 cm of the eave. Mosquitoes that exited the eave departed at eave level and followed the edge of the roof (12.5 %) or quickly re-entered after exiting (9.6 %). The study shows that host-seeking mosquitoes, when entering a house, approach the eave in a wide angle to the house at eave level. Less than 25 % of approaching mosquitoes entered the house without interruption, whereas 12.5 % of mosquitoes that had entered left the house again within the time of observation

  6. Rhythmic ganglion cell activity in bleached and blind adult mouse retinas.

    Menzler, Jacob; Channappa, Lakshmi; Zeck, Guenther

    2014-01-01

    In retinitis pigmentosa--a degenerative disease which often leads to incurable blindness--the loss of photoreceptors deprives the retina from a continuous excitatory input, the so-called dark current. In rodent models of this disease this deprivation leads to oscillatory electrical activity in the remaining circuitry, which is reflected in the rhythmic spiking of retinal ganglion cells (RGCs). It remained unclear, however, if the rhythmic RGC activity is attributed to circuit alterations occurring during photoreceptor degeneration or if rhythmic activity is an intrinsic property of healthy retinal circuitry which is masked by the photoreceptor's dark current. Here we tested these hypotheses by inducing and analysing oscillatory activity in adult healthy (C57/Bl6) and blind mouse retinas (rd10 and rd1). Rhythmic RGC activity in healthy retinas was detected upon partial photoreceptor bleaching using an extracellular high-density multi-transistor-array. The mean fundamental spiking frequency in bleached retinas was 4.3 Hz; close to the RGC rhythm detected in blind rd10 mouse retinas (6.5 Hz). Crosscorrelation analysis of neighbouring wild-type and rd10 RGCs (separation distance rhythmic RGC spiking in these retinas is driven by a network of presynaptic neurons. The inhibition of glutamatergic ganglion cell input or the inhibition of gap junctional coupling abolished the rhythmic pattern. In rd10 and rd1 retinas the presynaptic network leads to local field potentials, whereas in bleached retinas additional pharmacological disinhibition is required to achieve detectable field potentials. Our results demonstrate that photoreceptor bleaching unmasks oscillatory activity in healthy retinas which shares many features with the functional phenotype detected in rd10 retinas. The quantitative physiological differences advance the understanding of the degeneration process and may guide future rescue strategies.

  7. Damage and functional recovery of the mouse retina after exposure to genotoxic agents

    Vinogradova, Yu.V.; Tronov, V.A.; Lyakhova, K.N.; Ostrovskij, M.A.

    2013-01-01

    As is known, the mature retina is characterized by high radiation resistance. We showed earlier that ionizing radiation at a dose of ≥25 Gy and the chemical genotoxic agent methylnitrosourea (MNU) in a concentration of ≥60 mg/kg induce acute retinal degeneration, combined with proapoptotic protein expression. The process has a high genotoxic threshold, below which no degeneration signs were traced. The aim of this work was to study the damaging effect of ionizing radiation and MNU on the functional activity of the retina and its ability to recover after exposure to these genotoxicants. The functional activity of the mouse retina was evaluated with electroretinograms (ERG). In parallel, morphological changes in the retina were controlled, and the TUNEL detection of the death of its cell elements was performed. It has been shown that gamma rays or accelerated proton irradiation below 15 Gy cause no structural or functional changes in the mouse retina, which confirms the mature retina's high radiation resistance. Irradiation with a higher dose of 25 Gy leads to photoreceptor layer destruction. This goes along with an increase in the number of the TUNEL-positive photoreceptors, among which are cells with fragmented nuclei, which are typical of apoptosis. MNU in a concentration of 70 mg/kg caused the irreversible loss of the retina's physiological activity, and the morphological degeneration of photoreceptors and their mass death. In a concentration of 35 mg/kg, however, MNU had no cytotoxic effect on the retina. Moreover, this dose caused a reversible ERG amplitude decrease. Also, adaptive response was observed in the retina, which became apparent after two consecutive MNU injections - first, at a dose of 17 mg/kg; then, at a cytotoxic dose of 70 mg/kg. These results point to the possibility of the neurohormesis effect, which was described concerning the retina's exposure to ionizing radiation and some chemicals.

  8. Expression of nitric oxide synthase during the development of RCS rat retinas.

    Sharma, R K; Warfvinge, K; Ehinger, B

    2001-01-01

    Nitric oxide (NO) has been reported to be both neurodestructive and neuroprotective in the central nervous system and could possibly play an important role in neurodegenerative disorders. On the assumption that NO synthesis may influence degenerative processes in the retina, we have examined the development and distribution of nitric-oxide-synthase(NOS)-immunoreactive cells in developing Royal College of Surgeons (RCS) rat retinas, which is an animal model for retinal degeneration. An antibody against constitutive neuronal NOS was used for immunocytochemistry on RCS rat retinas from postnatal (PN) days 3, 7, 10, 14, 35, 70 and 281 and compared with that in the normal rats of PN days 3, 7, 10, 14, 54 and adults. Immunoreactive cells were not seen in PN 3 retinas but were distinctly seen in the PN 7 retina along with a plexus in the inner plexiform layer. In both groups (normal and RCS rats) a distinct sublayering of the plexus in the inner plexiform layer could be seen at PN 10, which became more distinct at PN 14. The immunoreactive cells were detected also in the oldest retina examined, which was PN 281 in the case of RCS rats. In both groups, certain amacrine cells, certain bipolar cells and certain horizontal cells were found to be immunoreactive. In conclusion, the developmental timetable of the NOS immunoreactivity was identical in the normal and the RCS rat retinas. The NOS-immunoreactive cells persisted in the RCS retinas even when the retina had degenerated extensively. Abnormalities with the inducible isoforms of NOS cannot be ruled out from this study. We conclude that the chronological and qualitative development of the constitutive neuronal NOS immunoreactivity is normal in RCS rat retinas. Copyright 2001 S. Karger AG, Basel

  9. Wavefront optimized nonlinear microscopy of ex vivo human retinas

    Gualda, Emilio J.; Bueno, Juan M.; Artal, Pablo

    2010-03-01

    A multiphoton microscope incorporating a Hartmann-Shack (HS) wavefront sensor to control the ultrafast laser beam's wavefront aberrations has been developed. This instrument allowed us to investigate the impact of the laser beam aberrations on two-photon autofluorescence imaging of human retinal tissues. We demonstrated that nonlinear microscopy images are improved when laser beam aberrations are minimized by realigning the laser system cavity while wavefront controlling. Nonlinear signals from several human retinal anatomical features have been detected for the first time, without the need of fixation or staining procedures. Beyond the improved image quality, this approach reduces the required excitation power levels, minimizing the side effects of phototoxicity within the imaged sample. In particular, this may be important to study the physiology and function of the healthy and diseased retina.

  10. Resonant imaging of carotenoid pigments in the human retina

    Gellermann, Werner; Emakov, Igor V.; McClane, Robert W.

    2002-06-01

    We have generated high spatial resolution images showing the distribution of carotenoid macular pigments in the human retina using Raman spectroscopy. A low level of macular pigments is associated with an increased risk of developing age-related macular degeneration, a leading cause of irreversible blindness. Using excised human eyecups and resonant excitation of the pigment molecules with narrow bandwidth blue light from a mercury arc lamp, we record Raman images originating from the carbon-carbon double bond stretch vibrations of lutein and zeaxanthin, the carotenoids comprising human macular pigments. Our Raman images reveal significant differences among subjects, both in regard to absolute levels as well as spatial distribution within the macula. Since the light levels used to obtain these images are well below established safety limits, this technique holds promise for developing a rapid screening diagnostic in large populations at risk for vision loss from age-related macular degeneration.

  11. Simulated annealing in adaptive optics for imaging the eye retina

    Zommer, S.; Adler, J.; Lipson, S. G.; Ribak, E.

    2004-01-01

    Full Text:Adaptive optics is a method designed to correct deformed images in real time. Once the distorted wavefront is known, a deformable mirror is used to compensate the aberrations and return the wavefront to a plane wave. This study concentrates on methods that omit wave front sensing from the reconstruction process. Such methods use stochastic algorithms to find the extremum of a certain sharpness function, thereby correcting the image without any information on the wavefront. Theoretical work [l] has shown that the optical problem can be mapped onto a model for crystal roughening. The main algorithm applied is simulated annealing. We present a first hardware realization of this algorithm in an adaptive optics system designed to image the retina of the human eye

  12. Using Stem Cells to Model Diseases of the Outer Retina

    Camille Yvon

    2015-01-01

    Full Text Available Retinal degeneration arises from the loss of photoreceptors or retinal pigment epithelium (RPE. It is one of the leading causes of irreversible blindness worldwide with limited effective treatment options. Generation of induced pluripotent stem cell (IPSC-derived retinal cells and tissues from individuals with retinal degeneration is a rapidly evolving technology that holds a great potential for its use in disease modelling. IPSCs provide an ideal platform to investigate normal and pathological retinogenesis, but also deliver a valuable source of retinal cell types for drug screening and cell therapy. In this review, we will provide some examples of the ways in which IPSCs have been used to model diseases of the outer retina including retinitis pigmentosa (RP, Usher syndrome (USH, Leber congenital amaurosis (LCA, gyrate atrophy (GA, juvenile neuronal ceroid lipofuscinosis (NCL, Best vitelliform macular dystrophy (BVMD and age related macular degeneration (AMD.

  13. Using Stem Cells to Model Diseases of the Outer Retina.

    Yvon, Camille; Ramsden, Conor M; Lane, Amelia; Powner, Michael B; da Cruz, Lyndon; Coffey, Peter J; Carr, Amanda-Jayne F

    2015-01-01

    Retinal degeneration arises from the loss of photoreceptors or retinal pigment epithelium (RPE). It is one of the leading causes of irreversible blindness worldwide with limited effective treatment options. Generation of induced pluripotent stem cell (IPSC)-derived retinal cells and tissues from individuals with retinal degeneration is a rapidly evolving technology that holds a great potential for its use in disease modelling. IPSCs provide an ideal platform to investigate normal and pathological retinogenesis, but also deliver a valuable source of retinal cell types for drug screening and cell therapy. In this review, we will provide some examples of the ways in which IPSCs have been used to model diseases of the outer retina including retinitis pigmentosa (RP), Usher syndrome (USH), Leber congenital amaurosis (LCA), gyrate atrophy (GA), juvenile neuronal ceroid lipofuscinosis (NCL), Best vitelliform macular dystrophy (BVMD) and age related macular degeneration (AMD).

  14. Proteomic profiling of early degenerative retina of RCS rats.

    Zhu, Zhi-Hong; Fu, Yan; Weng, Chuan-Huang; Zhao, Cong-Jian; Yin, Zheng-Qin

    2017-01-01

    To identify the underlying cellular and molecular changes in retinitis pigmentosa (RP). Label-free quantification-based proteomics analysis, with its advantages of being more economic and consisting of simpler procedures, has been used with increasing frequency in modern biological research. Dystrophic RCS rats, the first laboratory animal model for the study of RP, possess a similar pathological course as human beings with the diseases. Thus, we employed a comparative proteomics analysis approach for in-depth proteome profiling of retinas from dystrophic RCS rats and non-dystrophic congenic controls through Linear Trap Quadrupole - orbitrap MS/MS, to identify the significant differentially expressed proteins (DEPs). Bioinformatics analyses, including Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation and upstream regulatory analysis, were then performed on these retina proteins. Finally, a Western blotting experiment was carried out to verify the difference in the abundance of transcript factor E2F1. In this study, we identified a total of 2375 protein groups from the retinal protein samples of RCS rats and non-dystrophic congenic controls. Four hundred thirty-four significantly DEPs were selected by Student's t -test. Based on the results of the bioinformatics analysis, we identified mitochondrial dysfunction and transcription factor E2F1 as the key initiation factors in early retinal degenerative process. We showed that the mitochondrial dysfunction and the transcription factor E2F1 substantially contribute to the disease etiology of RP. The results provide a new potential therapeutic approach for this retinal degenerative disease.

  15. Proteomic profiling of early degenerative retina of RCS rats

    Zhi-Hong Zhu

    2017-06-01

    Full Text Available AIM: To identify the underlying cellular and molecular changes in retinitis pigmentosa (RP. METHODS: Label-free quantification-based proteomics analysis, with its advantages of being more economic and consisting of simpler procedures, has been used with increasing frequency in modern biological research. Dystrophic RCS rats, the first laboratory animal model for the study of RP, possess a similar pathological course as human beings with the diseases. Thus, we employed a comparative proteomics analysis approach for in-depth proteome profiling of retinas from dystrophic RCS rats and non-dystrophic congenic controls through Linear Trap Quadrupole - orbitrap MS/MS, to identify the significant differentially expressed proteins (DEPs. Bioinformatics analyses, including Gene ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway annotation and upstream regulatory analysis, were then performed on these retina proteins. Finally, a Western blotting experiment was carried out to verify the difference in the abundance of transcript factor E2F1. RESULTS: In this study, we identified a total of 2375 protein groups from the retinal protein samples of RCS rats and non-dystrophic congenic controls. Four hundred thirty-four significantly DEPs were selected by Student’s t-test. Based on the results of the bioinformatics analysis, we identified mitochondrial dysfunction and transcription factor E2F1 as the key initiation factors in early retinal degenerative process. CONCLUSION: We showed that the mitochondrial dysfunction and the transcription factor E2F1 substantially contribute to the disease etiology of RP. The results provide a new potential therapeutic approach for this retinal degenerative disease.

  16. Photophysical properties of xanthophylls in carotenoproteins from human retinas.

    Billsten, Helena H; Bhosale, Prakash; Yemelyanov, Alexander; Bernstein, Paul S; Polívka, Tomás

    2003-08-01

    The macula of the human retina contains high amounts of the xanthophyll carotenoids lutein and zeaxanthin [a mixture of (3R,3'R)-zeaxanthin and (3R,3'S-meso)-zeaxanthin]. Recently, it was shown that the uptake and the stabilization of zeaxanthin and lutein into the retina are likely to be mediated by specific xanthophyll-binding proteins (XBP). Here, we have used femtosecond pump-probe spectroscopy to study the dynamics of the S1 state of these xanthophylls in xanthophyll-enriched and native XBP. The results from the native XBP and the enriched XBP were then compared with those for carotenoids in organic solvents and in detergent micelles. Steady-state and transient absorption spectra show that the incorporation of xanthophylls into the protein causes a redshift of the spectra, which is stronger for lutein than for zeaxanthin. The transient absorption spectra further indicate that a part of the xanthophylls remains unbound in the xanthophyll-enriched XBP. The transient absorption spectra of the native XBP prove the presence of both xanthophylls in native XBP. Although the S1 lifetime of lutein does not exhibit any changes when measured in solution, micelles or XBP, we have observed the influence of the environment on the S1 lifetime of meso-zeaxanthin, which has a longer (12 ps) lifetime in XBP than in solution (9 ps). The most pronounced effect was found for vibrational relaxation in the S1 state, which is significantly slower for xanthophylls in XBP compared with micelles and solution. This effect is more pronounced for meso-zeaxanthin, suggesting a specific site of binding of this carotenoid to XBP.

  17. Surveillance should be strengthened to improve epidemiological understandings of mosquito-borne Barmah Forest virus infection

    David Durrheim

    2012-08-01

    Full Text Available Introduction: Barmah Forest virus (BFV is a mosquito-borne virus causing epidemic polyarthritis in Australia. This study used case follow-up of cases from the surveillance system to demonstrate that routinely collected BFV notification data were an unreliable indicator of the true location of exposure.Methods: BFV notifications from June 2001 to May 2011 were extracted from the New South Wales (NSW Notifiable Conditions Information Management System to study case distribution. Disease cluster analysis was performed using spatial scan statistics. Exposure history data were collected from cases notified in 2010 and 2011 to accurately determine travel to high-risk areas.Results: Cluster analysis using address data identified an area of increased BFV disease incidence in the mid-north coast of NSW contiguous with estuarine wetlands. When travel to this area was investigated, 96.7% (29/30 cases reported having visited coastal regions within four weeks of developing symptoms.Discussion: Along the central NSW coastline, extensive wetlands occur in close proximity to populated areas. These wetlands provide ideal breeding habitats for a range of mosquito species implicated in the transmission of BFV. This is the first study to fully assess case exposure with findings suggesting that sporadic cases of BFV in people living further away from the coast do not reflect alternative exposure sites but are likely to result from travel to coastal regions. Spatial analysis by case address alone may lead to inaccurate understandings of the true distribution of arboviral diseases. Subsequently, this information has important implications for the collection of mosquito-borne disease surveillance information and public health response strategies.

  18. Modulation of Host Learning in Aedes aegypti Mosquitoes.

    Vinauger, Clément; Lahondère, Chloé; Wolff, Gabriella H; Locke, Lauren T; Liaw, Jessica E; Parrish, Jay Z; Akbari, Omar S; Dickinson, Michael H; Riffell, Jeffrey A

    2018-02-05

    How mosquitoes determine which individuals to bite has important epidemiological consequences. This choice is not random; most mosquitoes specialize in one or a few vertebrate host species, and some individuals in a host population are preferred over others. Mosquitoes will also blood feed from other hosts when their preferred is no longer abundant, but the mechanisms mediating these shifts between hosts, and preferences for certain individuals within a host species, remain unclear. Here, we show that olfactory learning may contribute to Aedes aegypti mosquito biting preferences and host shifts. Training and testing to scents of humans and other host species showed that mosquitoes can aversively learn the scent of specific humans and single odorants and learn to avoid the scent of rats (but not chickens). Using pharmacological interventions, RNAi, and CRISPR gene editing, we found that modification of the dopamine-1 receptor suppressed their learning abilities. We further show through combined electrophysiological and behavioral recordings from tethered flying mosquitoes that these odors evoke changes in both behavior and antennal lobe (AL) neuronal responses and that dopamine strongly modulates odor-evoked responses in AL neurons. Not only do these results provide direct experimental evidence that olfactory learning in mosquitoes can play an epidemiological role, but collectively, they also provide neuroanatomical and functional demonstration of the role of dopamine in mediating this learning-induced plasticity, for the first time in a disease vector insect. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Towards the genetic manipulation of mosquito disease vectors

    Crampton, J.M.; Lycett, G.J.; Warren, A.

    1998-01-01

    Our research is aimed at developing the technologies necessary to undertake the genetic manipulation of insect vector genomes. In the longer term, we wish to explore the potential that this technology may have for developing novel strategies for the control of vector-borne diseases. The focus of our current research has been to: i) identify and characterise endogenous transposable elements in the genomes of mosquito vectors -research has focussed on identifying both Class I and Class 11 elements and determining their structure and distribution within mosquito genomes; ii) develop and use transfection systems for mosquito cells in culture as a test bed for transformation vectors and promoters - transfection techniques, vector constructs and different promoters driving reporter genes have been utilised to optimise the transformation of both Aedes aegypti and Anopheles gambiae cells in culture; iii) identify putative promoter sequences which are induced in the female mosquito midgut when it takes a blood meal - the Anopheles gambiae trypsin gene locus has been cloned and sequenced and the intergenic regions assessed for their ability to induce reporter gene expression in mosquito gut cells. The progress we have made in each of these areas will be described and discussed in the context of our longer term aim which is to introduce genes coding for antiparasitic agents into mosquito genomes in such a way that they are expressed in the mosquito midgut and disrupt transmission of the malaria parasite. (author)

  20. Towards the genetic manipulation of mosquito disease vectors

    Crampton, J M; Lycett, G J; Warren, A [Division of Molecular Biology and Immunology, Liverpool School of Tropical Medicine, Liverpool (United Kingdom)

    1998-01-01

    Our research is aimed at developing the technologies necessary to undertake the genetic manipulation of insect vector genomes. In the longer term, we wish to explore the potential that this technology may have for developing novel strategies for the control of vector-borne diseases. The focus of our current research has been to: i) identify and characterise endogenous transposable elements in the genomes of mosquito vectors -research has focussed on identifying both Class I and Class 11 elements and determining their structure and distribution within mosquito genomes; ii) develop and use transfection systems for mosquito cells in culture as a test bed for transformation vectors and promoters - transfection techniques, vector constructs and different promoters driving reporter genes have been utilised to optimise the transformation of both Aedes aegypti and Anopheles gambiae cells in culture; iii) identify putative promoter sequences which are induced in the female mosquito midgut when it takes a blood meal - the Anopheles gambiae trypsin gene locus has been cloned and sequenced and the intergenic regions assessed for their ability to induce reporter gene expression in mosquito gut cells. The progress we have made in each of these areas will be described and discussed in the context of our longer term aim which is to introduce genes coding for antiparasitic agents into mosquito genomes in such a way that they are expressed in the mosquito midgut and disrupt transmission of the malaria parasite. (author). 41 refs, 2 figs.

  1. EPA-Registered Repellents for Mosquitoes Transmitting Emerging Viral Disease.

    Patel, Radha V; Shaeer, Kristy M; Patel, Pooja; Garmaza, Aleksey; Wiangkham, Kornwalee; Franks, Rachel B; Pane, Olivia; Carris, Nicholas W

    2016-12-01

    In many parts of the United States, mosquitoes were previously nuisance pests. However, they now represent a potential threat in the spread of viral diseases. The Aedes aegypti, Aedes albopictus, and Culex species mosquitoes are endemic to the United States and together may transmit a variety of viral diseases of growing concern, including West Nile virus, chikungunya, dengue fever, and Zika virus. The Centers for Disease Control and Prevention and the Environmental Protection Agency (EPA) recommend N,N-diethyl-meta-toluamide (DEET) as a first-line mosquito repellent, but for patients refusing to use DEET or other conventional repellents, guidance is limited to any EPA-registered product. Therefore, we conducted a systematic review of the literature to identify which EPA-registered personal mosquito repellent provides the best protection from A. aegypti, A. albopictus, and Culex spp. mosquitoes. We abstracted data from 62 published reports of EPA-registered mosquito repellents. The conventional repellent picaridin has the strongest data to support its use as a second-line agent, while IR3535 and oil of lemon eucalyptus are reasonably effective natural products. Citronella, catnip, and 2-undecanone offer limited protection or have limited data. These results can be used by pharmacists and other health care professionals to advise patients on the selection of an EPA-registered mosquito repellent. Regardless of the repellent chosen, it is vital for patients to follow all instructions/precautions in the product labeling to ensure safe and effective use. © 2016 Pharmacotherapy Publications, Inc.

  2. Biocontrol of larval mosquitoes by Acilius sulcatus (Coleoptera: Dytiscidae

    Banerjee Siddhartha S

    2008-10-01

    Full Text Available Abstract Background Problems associated with resistant mosquitoes and the effects on non-target species by chemicals, evoke a reason to find alternative methods to control mosquitoes, like the use of natural predators. In this regard, aquatic coleopterans have been explored less compared to other insect predators. In the present study, an evaluation of the role of the larvae of Acilius sulcatus Linnaeus 1758 (Coleoptera: Dytiscidae as predator of mosquito immatures was made in the laboratory. Its efficacy under field condition was also determined to emphasize its potential as bio-control agent of mosquitoes. Methods In the laboratory, the predation potential of the larvae of A. sulcatus was assessed using the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae as prey at varying predator and prey densities and available space. Under field conditions, the effectiveness of the larvae of A. sulcatus was evaluated through augmentative release in ten cemented tanks hosting immatures of different mosquito species at varying density. The dip density changes in the mosquito immatures were used as indicator for the effectiveness of A. sulcatus larvae. Results A single larva of A. sulcatus consumed on an average 34 IV instar larvae of Cx. quinquefasciatus in a 24 h period. It was observed that feeding rate of A. sulcatus did not differ between the light-on (6 a.m. – 6 p.m., and dark (6 p.m. – 6 a.m. phases, but decreased with the volume of water i.e., space availability. The prey consumption of the larvae of A. sulcatus differed significantly (P A. sulcatus larvae, while with the withdrawal, a significant increase (p A. sulcatus in regulating mosquito immatures. In the control tanks, mean larval density did not differ (p > 0.05 throughout the study period. Conclusion the larvae of the dytiscid beetle A. sulcatus proved to be an efficient predator of mosquito immatures and may be useful in biocontrol of medically important mosquitoes.

  3. UV light and urban pollution: bad cocktail for mosquitoes?

    Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane

    2014-01-01

    Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species-ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis-Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further

  4. Targeting the breeding sites of malaria mosquitoes: biological and physical control of malaria mosquito larvae

    Bukhari, S.T.

    2011-01-01

    Malaria causes an estimated 225 million cases and 781,000 deaths every year. About 85% of the deaths are in children under five years of age. Malaria is caused by the Plasmodium parasite which is transmitted by the Anopheles mosquito vector. Mainly two methods of intervention are used for vector control, i.e. insecticide-treated bed nets and indoor residual spraying. Both involve the use of insecticides and target Anopheles adults indoors. A rising increase in resistance against these insec...

  5. Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

    Sonja Hall-Mendelin

    2016-09-01

    Full Text Available Within the last 10 years Zika virus (ZIKV has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission.Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50 of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred.We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

  6. Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

    Hall-Mendelin, Sonja; Pyke, Alyssa T; Moore, Peter R; Mackay, Ian M; McMahon, Jamie L; Ritchie, Scott A; Taylor, Carmel T; Moore, Frederick A J; van den Hurk, Andrew F

    2016-09-01

    Within the last 10 years Zika virus (ZIKV) has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission. Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50) of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50)/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred. We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

  7. Quantitative Fundus Autofluorescence in Best Vitelliform Macular Dystrophy: RPE Lipofuscin is not Increased in Non-Lesion Areas of Retina.

    Sparrow, Janet R; Duncker, Tobias; Woods, Russell; Delori, François C

    2016-01-01

    Since the lipofuscin of retinal pigment epithelial (RPE) cells has been implicated in the pathogenesis of Best vitelliform macular dystrophy, we quantified fundus autofluorescence (quantitative fundus autofluorescence, qAF) as an indirect measure of RPE lipofuscin levels. Mean non-lesion qAF was found to be within normal limits for age. By spectral domain optical coherence tomography (SD-OCT) vitelliform lesions presented as fluid-filled subretinal detachments containing reflective material. We discuss photoreceptor outer segment debris as the source of the intense fluorescence of these lesions and loss of anion channel functioning as an explanation for the bullous photoreceptor-RPE detachment. Unexplained is the propensity of the disease for central retina.

  8. Nesting Bird “Host Funnel” Increases Mosquito-Bird Contact Rate

    CAILLOUËT, KEVIN A.; RIGGAN, ANNA E.; BULLUCK, LESLEY P.; CARLSON, JOHN C.; SABO, ROY T.

    2013-01-01

    Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from < 1 mosquito per trap night to 36.2 in the final 2 wk of the nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a “host f...

  9. Primary lymph node responses to mosquito bites.

    Mellink, J J; Vos, B J

    1977-03-29

    Post-auricular lymph node responses and changes in fresh weight of thymus and spleen of hamsters and mice at 4 and 8 days after primary exposure of both ears to 20 bites by the mosquito Aedes aegypti were studied quantitatively. In both hosts lymph node changes characteristic of the development of cell-mediated immune responses and those which are believed to lead to antibody production occurred, with the emphasis on the latter phenomena. No reactions of thymus and spleen were observed. The responses recorded are considered to be immunologically specific. In hamsters, but not in mice, the responses related to humoral sensitization coincided in time to a large extent with those of the cell-mediated immune processes. The stronger humoral responses in mice were probably in the first place the result of the relatively higher dosages applied.

  10. Clonal origins of cells in the pigmented retina of the zebrafish eye

    Streisinger, G.; Coale, F.; Taggart, C.; Walker, C.; Grunwald, D.J.

    1989-01-01

    Mosaic analysis has been used to study the clonal basis of the development of the pigmented retina of the zebrafish, Brachydanio rerio. Zebrafish embryos heterozygous for a recessive mutation at the gol-1 locus were exposed to gamma-irradiation at various developmental stages to create mosaic individuals consisting of wild-type pigmented cells and a clone of pigmentless (golden) cells in the eye. The contribution of individual embryonic cells to the pigmented retina was measured and the total number of cells in the embryo that contributed descendants to this tissue was determined. Until the 32-cell stage, almost every blastomere has some descendants that participate in the formation of the pigmented retina of the zebrafish. During subsequent cell divisions, up to the several thousand-cell stage, the number of ancestral cells is constant: approximately 40 cells are present that will give rise to progeny in the pigmented retina. Analysis of the size of clones in the pigmented retina indicates that the cells of this tissue do not arise through a rigid series of cell divisions originating in the early embryo. The findings that each cleavage stage cell contributes to the pigmented retina and yet the contribution of such cells is highly variable are consistent with the interpretation that clonal descendants of different blastomeres normally intermix extensively prior to formation of the pigmented retina

  11. Microglia in the mouse retina alter the structure and function of retinal pigmented epithelial cells: a potential cellular interaction relevant to AMD.

    Wenxin Ma

    2009-11-01

    Full Text Available Age-related macular degeneration (AMD is a leading cause of legal blindness in the elderly in the industrialized word. While the immune system in the retina is likely to be important in AMD pathogenesis, the cell biology underlying the disease is incompletely understood. Clinical and basic science studies have implicated alterations in the retinal pigment epithelium (RPE layer as a locus of early change. Also, retinal microglia, the resident immune cells of the retina, have been observed to translocate from their normal position in the inner retina to accumulate in the subretinal space close to the RPE layer in AMD eyes and in animal models of AMD.In this study, we examined the effects of retinal microglia on RPE cells using 1 an in vitro model where activated retinal microglia are co-cultured with primary RPE cells, and 2 an in vivo mouse model where retinal microglia are transplanted into the subretinal space. We found that retinal microglia induced in RPE cells 1 changes in RPE structure and distribution, 2 increased expression and secretion of pro-inflammatory, chemotactic, and pro-angiogenic molecules, and 3 increased extent of in vivo choroidal neovascularization in the subretinal space.These findings share similarities with important pathological features found in AMD and suggest the relevance of microglia-RPE interactions in AMD pathogenesis. We speculate that the migration of retinal microglia into the subretinal space in early stages of the disease induces significant changes in RPE cells that perpetuate further microglial accumulation, increase inflammation in the outer retina, and fosters an environment conducive for the formation of neovascular changes responsible for much of vision loss in advanced AMD.

  12. Distribution of tubulin, kinesin, and dynein in light- and dark-adapted octopus retinas.

    Martinez, J M; Elfarissi, H; De Velasco, B; Ochoa, G H; Miller, A M; Clark, Y M; Matsumoto, B; Robles, L J

    2000-01-01

    Cephalopod retinas exhibit several responses to light and dark adaptation, including rhabdom size changes, photopigment movements, and pigment granule migration. Light- and dark-directed rearrangements of microfilament and microtubule cytoskeletal transport pathways could drive these changes. Recently, we localized actin-binding proteins in light-/dark-adapted octopus rhabdoms and suggested that actin cytoskeletal rearrangements bring about the formation and degradation of rhabdomere microvilli subsets. To determine if the microtubule cytoskeleton and associated motor proteins control the other light/dark changes, we used immunoblotting and immunocytochemical procedures to map the distribution of tubulin, kinesin, and dynein in dorsal and ventral halves of light- and dark-adapted octopus retinas. Immunoblots detected alpha- and beta-tubulin, dynein intermediate chain, and kinesin heavy chain in extracts of whole retinas. Epifluorescence and confocal microscopy showed that the tubulin proteins were distributed throughout the retina with more immunoreactivity in retinas exposed to light. Kinesin localization was heavy in the pigment layer of light- and dark-adapted ventral retinas but was less prominent in the dorsal region. Dynein distribution also varied in dorsal and ventral retinas with more immunoreactivity in light- and dark-adapted ventral retinas and confocal microscopy emphasized the granular nature of this labeling. We suggest that light may regulate the distribution of microtubule cytoskeletal proteins in the octopus retina and that position, dorsal versus ventral, also influences the distribution of motor proteins. The microtubule cytoskeleton is most likely involved in pigment granule migration in the light and dark and with the movement of transport vesicles from the photoreceptor inner segments to the rhabdoms.

  13. Biological Control Strategies for Mosquito Vectors of Arboviruses.

    Huang, Yan-Jang S; Higgs, Stephen; Vanlandingham, Dana L

    2017-02-10

    Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.

  14. Biological Control Strategies for Mosquito Vectors of Arboviruses

    Yan-Jang S. Huang

    2017-02-01

    Full Text Available Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.

  15. Applications of natural products in the control of mosquito ...

    Applications of natural products in the control of mosquito-transmitted ... African Journal of Biotechnology ... Ultimately, a paradigm shift in research that evaluates natural products in a comparative manner will help to produce new materials for ...

  16. 12 Statistical Survey of Mosquito Vectors.cdr

    Administrator

    Introduction. Environmental factors are of prime importance to ... Mexico, Asia, Europe, Russia, Greenland,. Canada, United ... of the countries where the incidence of mosquito borne ... where all laundry washing work is being carried out from ...

  17. Polymer nanoparticles containing essential oils: new options for mosquito control.

    Werdin González, Jorge Omar; Jesser, Emiliano Nicolás; Yeguerman, Cristhian Alan; Ferrero, Adriana Alicia; Fernández Band, Beatriz

    2017-07-01

    Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, two different essential oils (EO) (geranium, Geranium maculatum, and bergamot, Citrus bergamia) loaded polymeric nanoparticle (PN) were elaborated using polyethylene glycol (PEG) and chitosan (Qx) as the polymeric matrix/coating. In addition, the mosquito larvicidal acute and residual activity of the PN was evaluated on Culex pipiens pipiens. The physicochemical characterization of PN revealed that PEG-PN had sizes nanoparticles containing essential oil are a promising source of eco-friendly mosquito larvicidal products.

  18. Original Research Risk factors for Anopheles mosquitoes in rural ...

    have suggested that the strongest risk factor for malaria. Original ..... mosquitoes are adapted to urban environments characterised .... Reduction of childhood malaria by social marketing of insecticide-treated ... and ICF Macro; 2011. 22.

  19. Ecological effects on arbovirus-mosquito cycles of transmission.

    Tabachnick, Walter J

    2016-12-01

    Mosquitoes transmit many viruses to a variety of hosts. Cycles of mosquito borne arbovirus transmission are the result of complex interactions between the mosquito, the arbovirus and the host that are influenced by genetic variations in a variety of traits in each that are all influenced by many environmental factors. R 0 , the basic reproduction number or mean number of individuals infected from a single infected individual, is a measure of mosquito borne arbovirus transmission. Understanding the causes for the distribution of R 0 in any transmission cycle is a daunting challenge due to the lack of information on the genetic and environmental variances that influence R 0 . Information about the major factors influencing R 0 for specific transmission cycles is essential to develop efficient and effective strategies to reduce transmission in different cycles and locations. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. 1 Scepticism towards insecticide treated mosquito nets for malaria ...

    Abstract: Despite existence of effective tools for malaria control, malaria ... breaks from traditional approach that tend to study low uptake of health ... Key words: scepticism, low uptake, mosquito nets, malaria, social marketing, Tanzania.

  1. Dirofilaria repens microfilariae in Aedes vexans mosquitoes in Slovakia

    Bocková, E.; Rudolf, Ivo; Kočišová, A.; Betášová, Lenka; Venclíková, Kristýna; Mendel, Jan; Hubálek, Zdeněk

    2013-01-01

    Roč. 112, č. 10 (2013), s. 3465-3470 ISSN 0932-0113 Institutional support: RVO:68081766 Keywords : Dirofilaria * mosquitoes * Aedes vexans Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.327, year: 2013

  2. Scepticism towards insecticide treated mosquito nets for malaria ...

    Scepticism towards insecticide treated mosquito nets for malaria control in rural ... especially among under-five year children and pregnant women in poor rural ... through social marketing strategy for malaria control prior to the introduction of ...

  3. Applications of natural products in the control of mosquito ...

    STORAGESEVER

    2009-12-29

    Dec 29, 2009 ... part of disease prevention strategies, many regions of the world are still struggling .... Although new syn- thetic chemicals have not yet impacted the market, there are a number of chemicals available to target mosquito larvae ...

  4. Biological Control of Mosquito Vectors: Past, Present, and Future

    Giovanni Benelli

    2016-10-01

    Full Text Available Mosquitoes represent the major arthropod vectors of human disease worldwide transmitting malaria, lymphatic filariasis, and arboviruses such as dengue virus and Zika virus. Unfortunately, no treatment (in the form of vaccines or drugs is available for most of these diseases andvectorcontrolisstillthemainformofprevention. Thelimitationsoftraditionalinsecticide-based strategies, particularly the development of insecticide resistance, have resulted in significant efforts to develop alternative eco-friendly methods. Biocontrol strategies aim to be sustainable and target a range of different mosquito species to reduce the current reliance on insecticide-based mosquito control. In thisreview, weoutline non-insecticide basedstrategiesthat havebeenimplemented orare currently being tested. We also highlight the use of mosquito behavioural knowledge that can be exploited for control strategies.

  5. Simple intervention to reduce mosquito breeding in waste stabilisation ponds

    Ensink, Jeroen H J; Mukhtar, Muhammad; van der Hoek, Wim

    2007-01-01

    Waste stabilisation ponds (WSP) are the preferred method for treatment of urban wastewater in low-income countries but, especially in arid regions, the pond systems can be important breeding sites for mosquitoes of medical importance. In a WSP system in Faisalabad, Pakistan, we assessed the impact...... of simple environmental interventions on mosquito occurrence and abundance. Reducing the amount of floating matter in the ponds, eliminating emergent vegetation and repairing cracks in the cement structure reduced the number of mosquito-positive samples in the intervention ponds to almost zero, whereas...... the control ponds had a significant number of positive samples. This suggests that a combination of simple low-cost interventions is a feasible environmental management strategy for vector control in WSP systems that are located in areas where medically important mosquitoes may breed in the shallow ponds....

  6. Mosquito management in the face of natural selection

    Agusto, Folashade B.; Bewick, Sharon A.; Parshad, Rana

    2012-01-01

    The sterile insect technique (SIT) is an appealing method for managing mosquito populations while avoiding the environmental and social costs associated with more traditional control strategies like insecticide application. Success of SIT, however

  7. The organization of melanopsin-immunoreactive cells in microbat retina.

    Jeong, Mi-Jin; Kim, Hang-Gu; Jeon, Chang-Jin

    2018-01-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) respond to light and play roles in non-image forming vision, such as circadian rhythms, pupil responses, and sleep regulation, or image forming vision, such as processing visual information and directing eye movements in response to visual clues. The purpose of the present study was to identify the distribution, types, and proportion of melanopsin-immunoreactive (IR) cells in the retina of a nocturnal animal, i.e., the microbat (Rhinolophus ferrumequinum). Three types of melanopsin-IR cells were observed in the present study. The M1 type had dendritic arbors that extended into the OFF sublayer of the inner plexiform layer (IPL). M1 soma locations were identified either in the ganglion cell layer (GCL, M1c; 21.00%) or in the inner nuclear layer (INL, M1d; 5.15%). The M2 type had monostratified dendrites in the ON sublayer of the IPL and their cell bodies lay in the GCL (M2; 5.79%). The M3 type was bistratified cells with dendrites in both the ON and OFF sublayers of the IPL. M3 soma locations were either in the GCL (M3c; 26.66%) or INL (M3d; 4.69%). Additionally, some M3c cells had curved dendrites leading up towards the OFF sublayer of the IPL and down to the ON sublayer of the IPL (M3c-crv; 7.67%). Melanopsin-IR cells displayed a medium soma size and medium dendritic field diameters. There were 2-5 primary dendrites and sparsely branched dendrites with varicosities. The total number of the neurons in the GCL was 12,254.17 ± 660.39 and that of the optic nerve axons was 5,179.04 ± 208.00 in the R. ferrumequinum retina. The total number of melanopsin-IR cells was 819.74 ± 52.03. The ipRGCs constituted approximately 15.83% of the total RGC population. This study demonstrated that the nocturnal microbat, R. ferrumequinum, has a much higher density of melanopsin-IR cells than documented in diurnal animals.

  8. The organization of melanopsin-immunoreactive cells in microbat retina.

    Mi-Jin Jeong

    Full Text Available Intrinsically photosensitive retinal ganglion cells (ipRGCs respond to light and play roles in non-image forming vision, such as circadian rhythms, pupil responses, and sleep regulation, or image forming vision, such as processing visual information and directing eye movements in response to visual clues. The purpose of the present study was to identify the distribution, types, and proportion of melanopsin-immunoreactive (IR cells in the retina of a nocturnal animal, i.e., the microbat (Rhinolophus ferrumequinum. Three types of melanopsin-IR cells were observed in the present study. The M1 type had dendritic arbors that extended into the OFF sublayer of the inner plexiform layer (IPL. M1 soma locations were identified either in the ganglion cell layer (GCL, M1c; 21.00% or in the inner nuclear layer (INL, M1d; 5.15%. The M2 type had monostratified dendrites in the ON sublayer of the IPL and their cell bodies lay in the GCL (M2; 5.79%. The M3 type was bistratified cells with dendrites in both the ON and OFF sublayers of the IPL. M3 soma locations were either in the GCL (M3c; 26.66% or INL (M3d; 4.69%. Additionally, some M3c cells had curved dendrites leading up towards the OFF sublayer of the IPL and down to the ON sublayer of the IPL (M3c-crv; 7.67%. Melanopsin-IR cells displayed a medium soma size and medium dendritic field diameters. There were 2-5 primary dendrites and sparsely branched dendrites with varicosities. The total number of the neurons in the GCL was 12,254.17 ± 660.39 and that of the optic nerve axons was 5,179.04 ± 208.00 in the R. ferrumequinum retina. The total number of melanopsin-IR cells was 819.74 ± 52.03. The ipRGCs constituted approximately 15.83% of the total RGC population. This study demonstrated that the nocturnal microbat, R. ferrumequinum, has a much higher density of melanopsin-IR cells than documented in diurnal animals.

  9. Assessing the impacts of truck based ultra-low volume applications of mosquito adulticides on honey bees (Apis mellifera)

    Mosquito control reduces populations of mosquitoes to minimize the risk of mosquito-borne diseases. As part of an integrated approach to mosquito control, application of adulticides can be effective in rapidly reducing mosquito populations during times of high arbovirus transmission. However, impact...

  10. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    Gendrin, MEM; Christophides; Linenberg, Inbar

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii . We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clar...

  11. Non-Genetic Determinants of Mosquito Competence for Malaria Parasites

    Lef?vre, Thierry; Vantaux, Am?lie; Dabir?, Kounbobr R.; Mouline, Karine; Cohuet, Anna

    2013-01-01

    Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies reve...

  12. Pesticides and public health: integrated methods of mosquito management.

    Rose, R. I.

    2001-01-01

    Pesticides have a role in public health as part of sustainable integrated mosquito management. Other components of such management include surveillance, source reduction or prevention, biological control, repellents, traps, and pesticide-resistance management. We assess the future use of mosquito control pesticides in view of niche markets, incentives for new product development, Environmental Protection Agency registration, the Food Quality Protection Act, and improved pest management strate...

  13. Repellency of Lantana camara (Verbenaceae) flowers against Aedes mosquitoes.

    Dua, V K; Gupta, N C; Pandey, A C; Sharma, V P

    1996-09-01

    The repellent effect of Lantana camara flowers was evaluated against Aedes mosquitoes. Lantana flower extract in coconut oil provided 94.5% protection from Aedes albopictus and Ae. aegypti. The mean protection time was 1.9 h. One application of Lantana flower can provide more than 50% protection up to 4 h against the possible bites of Aedes mosquitoes. No adverse effects of the human volunteers were observed through 3 months after the application.

  14. Factors influencing stakeholders attitudes toward genetically modified aedes mosquito.

    Amin, Latifah; Hashim, Hasrizul

    2015-06-01

    Dengue fever is a debilitating and infectious disease that could be life-threatening. It is caused by the dengue virus which affects millions of people in the tropical area. Currently, there is no cure for the disease as there is no vaccine available. Thus, prevention of the vector population using conventional methods is by far the main strategy but has been found ineffective. A genetically modified (GM) mosquito is among the favoured alternatives to curb dengue fever in Malaysia. Past studies have shown that development and diffusion of gene technology products depends heavily upon public acceptance. The purpose of this study is to identify the relevant factors influencing stakeholders' attitudes toward the GM Aedes mosquito and to analyse the relationships between all the factors using the structural equation model. A survey was carried out on 509 respondents from various stakeholder groups in the Klang Valley region of Malaysia. Results of the survey have confirmed that public perception towards complex issues such as gene technology should be seen as a multi-faceted process. The perceived benefit-perceived risk balance is very important in determining the most predominant predictor of attitudes toward a GM mosquito. In this study the stakeholders perceived the benefit of the GM mosquito as outweighing its risk, translating perceived benefit as the most important direct predictor of attitudes toward the GM mosquito. Trust in key players has a direct influence on attitudes toward the GM mosquito while moral concern exhibited an indirect influence through perceived benefits. Other factors such as attitudes toward technology and nature were also indirect predictors of attitudes toward the GM mosquito while religiosity and engagement did not exhibited any significant roles. The research findings serve as a useful database to understand public acceptance and the social construct of public attitudes towards the GM mosquito to combat dengue.

  15. Malpighian Tubules as Novel Targets for Mosquito Control

    Peter M. Piermarini

    2017-01-01

    Full Text Available The Malpighian tubules and hindgut are the renal excretory tissues of mosquitoes; they are essential to maintaining hemolymph water and solute homeostasis. Moreover, they make important contributions to detoxifying metabolic wastes and xenobiotics in the hemolymph. We have focused on elucidating the molecular mechanisms of Malpighian tubule function in adult female mosquitoes and developing chemical tools as prototypes for next-generation mosquitocides that would act via a novel mechanism of action (i.e., renal failure. To date, we have targeted inward rectifier potassium (Kir channels expressed in the Malpighian tubules of the yellow fever mosquito Aedes aegypti and malaria mosquito Anopheles gambiae. Inhibition of these channels with small molecules inhibits transepithelial K+ and fluid secretion in Malpighian tubules, leading to a disruption of hemolymph K+ and fluid homeostasis in adult female mosquitoes. In addition, we have used next-generation sequencing to characterize the transcriptome of Malpighian tubules in the Asian tiger mosquito Aedes albopictus, before and after blood meals, to reveal new molecular targets for potentially disrupting Malpighian tubule function. Within 24 h after a blood meal, the Malpighian tubules enhance the mRNA expression of genes encoding mechanisms involved with the detoxification of metabolic wastes produced during blood digestion (e.g., heme, NH3, reactive oxygen species. The development of chemical tools targeting these molecular mechanisms in Malpighian tubules may offer a promising avenue for the development of mosquitocides that are highly-selective against hematophagous females, which are the only life stage that transmits pathogens.

  16. Blood-feeding ecology of mosquitoes in zoos.

    Tuten, H C; Bridges, W C; Paul, K S; Adler, P H

    2012-12-01

    To determine if the unique host assemblages in zoos influence blood-feeding by mosquitoes (Diptera: Culicidae), a sampling programme was conducted in Greenville and Riverbanks Zoos, South Carolina, U.S.A., from April 2009 to October 2010. A total of 4355 female mosquitoes of 14 species were collected, of which 106 individuals of nine species were blood-fed. The most common taxa were Aedes albopictus (Skuse), Aedes triseriatus (Say), Anopheles punctipennis (Say), Culex erraticus (Dyar & Knab), Culex pipiens complex (L.) and Culex restuans (Theobald). Molecular analyses (cytochrome b) of bloodmeals revealed that mosquitoes fed on captive animals, humans and wildlife, and took mixed bloodmeals. Host species included one amphibian, 16 birds, 10 mammals (including humans) and two reptiles. Minimum dispersal distances after feeding on captive hosts ranged from 15.5 m to 327.0 m. Mosquito-host associations generally conformed to previous accounts, indicating that mosquito behaviour inside zoos reflects that outside zoos. However, novel variation in host use, including new, exotic host records, warrants further investigation. Zoos, thus, can be used as experiment environments in which to study mosquito behaviour, and the findings extrapolated to non-zoo areas, while providing medical and veterinary benefits to zoo animals, employees and patrons. © 2012 The Authors. Medical and Veterinary Entomology © 2012 The Royal Entomological Society.

  17. Mosquitoes rely on their gut microbiota for development

    Coon, Kerri L.; Vogel, Kevin J.; Brown, Mark R.; Strand, Michael R.

    2014-01-01

    Field studies indicate adult mosquitoes (Culicidae) host low diversity communities of bacteria that vary greatly among individuals and species. In contrast, it remains unclear how adult mosquitoes acquire their microbiome, what influences community structure, and whether the microbiome is important for survival. Here we used pyrosequencing of 16S rRNA to characterize the bacterial communities of three mosquito species reared under identical conditions. Two of these species, Aedes aegypti and Anopheles gambiae, are anautogenous and must blood feed to produce eggs, while one, Georgecraigius atropalpus, is autogenous and produces eggs without blood feeding. Each mosquito species contained a low diversity community comprised primarily of aerobic bacteria acquired primarily from the aquatic habitat in which larvae developed. Our results suggested the communities in Ae. aegypti and An. gambiae larvae share more similarities with one another than with Ge. atropalpus. Studies with Ae. aegypti also strongly suggested that adults transstadially acquired several members of the larval bacterial community, but only four genera of bacteria present in blood fed females were detected on eggs. Functional assays showed that axenic larvae of each species failed to develop beyond the first instar. Experiments with Ae. aegypti indicated several members of the microbial community and Escherichia coli successfully colonized axenic larvae and rescued development. Overall, our results provide new insights about the acquisition and structure of bacterial communities in mosquitoes. They also indicate three mosquito species spanning the breadth of the Culicidae depend on their gut microbiome for development. PMID:24766707

  18. Nesting bird "host funnel" increases mosquito-bird contact rate.

    Caillouët, Kevin A; Riggan, Anna E; Bulluck, Lesley P; Carlson, John C; Sabo, Roy T

    2013-03-01

    Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a "host funnel," concentrating host-seeking mosquitoes to the few remaining nestlings. The relative abundance of mosquitoes collected by the NMT suggests that significantly more Aedes albopictus (Skuse) and Culex pipiens (L.) /restuans (Theobald) sought nesting bird bloodmeals than were predicted by their relative abundances in CO2-baited Centers for Disease Control and Prevention light and gravid traps. Culex salinarius (Coquillett) and Culex erraticus Dyar and Knab were collected in NMTs in proportion to their relative abundances in the generic traps. Temporal host funnels and nesting bird host specificity may enhance arbovirus amplification and explain observed West Nile virus and St. Louis encephalitis virus amplification periods.

  19. GLOBE Observer Mosquito Habitat Mapper: Geoscience and Public Health Connections

    Low, R.; Boger, R. A.

    2017-12-01

    The global health crisis posed by vector-borne diseases is so great in scope that it is clearly insurmountable without the active help of tens-or hundreds- of thousands of individuals, working to identify and eradicate risk in communities around the world. Mobile devices equipped with data collection capabilities and visualization opportunities are lowering the barrier for participation in data collection efforts. The GLOBE Observer Mosquito Habitat Mapper (MHM) provides citizen scientists with an easy to use mobile platform to identify and locate mosquito breeding sites in their community. The app also supports the identification of vector taxa in the larvae development phase via a built-in key, which provides important information for scientists and public health officials tracking the rate of range expansion of invasive vector species and associated health threats. GO Mosquito is actively working with other citizen scientist programs across the world to ensure interoperability of data through standardization of metadata fields specific to vector monitoring, and through the development of APIs that allow for data exchange and shared data display through a UN-sponsored proof of concept project, Global Mosquito Alert. Avenues of application for mosquito vector data-both directly, by public health entities, and by modelers who employ remotely sensed environmental data to project mosquito population dynamics and epidemic disease will be featured.

  20. Disrupting Mosquito Reproduction and Parasite Development for Malaria Control.

    Lauren M Childs

    2016-12-01

    Full Text Available The control of mosquito populations with insecticide treated bed nets and indoor residual sprays remains the cornerstone of malaria reduction and elimination programs. In light of widespread insecticide resistance in mosquitoes, however, alternative strategies for reducing transmission by the mosquito vector are urgently needed, including the identification of safe compounds that affect vectorial capacity via mechanisms that differ from fast-acting insecticides. Here, we show that compounds targeting steroid hormone signaling disrupt multiple biological processes that are key to the ability of mosquitoes to transmit malaria. When an agonist of the steroid hormone 20-hydroxyecdysone (20E is applied to Anopheles gambiae females, which are the dominant malaria mosquito vector in Sub Saharan Africa, it substantially shortens lifespan, prevents insemination and egg production, and significantly blocks Plasmodium falciparum development, three components that are crucial to malaria transmission. Modeling the impact of these effects on Anopheles population dynamics and Plasmodium transmission predicts that disrupting steroid hormone signaling using 20E agonists would affect malaria transmission to a similar extent as insecticides. Manipulating 20E pathways therefore provides a powerful new approach to tackle malaria transmission by the mosquito vector, particularly in areas affected by the spread of insecticide resistance.

  1. Composition of human skin microbiota affects attractiveness to malaria mosquitoes.

    Niels O Verhulst

    Full Text Available The African malaria mosquito Anopheles gambiae sensu stricto continues to play an important role in malaria transmission, which is aggravated by its high degree of anthropophily, making it among the foremost vectors of this disease. In the current study we set out to unravel the strong association between this mosquito species and human beings, as it is determined by odorant cues derived from the human skin. Microbial communities on the skin play key roles in the production of human body odour. We demonstrate that the composition of the skin microbiota affects the degree of attractiveness of human beings to this mosquito species. Bacterial plate counts and 16S rRNA sequencing revealed that individuals that are highly attractive to An. gambiae s.s. have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive. Bacterial genera that are correlated with the relative degree of attractiveness to mosquitoes were identified. The discovery of the connection between skin microbial populations and attractiveness to mosquitoes may lead to the development of new mosquito attractants and personalized methods for protection against vectors of malaria and other infectious diseases.

  2. Mosquito larval source management for controlling malaria

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2015-01-01

    Background Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). Objectives To evaluate the effectiveness of mosquito LSM for preventing malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. Selection criteria We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. Data collection and analysis At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software

  3. Impacts of the creation, expansion and management of English wetlands on mosquito presence and abundance - developing strategies for future disease mitigation.

    Medlock, Jolyon M; Vaux, Alexander G C

    2015-03-03

    The incidence of mosquito-borne diseases is increasing in Europe, partly due to the incursion of a number of invasive species known to be vectors of dengue and chikungunya viruses, but also due to the involvement of native species in the transmission of West Nile virus and malaria. For some of these pathogens, there is a risk of the re-emergence of vector-borne diseases that were once widespread in Europe, but declined partly due to large-scale land-drainage projects. Some mosquito species exploit container habitats as breeding sites in urban areas; an adaptation to human-made micro-habitats resulting from increased urbanisation. However, many species thrive in natural wetland ecosystems. Owing to the impacts of climate change there is an urgent need for environmental adaptation, such as the creation of new wetlands to mitigate coastal and inland flooding. In some cases, these initiatives can be coupled with environmental change strategies to protect a range of endangered flora and fauna species by enhancing and extending wetland landscapes, which may by driven by European legislation, particularly in urban areas. This paper reviews field studies conducted in England to assess the impact of newly created wetlands on mosquito colonisation in a) coastal, b) urban and c) arable reversion habitats. It also considers the impact of wetland management on mosquito populations and explores the implications of various water and vegetation management options on the range of British mosquito species. Understanding the impact of wetland creation and management strategies on mosquito prevalence and the potential risk of increasing the levels of nuisance or disease vector species will be crucial in informing health and well-being risk assessments, guiding targeted control, and anticipating the social effects of extreme weather and climate change. Although new wetlands will certainly extend aquatic habitats for mosquitoes, not all species will become a major nuisance or a vector

  4. Islet-1 Immunoreactivity in the Developing Retina of Xenopus laevis

    Guadalupe Álvarez-Hernán

    2013-01-01

    Full Text Available The LIM-homeodomain transcription factor Islet1 (Isl1 has been widely used as a marker of neuronal differentiation in the developing visual system of different classes of vertebrates, including mammals, birds, reptiles, and fish. In the present study, we analyzed the spatial and temporal distribution of Isl1-immunoreactive cells during Xenopus laevis retinal development and its relation to the formation of the retinal layers, and in combination with different markers of cell differentiation. The earliest Isl1 expression appeared at St29-30 in the cell nuclei of sparse differentiating neuroblasts located in the vitreal surface of the undifferentiated retina. At St35-36, abundant Isl1-positive cells accumulated at the vitreal surface of the neuroepithelium. As development proceeded and through the postmetamorphic juveniles, Isl1 expression was identified in subpopulations of ganglion cells and in subsets of amacrine, bipolar, and horizontal cells. These data together suggest a possible role for Isl1 in the early differentiation and maintenance of different retinal cell types, and Isl1 can serve as a specific molecular marker for the study of retinal cell specification in X. laevis.

  5. Development of neural retina in retinopathy of prematurity

    Yi Luo

    2015-10-01

    Full Text Available Retinopathy of prematurity(ROPis an important cause of infant blindness and visual impairment in the world, of which main clinical characteristics are peripheral retinal vascular abnormalities, including large non-perfusion area and abnormal neovascularization. Numerous researches have demonstrated that ROP affects the differentiation and maturity of retinal photoreceptor cells, with more significantly effect on rods than cones, and later mostly caused ametropia, strabismus, amblyopia and a series of abnormal visual functions, the specific mechanism remains unclear. After treatments, even the retinal vascular proliferation lesions disappear itself, but the abnormal development of photoreceptor cells and the resulting visual dysfunction will persist. Currently the best evaluation mean of clinical assessment about retinal function is mainly visual electrophysiology, especially flash electroretinogram(f-ERG, which can reflect the whole retinal functional status before ganglion cells, has a unique significance for the evaluation of retinal photoreceptor cells function. In this review, we aims at the development of neural retina(mainly photoreceptor cellsand its related mechanisms, also the visual function changes appeared in the late period about ROP and its mechanisms, guiding us to pursuit better methods for treatment.

  6. Mouse embryonic retina delivers information controlling cortical neurogenesis.

    Ciro Bonetti

    2010-12-01

    Full Text Available The relative contribution of extrinsic and intrinsic mechanisms to cortical development is an intensely debated issue and an outstanding question in neurobiology. Currently, the emerging view is that interplay between intrinsic genetic mechanisms and extrinsic information shape different stages of cortical development. Yet, whereas the intrinsic program of early neocortical developmental events has been at least in part decoded, the exact nature and impact of extrinsic signaling are still elusive and controversial. We found that in the mouse developing visual system, acute pharmacological inhibition of spontaneous retinal activity (retinal waves-RWs during embryonic stages increase the rate of corticogenesis (cell cycle withdrawal. Furthermore, early perturbation of retinal spontaneous activity leads to changes of cortical layer structure at a later time point. These data suggest that mouse embryonic retina delivers long-distance information capable of modulating cell genesis in the developing visual cortex and that spontaneous activity is the candidate long-distance acting extrinsic cue mediating this process. In addition, these data may support spontaneous activity to be a general signal coordinating neurogenesis in other developing sensory pathways or areas of the central nervous system.

  7. Cholesterol in the retina: the best is yet to come

    Pikuleva, Irina A.; Curcio, Christine A.

    2014-01-01

    Historically understudied, cholesterol in the retina is receiving more attention now because of genetic studies showing that several cholesterol-related genes are risk factors for age-related macular degeneration (AMD) and because eye pathology studies showing high cholesterol content of drusen, aging Bruch's membrane, and newly found subretinal lesions. The challenge before us is determining how the cholesterol-AMD link is realized. Meeting this challenge will require an excellent understanding these genes’ roles in retinal physiology and how chorioretinal cholesterol is maintained. In the first half of this review, we will succinctly summarize physico-chemical properties of cholesterol, its distribution in the human body, general principles of maintenance and metabolism, and differences in cholesterol handling in human and mouse that impact on experimental approaches. This information will provide a backdrop to the second part of the review focusing on unique aspects of chorioretinal cholesterol homeostasis, aging in Bruch's membrane, cholesterol in AMD lesions, a model for lesion biogenesis, a model for macular vulnerability based on vascular biology, and alignment of AMD-related genes and pathobiology using cholesterol and an atherosclerosis-like progression as unifying features. We conclude with recommendations for the most important research steps we can take towards delineating the cholesterol-AMD link. PMID:24704580

  8. The Analysis of Artificial Retina Organization for Signal Processing

    WEIHui

    2004-01-01

    Machine vision is an active branch of artificial intelligence. An important problem in this area is the trade-off among efficiency, accuracy and computation complexity. The human visual system can keep watchfulness to the perimeter of a viewing field while at the same time focus on the center of the field for fine information processing. This mechanism of appropriate assignment of computing resources can reduce the demand for huge and complex hardware structure. Therefore, the design of a computer model based on the biological visual mechanism is an effective approach to resolve problems in machine vision. In this paper, a multi-layer neural model is developed based on the features of receptive field of ganglion in retina to simulate multi-scale perceptive fields of ganglion cell. The neural model can maintain alert on the outer area of the image while capturing and processing more important information in the central part. It may provide valuable inspiration for the implementation of real-time processing and avoidance of huge computation in machine vision.

  9. Lattice degeneration of the retina and retinal detachment.

    Semes, L P

    1992-01-01

    Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.

  10. Frequency spectrum might act as communication code between retina and visual cortex I

    Xu Yang

    2015-12-01

    Full Text Available AIM: To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1. METHODS: Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG and pattern visually evoked potential (PVEP and fast Fourier transform has been used to analyze the frequency components of those signals. RESULTS: The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. CONCLUSION: The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

  11. Müller glia provide essential tensile strength to the developing retina

    MacDonald, Ryan B.; Randlett, Owen; Oswald, Julia; Yoshimatsu, Takeshi

    2015-01-01

    To investigate the cellular basis of tissue integrity in a vertebrate central nervous system (CNS) tissue, we eliminated Müller glial cells (MG) from the zebrafish retina. For well over a century, glial cells have been ascribed a mechanical role in the support of neural tissues, yet this idea has not been specifically tested in vivo. We report here that retinas devoid of MG rip apart, a defect known as retinoschisis. Using atomic force microscopy, we show that retinas without MG have decreased resistance to tensile stress and are softer than controls. Laser ablation of MG processes showed that these cells are under tension in the tissue. Thus, we propose that MG act like springs that hold the neural retina together, finally confirming an active mechanical role of glial cells in the CNS. PMID:26416961

  12. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas - a comparative study

    Christiansen, Anders Tolstrup; Kiilgaard, Jens Folke; Klemp, Kristian

    2018-01-01

    retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY......Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including...... humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy...

  13. Maturação funcional da retina em bebês prematuros

    Adriana Berezovsky

    2007-06-01

    Full Text Available A retina humana ainda não está totalmente desenvolvida no nascimento. Só após o nascimento é que ocorrem mudanças anatômicas como o aumento na densidade de cones centrais e o alongamento do segmento externo dos fotorreceptores. As mudanças funcionais que ocorrem na retina com a maturação no primeiro ano de vida podem ser avaliadas pela técnica do eletrorretinograma de campo total, que representa a atividade somada da retina distal em resposta à luz. Abordaremos aspectos da maturação funcional da retina avaliada pelo eletrorretinograma em bebês prematuros.

  14. Frequency spectrum might act as communication code between retina and visual cortex I.

    Yang, Xu; Gong, Bo; Lu, Jian-Wei

    2015-01-01

    To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1). Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG) and pattern visually evoked potential (PVEP) and fast Fourier transform has been used to analyze the frequency components of those signals. The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

  15. Illumination-invariant face recognition with a contrast sensitive silicon retina

    Buhmann, J.M. [Rheinische Friedrich-Wilhelms-Univ., Bonn (Germany). Inst. fuer Informatik II; Lades, M. [Bochum Univ. (Germany). Inst. fuer Neuroinformatik; Eeckman, F. [Lawrence Livermore National Lab., CA (United States)

    1993-11-29

    Changes in lighting conditions strongly effect the performance and reliability of computer vision systems. We report face recognition results under drastically changing lighting conditions for a computer vision system which concurrently uses a contrast sensitive silicon retina and a conventional, gain controlled CCD camera. For both input devices the face recognition system employs an elastic matching algorithm with wavelet based features to classify unknown faces. To assess the effect of analog on-chip preprocessing by the silicon retina the CCD images have been digitally preprocessed with a bandpass filter to adjust the power spectrum. The silicon retina with its ability to adjust sensitivity increases the recognition rate up to 50 percent. These comparative experiments demonstrate that preprocessing with an analog VLSI silicon retina generates image data enriched with object-constant features.

  16. Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

    ROBERTO PAES-DE-CARVALHO

    2002-09-01

    Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

  17. Myopathy associated with pigmentary degeneration of the retina and high protein content of cerebrospinal fluid Miopatia associada a degeneração pigmentar da retina e hiperproteinorraquia

    José Antonio Levy

    1974-06-01

    Full Text Available The cases of two brothers suffering from a myopathy associated with pigmentary degeneration of the retina and increase of protein content of the cerebrospinal fluid are reported.Foram estudados dois pacientes, filhos de pais não consanguíneos, com quadro miopático, iniciado na segunda década da vida, com predomínio na musculatura das cinturas e da face. Em ambos os casos havia degeneração pigmentar da retina e aumento da taxa protéica no líquido cefalorraqueano.

  18. Distribution of [35S] taurine in mouse retina after intravitreal and intravascular injection

    Pourcho, R.G.

    1977-01-01

    The distribution of [ 35 S] taurine in mouse retinae was studied by autoradiographic techniques after either intravitreal or intravascular injection. The route of injection did not affect the final localization. The major sites of label accumulation were the outer nuclear layer, the inner nuclear layer, and Mueller cell processes adjacent to the vitreal surface. The distribution was consistent with the interpretation that taurine was localized within two cellular compartments of mouse retina, photoreceptor cells and Mueller cells. (author)

  19. Eilat virus displays a narrow mosquito vector range.

    Nasar, Farooq; Haddow, Andrew D; Tesh, Robert B; Weaver, Scott C

    2014-12-17

    Most alphaviruses are arthropod-borne and utilize mosquitoes as vectors for transmission to susceptible vertebrate hosts. This ability to infect both mosquitoes and vertebrates is essential for maintenance of most alphaviruses in nature. A recently characterized alphavirus, Eilat virus (EILV), isolated from a pool of Anopheles coustani s.I. is unable to replicate in vertebrate cell lines. The EILV host range restriction occurs at both attachment/entry as well as genomic RNA replication levels. Here we investigated the mosquito vector range of EILV in species encompassing three genera that are responsible for maintenance of other alphaviruses in nature. Susceptibility studies were performed in four mosquito species: Aedes albopictus, A. aegypti, Anopheles gambiae, and Culex quinquefasciatus via intrathoracic and oral routes utilizing EILV and EILV expressing red fluorescent protein (-eRFP) clones. EILV-eRFP was injected at 10(7) PFU/mL to visualize replication in various mosquito organs at 7 days post-infection. Mosquitoes were also injected with EILV at 10(4)-10(1) PFU/mosquito and virus replication was measured via plaque assays at day 7 post-infection. Lastly, mosquitoes were provided bloodmeals containing EILV-eRFP at doses of 10(9), 10(7), 10(5) PFU/mL, and infection and dissemination rates were determined at 14 days post-infection. All four species were susceptible via the intrathoracic route; however, replication was 10-100 fold less than typical for most alphaviruses, and infection was limited to midgut-associated muscle tissue and salivary glands. A. albopictus was refractory to oral infection, while A. gambiae and C. quinquefasciatus were susceptible only at 10(9) PFU/mL dose. In contrast, A. aegypti was susceptible at both 10(9) and 10(7) PFU/mL doses, with body infection rates of 78% and 63%, and dissemination rates of 26% and 8%, respectively. The exclusion of vertebrates in its maintenance cycle may have facilitated the adaptation of EILV to a single

  20. A review of mixed malaria species infections in anopheline mosquitoes

    Day Nicholas PJ

    2011-08-01

    Full Text Available Abstract Background In patients with malaria mixed species infections are common and under reported. In PCR studies conducted in Asia mixed infection rates often exceed 20%. In South-East Asia, approximately one third of patients treated for falciparum malaria experience a subsequent Plasmodium vivax infection with a time interval suggesting relapse. It is uncertain whether the two infections are acquired simultaneously or separately. To determine whether mixed species infections in humans are derived from mainly from simultaneous or separate mosquito inoculations the literature on malaria species infection in wild captured anopheline mosquitoes was reviewed. Methods The biomedical literature was searched for studies of malaria infection and species identification in trapped wild mosquitoes and artificially infected mosquitoes. The study location and year, collection methods, mosquito species, number of specimens, parasite stage examined (oocysts or sporozoites, and the methods of parasite detection and speciation were tabulated. The entomological results in South East Asia were compared with mixed infection rates documented in patients in clinical studies. Results In total 63 studies were identified. Individual anopheline mosquitoes were examined for different malaria species in 28 of these. There were 14 studies from Africa; four with species evaluations in individual captured mosquitoes (SEICM. One study, from Ghana, identified a single mixed infection. No mixed infections were identified in Central and South America (seven studies, two SEICM. 42 studies were conducted in Asia and Oceania (11 from Thailand; 27 SEICM. The proportion of anophelines infected with Plasmodium falciparum parasites only was 0.51% (95% CI: 0.44 to 0.57%, for P. vivax only was 0.26% (95% CI: 0.21 to 0.30%, and for mixed P. falciparum and P. vivax infections was 0.036% (95% CI: 0.016 to 0.056%. The proportion of mixed infections in mosquitoes was significantly higher

  1. Localization and Developmental Expression Patterns of CSPG in the RCS Rat Retina

    Li-Feng Chen

    2011-05-01

    Full Text Available Purpose: Investigate changes in chondroitin sulfate proteoglycan (CSPG distribution in Royal College of Surgeons (RCS rat retinae. Could CSPGs distribution act as a physical barrier to transplanted cell migration in degenerating retinae? Methods: CSPG expression was examined in RCS and Long-Evans rat retinae from birth to postnatal day 150 (PND150 using immunofluorescence and western-blots. Results: Both groups showed a rapid rise in CSPG expression on PND14, which peaked on PND21 before declining to lower levels by PND35. CSPG expression had risen again by PND90 and remained elevated for the duration of the study (PND150. However, from PND21, CSPG expression was significantly higher (p ≤ 0.05, n = 5 in Long-Evans rat retinae. CSPG-positive cells were localized in the ganglion cell layer (GCL and the photoreceptor outer segment debris zone (DZ; CSPG expression in the DZ was the main contributor to the higher expression in older animals for both groups. Conclusions: Increased expression of CSPGs in the DZ may act as a physical barrier following retinal cellular transplantation. CSPGs in the GCL is probably related to dendritic changes. CSPG accumulation in the older retinae suggests that aging influences the microenvironment in the retina, which may affect the efficacy of cell transplantation.

  2. Optic nerve signals in a neuromorphic chip I: Outer and inner retina models.

    Zaghloul, Kareem A; Boahen, Kwabena

    2004-04-01

    We present a novel model for the mammalian retina and analyze its behavior. Our outer retina model performs bandpass spatiotemporal filtering. It is comprised of two reciprocally connected resistive grids that model the cone and horizontal cell syncytia. We show analytically that its sensitivity is proportional to the space-constant-ratio of the two grids while its half-max response is set by the local average intensity. Thus, this outer retina model realizes luminance adaptation. Our inner retina model performs high-pass temporal filtering. It features slow negative feedback whose strength is modulated by a locally computed measure of temporal contrast, modeling two kinds of amacrine cells, one narrow-field, the other wide-field. We show analytically that, when the input is spectrally pure, the corner-frequency tracks the input frequency. But when the input is broadband, the corner frequency is proportional to contrast. Thus, this inner retina model realizes temporal frequency adaptation as well as contrast gain control. We present CMOS circuit designs for our retina model in this paper as well. Experimental measurements from the fabricated chip, and validation of our analytical results, are presented in the companion paper [Zaghloul and Boahen (2004)].

  3. Adaptation of the Central Retina for High Acuity Vision: Cones, the Fovea and the Avascular Zone

    Provis, Jan M; Dubis, Adam M; Maddess, Ted; Carroll, Joseph

    2013-01-01

    Presence of a fovea centralis is directly linked to molecular specification of an avascular area in central retina, before the fovea (or `pit') begins to form. Modeling suggests that mechanical forces, generated within the eye, initiate formation of a pit within the avascular area, and its later remodeling in the postnatal period. Within the avascular area the retina is dominated by `midget' circuitry, in which signals are transferred from a single cone to a single bipolar cell, then a single ganglion cell. Thus in inner, central retina there are relatively few lateral connections between neurons. This renders the region adaptable to tangential forces, that translocate of ganglion cells laterally / centrifugally, to form the fovea. Optical coherence tomography enables live imaging of the retina, and shows that there is greater variation in the morphology of foveae in humans than previously thought. This variation is associated with differences in size of the avascular area and appears to be genetically based, but can be modified by environmental factors, including prematurity. Even when the fovea is absent (foveal hypoplasia), cones in central retina adopt an elongated and narrow morphology, enabling them to pack more densely to increase the sampling rate, and to act as more effective waveguides. Given these findings, what then is the adaptive advantage of a fovea? We suggest that the advantages of having a pit in central retina are relatively few, and minor, but together work to enhance acuity. PMID:23500068

  4. Defects in the outer limiting membrane are associated with rosette development in the Nrl-/- retina.

    Michael W Stuck

    Full Text Available The neural retinal leucine zipper (Nrl knockout mouse is a widely used model to study cone photoreceptor development, physiology, and molecular biology in the absence of rods. In the Nrl(-/- retina, rods are converted into functional cone-like cells. The Nrl(-/- retina is characterized by large undulations of the outer nuclear layer (ONL commonly known as rosettes. Here we explore the mechanism of rosette development in the Nrl(-/- retina. We report that rosettes first appear at postnatal day (P8, and that the structure of nascent rosettes is morphologically distinct from what is seen in the adult retina. The lumen of these nascent rosettes contains a population of aberrant cells protruding into the subretinal space that induce infolding of the ONL. Morphologically adult rosettes do not contain any cell bodies and are first detected at P15. The cells found in nascent rosettes are photoreceptors in origin but lack inner and outer segments. We show that the adherens junctions between photoreceptors and Müller glia which comprise the retinal outer limiting membrane (OLM are not uniformly formed in the Nrl(-/- retina and thus allow protrusion of a population of developing photoreceptors into the subretinal space where their maturation becomes delayed. These data suggest that the rosettes of the Nrl(-/- retina arise due to defects in the OLM and delayed maturation of a subset of photoreceptors, and that rods may play an important role in the proper formation of the OLM.

  5. Dispersal of Engineered Male Aedes aegypti Mosquitoes.

    Winskill, Peter; Carvalho, Danilo O; Capurro, Margareth L; Alphey, Luke; Donnelly, Christl A; McKemey, Andrew R

    2015-11-01

    Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m). Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

  6. Determinants of Arbovirus Vertical Transmission in Mosquitoes.

    Sebastian Lequime

    2016-05-01

    Full Text Available Vertical transmission (VT and horizontal transmission (HT of pathogens refer to parental and non-parental chains of host-to-host transmission. Combining HT with VT enlarges considerably the range of ecological conditions in which a pathogen can persist, but the factors governing the relative frequency of each transmission mode are poorly understood for pathogens with mixed-mode transmission. Elucidating these factors is particularly important for understanding the epidemiology of arthropod-borne viruses (arboviruses of public health significance. Arboviruses are primarily maintained by HT between arthropod vectors and vertebrate hosts in nature, but are occasionally transmitted vertically in the vector population from an infected female to her offspring, which is a proposed maintenance mechanism during adverse conditions for HT. Here, we review over a century of published primary literature on natural and experimental VT, which we previously assembled into large databases, to identify biological factors associated with the efficiency of arbovirus VT in mosquito vectors. Using a robust statistical framework, we highlight a suite of environmental, taxonomic, and physiological predictors of arbovirus VT. These novel insights contribute to refine our understanding of strategies employed by arboviruses to persist in the environment and cause substantial public health concern. They also provide hypotheses on the biological processes underlying the relative VT frequency for pathogens with mixed-mode transmission that can be tested empirically.

  7. Zika virus emergence in mosquitoes in southeastern Senegal, 2011.

    Diawo Diallo

    Full Text Available Zika virus (ZIKV; genus Flavivirus, family Flaviviridae is maintained in a zoonotic cycle between arboreal Aedes spp. mosquitoes and nonhuman primates in African and Asian forests. Spillover into humans has been documented in both regions and the virus is currently responsible for a large outbreak in French Polynesia. ZIKV amplifications are frequent in southeastern Senegal but little is known about their seasonal and spatial dynamics. The aim of this paper is to describe the spatio-temporal patterns of the 2011 ZIKV amplification in southeastern Senegal.Mosquitoes were collected monthly from April to December 2011 except during July. Each evening from 18:00 to 21:00 hrs landing collections were performed by teams of 3 persons working simultaneously in forest (canopy and ground, savannah, agriculture, village (indoor and outdoor and barren land cover sites. Mosquitoes were tested for virus infection by virus isolation and RT-PCR. ZIKV was detected in 31 of the 1,700 mosquito pools (11,247 mosquitoes tested: Ae. furcifer (5, Ae. luteocephalus (5, Ae. africanus (5, Ae. vittatus (3, Ae. taylori, Ae. dalzieli, Ae. hirsutus and Ae. metallicus (2 each and Ae. aegypti, Ae. unilinaetus, Ma. uniformis, Cx. perfuscus and An. coustani (1 pool each collected in June (3, September (10, October (11, November (6 and December (1. ZIKV was detected from mosquitoes collected in all land cover classes except indoor locations within villages. The virus was detected in only one of the ten villages investigated.This ZIKV amplification was widespread in the Kédougou area, involved several mosquito species as probable vectors, and encompassed all investigated land cover classes except indoor locations within villages. Aedes furcifer males and Aedes vittatus were found infected within a village, thus these species are probably involved in the transmission of Zika virus to humans in this environment.

  8. A spatial model of mosquito host-seeking behavior.

    Bree Cummins

    Full Text Available Mosquito host-seeking behavior and heterogeneity in host distribution are important factors in predicting the transmission dynamics of mosquito-borne infections such as dengue fever, malaria, chikungunya, and West Nile virus. We develop and analyze a new mathematical model to describe the effect of spatial heterogeneity on the contact rate between mosquito vectors and hosts. The model includes odor plumes generated by spatially distributed hosts, wind velocity, and mosquito behavior based on both the prevailing wind and the odor plume. On a spatial scale of meters and a time scale of minutes, we compare the effectiveness of different plume-finding and plume-tracking strategies that mosquitoes could use to locate a host. The results show that two different models of chemotaxis are capable of producing comparable results given appropriate parameter choices and that host finding is optimized by a strategy of flying across the wind until the odor plume is intercepted. We also assess the impact of changing the level of host aggregation on mosquito host-finding success near the end of the host-seeking flight. When clusters of hosts are more tightly associated on smaller patches, the odor plume is narrower and the biting rate per host is decreased. For two host groups of unequal number but equal spatial density, the biting rate per host is lower in the group with more individuals, indicative of an attack abatement effect of host aggregation. We discuss how this approach could assist parameter choices in compartmental models that do not explicitly model the spatial arrangement of individuals and how the model could address larger spatial scales and other probability models for mosquito behavior, such as Lévy distributions.

  9. Analyzing mosquito (Diptera: culicidae diversity in Pakistan by DNA barcoding.

    Muhammad Ashfaq

    Full Text Available Although they are important disease vectors mosquito biodiversity in Pakistan is poorly known. Recent epidemics of dengue fever have revealed the need for more detailed understanding of the diversity and distributions of mosquito species in this region. DNA barcoding improves the accuracy of mosquito inventories because morphological differences between many species are subtle, leading to misidentifications.Sequence variation in the barcode region of the mitochondrial COI gene was used to identify mosquito species, reveal genetic diversity, and map the distribution of the dengue-vector species in Pakistan. Analysis of 1684 mosquitoes from 491 sites in Punjab and Khyber Pakhtunkhwa during 2010-2013 revealed 32 species with the assemblage dominated by Culex quinquefasciatus (61% of the collection. The genus Aedes (Stegomyia comprised 15% of the specimens, and was represented by six taxa with the two dengue vector species, Ae. albopictus and Ae. aegypti, dominant and broadly distributed. Anopheles made up another 6% of the catch with An. subpictus dominating. Barcode sequence divergence in conspecific specimens ranged from 0-2.4%, while congeneric species showed from 2.3-17.8% divergence. A global haplotype analysis of disease-vectors showed the presence of multiple haplotypes, although a single haplotype of each dengue-vector species was dominant in most countries. Geographic distribution of Ae. aegypti and Ae. albopictus showed the later species was dominant and found in both rural and urban environments.As the first DNA-based analysis of mosquitoes in Pakistan, this study has begun the construction of a barcode reference library for the mosquitoes of this region. Levels of genetic diversity varied among species. Because of its capacity to differentiate species, even those with subtle morphological differences, DNA barcoding aids accurate tracking of vector populations.

  10. Characteristic lesions in mouse retina irradiated with accelerated iron particles

    Malachowski, M.J.; Philpott, D.E.; Corbett, R.L.; Tobias, C.A.

    1981-01-01

    A program is underway to determine the radiation hazards of HZE particles using the Bevalac, a heavy-ion accelerator at LBL. Our earlier work with helium, carbon, neon, and argon particles, and exposure to rats to HZE particles in space flight demonstrated some deleterious biological effects. TEM studies have shown that some visual cells were missing and dislocated; these were termed channel lesions. Recently obtained is evidence that a single iron HZE particle may affect a series of cells. Mice were irradiated with 0.1, 0.3, 1, 10, or 25 rad of 590 MeV/amu initial kinetic energy iron particles in groups of 10 animals per dose point. Irradiated and control animals were sacrificed at intervals from one week to two years postirradiation. The eye samples were dehydrated, critical points dried with freon, fractured, and Au-Pd coated for SEM, or plastic embedded, sectioned, and stained for TEM. Additionally, dry fractured samples viewed with the SEM were embedded in plastic, sectioned, and stained for the TEM. Characteristic tunnel shaped lesions were observed with the SEM. Stereo pairs showed tunnels of various lengths up to 100 μm. Light microscopy of serially cut sections from the same material had vacuoles (V) extending the same length. TEM of the same specimen and specimens prepared only for TEM exhibited large vacuoles, greater than or equal to 2 μm, in the inner segment (IS) and outer segment (OS) layers. Severe membrane disruption was found bordering the vacuoles and gross nuclear degeneration (ND) and loose tissue (LT) were seen in the outer nuclear layer (ONL). The number of lesions increased with increasing dose. Microscopy of the control retina failed to demonstrate similar lesions

  11. Endoscopic device for functional imaging of the retina

    Barriga, Simon; Lohani, Sweyta; Martell, Bret; Soliz, Peter; Ts'o, Dan

    2011-03-01

    Non-invasive imaging of retinal function based on the recording of spatially distributed reflectance changes evoked by visual stimuli has to-date been performed primarily using modified commercial fundus cameras. We have constructed a prototype retinal functional imager, using a commercial endoscope (Storz) for the frontend optics, and a low-cost back-end that includes the needed dichroic beam splitter to separate the stimulus path from the imaging path. This device has been tested to demonstrate its performance for the delivery of adequate near infrared (NIR) illumination, intensity of the visual stimulus and reflectance return in the imaging path. The current device was found to be capable of imaging reflectance changes of 0.1%, similar to that observable using the modified commercial fundus camera approach. The visual stimulus (a 505nm spot of 0.5secs) was used with an interrogation illumination of 780nm, and a sequence of imaged captured. At each pixel, the imaged signal was subtracted and normalized by the baseline reflectance, so that the measurement was ΔR/R. The typical retinal activity signal observed had a ΔR/R of 0.3-1.0%. The noise levels were measured when no stimulus was applied and found to vary between +/- 0.05%. Functional imaging has been suggested as a means to provide objective information on retina function that may be a preclinical indicator of ocular diseases, such as age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy. The endoscopic approach promises to yield a significantly more economical retinal functional imaging device that would be clinically important.

  12. Hemocyte-mediated phagocytosis and melanization in the mosquito Armigeres subalbatus following immune challenge by bacteria.

    Hillyer, Julián F; Schmidt, Shelley L; Christensen, Bruce M

    2003-07-01

    Mosquitoes are important vectors of disease. These insects respond to invading organisms with strong cellular and humoral immune responses that share many similarities with vertebrate immune systems. The strength and specificity of these responses are directly correlated to a mosquito's ability to transmit disease. In the current study, we characterized the hemocytes (blood cells) of Armigeres subalbatus by morphology (ultrastructure), lectin binding, enzyme activity, immunocytochemistry, and function. We found four hemocyte types: granulocytes, oenocytoids, adipohemocytes, and thrombocytoids. Granulocytes contained acid phosphatase activity and bound the exogenous lectins Helix pomatia agglutinin, Galanthus nivalis lectin, and wheat germ agglutinin. Following bacteria inoculation, granulocytes mounted a strong phagocytic response as early as 5 min postexposure. Bacteria also elicited a hemocyte-mediated melanization response. Phenoloxidase, the rate-limiting enzyme in the melanization pathway, was present exclusively in oenocytoids and in many of the melanotic capsules enveloping bacteria. The immune responses mounted against different bacteria were not identical; gram(-) Escherichia coli were predominantly phagocytosed and gram(+) Micrococcus luteus were melanized. These studies implicate hemocytes as the primary line of defense against bacteria.

  13. Vision-Based Perception and Classification of Mosquitoes Using Support Vector Machine

    Masataka Fuchida

    2017-01-01

    Full Text Available The need for a novel automated mosquito perception and classification method is becoming increasingly essential in recent years, with steeply increasing number of mosquito-borne diseases and associated casualties. There exist remote sensing and GIS-based methods for mapping potential mosquito inhabitants and locations that are prone to mosquito-borne diseases, but these methods generally do not account for species-wise identification of mosquitoes in closed-perimeter regions. Traditional methods for mosquito classification involve highly manual processes requiring tedious sample collection and supervised laboratory analysis. In this research work, we present the design and experimental validation of an automated vision-based mosquito classification module that can deploy in closed-perimeter mosquito inhabitants. The module is capable of identifying mosquitoes from other bugs such as bees and flies by extracting the morphological features, followed by support vector machine-based classification. In addition, this paper presents the results of three variants of support vector machine classifier in the context of mosquito classification problem. This vision-based approach to the mosquito classification problem presents an efficient alternative to the conventional methods for mosquito surveillance, mapping and sample image collection. Experimental results involving classification between mosquitoes and a predefined set of other bugs using multiple classification strategies demonstrate the efficacy and validity of the proposed approach with a maximum recall of 98%.

  14. Effect of levofloxacin, pazufloxacin, enrofloxacin, and meloxicam on the immunolocalization of ABCG-2 transporter protein in rabbit retina.

    Khan, Adil Mehraj; Rampal, Satyavan; Sood, Naresh Kumar

    2018-03-01

    Adenosine triphosphate-binding cassette (ABC) sub-family G member-2 (ABCG-2) is a transporter protein, implicated for multi-drug efflux from tissues. This study evaluated the effect of fluoroquinolones; levofloxacin, pazufloxacin and enrofloxacin, and non-steroidal anti-inflammatory drug, meloxicam; on the immunolocalization of ABCG-2 transporter protein of rabbit retinas. Thirty-two male rabbits were randomly divided in to eight groups. Control group was gavaged, 2% benzyl alcohol in 5% dextrose since these chemicals are excipients of the drug preparations used in the treatment groups of this study. Four groups were exclusively gavaged, levofloxacin hemihydrate (10 mg/kg body weight b.i.d 12 h), pazufloxacin mesylate (10 mg/kg body weight b.i.d 12 h), enrofloxacin (20 mg/kg body weight o.d.), and meloxicam (0.2 mg/kg body weight o.d.), respectively. Three other groups were co-gavaged meloxicam with above fluoroquinolones, respectively. These drugs were administered for 21 days. ABCG-2 immunolocalization was mild in the retinas of control and levofloxacin-alone-treated groups. The immunolocalization intensity was significantly higher in meloxicam-alone-treated group when compared to control and levofloxacin-alone-treated groups. Immunolocalization of this transporter increased in the levofloxacin-meloxicam co-treated group when compared to the levofloxacin-alone-treated group. Highest immunolocalization was observed in the enrofloxacin-meloxicam co-treated group although the immunolocalization of all treatment groups, except the levofloxacin-alone-treated group, was significantly higher than the control and levofloxacin-alone-treated groups.

  15. MosquitoMap and the Mal-area calculator: new web tools to relate mosquito species distribution with vector borne disease.

    Foley, Desmond H; Wilkerson, Richard C; Birney, Ian; Harrison, Stanley; Christensen, Jamie; Rueda, Leopoldo M

    2010-02-18

    Mosquitoes are important vectors of diseases but, in spite of various mosquito faunistic surveys globally, there is a need for a spatial online database of mosquito collection data and distribution summaries. Such a resource could provide entomologists with the results of previous mosquito surveys, and vector disease control workers, preventative medicine practitioners, and health planners with information relating mosquito distribution to vector-borne disease risk. A web application called MosquitoMap was constructed comprising mosquito collection point data stored in an ArcGIS 9.3 Server/SQL geodatabase that includes administrative area and vector species x country lookup tables. In addition to the layer containing mosquito collection points, other map layers were made available including environmental, and vector and pathogen/disease distribution layers. An application within MosquitoMap called the Mal-area calculator (MAC) was constructed to quantify the area of overlap, for any area of interest, of vector, human, and disease distribution models. Data standards for mosquito records were developed for MosquitoMap. MosquitoMap is a public domain web resource that maps and compares georeferenced mosquito collection points to other spatial information, in a geographical information system setting. The MAC quantifies the Mal-area, i.e. the area where it is theoretically possible for vector-borne disease transmission to occur, thus providing a useful decision tool where other disease information is limited. The Mal-area approach emphasizes the independent but cumulative contribution to disease risk of the vector species predicted present. MosquitoMap adds value to, and makes accessible, the results of past collecting efforts, as well as providing a template for other arthropod spatial databases.

  16. Modelling the impact of the long-term use of insecticide-treated bed nets on Anopheles mosquito biting time.

    Ferreira, Claudia P; Lyra, Silas P; Azevedo, Franciane; Greenhalgh, David; Massad, Eduardo

    2017-09-15

    Evidence of changing in biting and resting behaviour of the main malaria vectors has been mounting up in recent years as a result of selective pressure by the widespread and long-term use of insecticide-treated bed nets (ITNs), and indoor residual spraying. The impact of resistance behaviour on malaria intervention efficacy has important implications for the epidemiology and malaria control programmes. In this context, a theoretical framework is presented to understand the mechanisms determining the evolution of feeding behaviour under the pressure of use of ITNs. An agent-based stochastic model simulates the impact of insecticide-treated bed nets on mosquito fitness by reducing the biting rates, as well as increasing mortality rates. The model also incorporates a heritability function that provides the necessary genetic plasticity upon which natural selection would act to maximize the fitness under the pressure of the control strategy. The asymptotic equilibrium distribution of mosquito population versus biting time is shown for several daily uses of ITNs, and the expected disruptive selection on this mosquito trait is observed in the simulations. The relative fitness of strains that bite at much earlier time with respect to the wild strains, when a threshold of about 50% of ITNs coverage highlights the hypothesis of a behaviour selection. A sensitivity analysis has shown that the top three parameters that play a dominant role on the mosquito fitness are the proportion of individuals using bed nets and its effectiveness, the impact of bed nets on mosquito oviposition, and the mosquito genetic plasticity related to changing in biting time. By taking the evolutionary aspect into account, the model was able to show that the long-term use of ITNs, although representing an undisputed success in reducing malaria incidence and mortality in many affected areas, is not free of undesirable side effects. From the evolutionary point of view of the parasite virulence, it

  17. Larval midgut modifications associated with Bti resistance in the yellow fever mosquito using proteomic and transcriptomic approaches

    Tetreau Guillaume

    2012-06-01

    Full Text Available Abstract Background Bacillus thuringiensis var. israelensis (Bti is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of Diptera larvae. It is used worldwide for mosquito control. Resistance mechanisms of an Aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing Bti toxins were investigated in larval midguts at two levels: 1. gene transcription using DNA microarray and RT-qPCR and 2. differential expression of brush border membrane proteins using DIGE (Differential In Gel Electrophoresis. Results Several Bti Cry toxin receptors including alkaline phosphatases and N-aminopeptidases and toxin-binding V-ATPases exhibited altered expression levels in the resistant strain. The under-expression of putative Bti-receptors is consistent with Bt-resistance mechanisms previously described in Lepidoptera. Four soluble metalloproteinases were found under-transcribed together with a drastic decrease of metalloproteinases activity in the resistant strain, suggesting a role in resistance by decreasing the amount of activated Cry toxins in the larval midgut. Conclusions By combining transcriptomic and proteomic approaches, we detected expression changes at nearly each step of the ingestion-to-infection process, providing a short list of genes and proteins potentially involved in Bti-resistance whose implication needs to be validated. Collectively, these results open the way to further functional analyses to better characterize Bti-resistance mechanisms in mosquitoes.

  18. Microbial Pre-exposure and Vectorial Competence of Anopheles Mosquitoes

    Constentin Dieme

    2017-12-01

    Full Text Available Anopheles female mosquitoes can transmit Plasmodium, the malaria parasite. During their aquatic life, wild Anopheles mosquito larvae are exposed to a huge diversity of microbes present in their breeding sites. Later, adult females often take successive blood meals that might also carry different micro-organisms, including parasites, bacteria, and viruses. Therefore, prior to Plasmodium ingestion, the mosquito biology could be modulated at different life stages by a suite of microbes present in larval breeding sites, as well as in the adult environment. In this article, we highlight several naturally relevant scenarios of Anopheles microbial pre-exposure that we assume might impact mosquito vectorial competence for the malaria parasite: (i larval microbial exposures; (ii protist co-infections; (iii virus co-infections; and (iv pathogenic bacteria co-infections. In addition, significant behavioral changes in African Anopheles vectors have been associated with increasing insecticide resistance. We discuss how these ethological modifications may also increase the repertoire of microbes to which mosquitoes could be exposed, and that might also influence their vectorial competence. Studying Plasmodium–Anopheles interactions in natural microbial environments would efficiently contribute to refining the transmission risks.

  19. Temporal Coordination of Carbohydrate Metabolism during Mosquito Reproduction.

    Yuan Hou

    2015-07-01

    Full Text Available Hematophagous mosquitoes serve as vectors of multiple devastating human diseases, and many unique physiological features contribute to the incredible evolutionary success of these insects. These functions place high-energy demands on a reproducing female mosquito, and carbohydrate metabolism (CM must be synchronized with these needs. Functional analysis of metabolic gene profiling showed that major CM pathways, including glycolysis, glycogen and sugar metabolism, and citrate cycle, are dramatically repressed at post eclosion (PE stage in mosquito fat body followed by a sharply increase at post-blood meal (PBM stage, which were also verified by Real-time RT-PCR. Consistent to the change of transcript and protein level of CM genes, the level of glycogen, glucose and trehalose and other secondary metabolites are also periodically accumulated and degraded during the reproductive cycle respectively. Levels of triacylglycerols (TAG, which represent another important energy storage form in the mosquito fat body, followed a similar tendency. On the other hand, ATP, which is generated by catabolism of these secondary metabolites, showed an opposite trend. Additionally, we used RNA interference studies for the juvenile hormone and ecdysone receptors, Met and EcR, coupled with transcriptomics and metabolomics analyses to show that these hormone receptors function as major regulatory switches coordinating CM with the differing energy requirements of the female mosquito throughout its reproductive cycle. Our study demonstrates how, by metabolic reprogramming, a multicellular organism adapts to drastic and rapid functional changes.

  20. Larval diet affects mosquito development and permissiveness to Plasmodium infection.

    Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

    2016-12-02

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

  1. Toxicity of a plant based mosquito repellent/killer

    Singh, Prakash Raj; Mohanty, Manoj Kumar

    2012-01-01

    The mission to make humans less attractive to mosquitoes has fuelled decades of scientific research on mosquito behaviour and control. The search for the perfect topical insect repellent/killer continues. This analysis was conducted to review and explore the scientific information on toxicity produced by the ingredients/contents of a herbal product. In this process of systemic review the following methodology was applied. By doing a MEDLINE search with key words of selected plants, plant based insect repellents/killers pertinent articles published in journals and authentic books were reviewed. The World Wide Web and the Extension Toxicity Network database (IPCS-ITOX) were also searched for toxicology data and other pertinent information. Repellents do not all share a single mode of action and surprisingly little is known about how repellents act on their target insects. Moreover, different mosquito species may react differently to the same repellent. After analysis of available data and information on the ingredient, of the product in relation to medicinal uses, acute and chronic toxicity of the selected medicinal plants, it can be concluded that the ingredients included in the herbal product can be used as active agents against mosquitoes. If the product which contains the powder of the above said plants is applied with care and safety, it is suitable fo use as a mosquito repellent/killer. PMID:23554562

  2. West Nile Virus in Mosquitoes of Iranian Wetlands.

    Bagheri, Masoomeh; Terenius, Olle; Oshaghi, Mohammad Ali; Motazakker, Morteza; Asgari, Sassan; Dabiri, Farrokh; Vatandoost, Hassan; Mohammadi Bavani, Mulood; Chavshin, Ali Reza

    2015-12-01

    The West Nile virus (WNV) transmission cycle includes a wide range of migratory wetland birds as reservoirs, mosquitoes as biological vectors, and equines and humans as dead-end hosts. Despite the presence of potential vector species, there is no information about the existence of WNV in mosquito vectors in Iran. The Iranian West Azerbaijan Province is located in the northwestern part of Iran and has borders with Turkey, Iraq, Armenia, and the Republic of Azerbaijan. The current study was conducted to identify the wetland mosquitoes of the West Azerbaijan Province and their infection with WNV. In this study, 2143 specimens were collected, comprising 1541 adults and 602 larvae. Six species belonging to four genera were collected and identified: Anopheles maculipennis sensu lato (s.l.), Culex (Cx.) hortensis, Cx. pipiens s.l., Cx. theileri, Culiseta longiareolata, and Aedes (Ae.) (Ochlerotatus) caspius. In total, 45 pools of mosquitoes were examined. Two of the adult pools collected from the same location showed the presence of WNV in Ae. (Och.) caspius, from Sangar, Makoo County, as confirmed by PCR and sequencing. Due to the discovery of WNV in the mosquito population of the region, and the presence of wetlands and significant populations of migratory birds, the health sector should carefully monitor the factors involved in the cycle of this disease.

  3. Resource Limitation, Controphic Ostracod Density and Larval Mosquito Development.

    Raylea Rowbottom

    Full Text Available Aquatic environments can be restricted with the amount of available food resources especially with changes to both abiotic and biotic conditions. Mosquito larvae, in particular, are sensitive to changes in food resources. Resource limitation through inter-, and intra-specific competition among mosquitoes are known to affect both their development and survival. However, much less is understood about the effects of non-culicid controphic competitors (species that share the same trophic level. To address this knowledge gap, we investigated and compared mosquito larval development, survival and adult size in two experiments, one with different densities of non-culicid controphic conditions and the other with altered resource conditions. We used Aedes camptorhynchus, a salt marsh breeding mosquito and a prominent vector for Ross River virus in Australia. Aedes camptorhynchus usually has few competitors due to its halo-tolerance and distribution in salt marshes. However, sympatric ostracod micro-crustaceans often co-occur within these salt marshes and can be found in dense populations, with field evidence suggesting exploitative competition for resources. Our experiments demonstrate resource limiting conditions caused significant increases in mosquito developmental times, decreased adult survival and decreased adult size. Overall, non-culicid exploitation experiments showed little effect on larval development and survival, but similar effects on adult size. We suggest that the alterations of adult traits owing to non-culicid controphic competition has potential to extend to vector-borne disease transmission.

  4. Bcl-2 expression during the development and degeneration of RCS rat retinae.

    Sharma, R K

    2001-12-14

    In various hereditary retinal degenerations, including that in Royal College of Surgeons (RCS) rats, the photoreceptors ultimately die by apoptosis. Bcl-2 is one of the genes, which regulates apoptosis and is thought to promote survival of cells. This study has investigated the developmental expression of Bcl-2 in RCS rat, which is a well-studied animal model for hereditary retinal degeneration. An antibody against Bcl-2 was used for its immunohistochemical localization in dystrophic RCS rat retinae from postnatal (PN) days 4, 7, 13, 35, 45, 70, 202 and 14 months. Results were compared with Bcl-2 localization in congenic non-dystrophic rats from PN 4, 7, 13, 44, 202 and 14 months. Bcl-2 immunoreactivity in non-dystrophic retinae was already present in PN 4 retinae in the nerve fiber layer (presumably in the endfeet of immature Müller cells) and in the proximal parts of certain radially aligned neuroepithelial cells/immature Müller cell radial processes. With increasing age the immunoreactivity in relatively more mature Müller cell radial processes spread distally towards the outer retina and between PN 13 and 44 it reached the adult distribution. No cell bodies in the ganglion cell layer were found to be immunoreactive. Expression of Bcl-2 immunoreactivity in dystrophic RCS rat retinae closely resembled that of non-dystrophic retinae. No immunoreactivity was seen in photoreceptors or retinal pigment epithelium in dystrophic or non-dystrophic retinae. In conclusion, Bcl-2 expression is not altered, either in terms of its chronology or the cell type expressing it, during retinal degeneration in RCS rats.

  5. Effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats

    Xiao Liu

    2016-01-01

    ABSTRACT Objective:To study the effect of ozone therapy on cell apoptosis and angiogenesis in retina tissue of diabetic retinopathy rats.Methods:SD rats were selected as experimental animals and divided into control group, model group and ozone group, and after diabetic models were built, ozone enema was conducted. Retina tissue was collected, TUNEL kits were used to detect the number of apoptotic cells, and Elisa kits were used to detect the contents of nerve damage molecules, angiogenesis-related molecules and endoplasmic reticulum stress molecules. Results:The number of apoptotic cells in retina tissue of model group was significantly more than that of control group, and the number of apoptotic cells in retina tissue of ozone group was significantly less than that of model group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of model group were significantly higher than those of control group, and PEDF content was lower than that of control group; NgR, NR2B, ERK1, ERK2, GFAP, VEGF, STAT-3, HIF-1α, Apelin, APJ, PERK, IRE-1α, ATF-6, eIF2α and XBP-1 contents in retina tissue of ozone group were significantly lower than those of model group, and PEDF content was higher than that of model group.Conclusion:Ozone therapy can reduce the number of apoptotic cells while reduce nerve cell injury and inhibit angiogenesis and endoplasmic reticulum stress in retina tissue of diabetic rats.

  6. Cold Shock Proteins Are Expressed in the Retina Following Exposure to Low Temperatures.

    Ignacio M Larrayoz

    Full Text Available Hypothermia has been proposed as a therapeutic intervention for some retinal conditions, including ischemic insults. Cold exposure elevates expression of cold-shock proteins (CSP, including RNA-binding motif protein 3 (RBM3 and cold inducible RNA-binding protein (CIRP, but their presence in mammalian retina is so far unknown. Here we show the effects of hypothermia on the expression of these CSPs in retina-derived cell lines and in the retina of newborn and adult rats. Two cell lines of retinal origin, R28 and mRPE, were exposed to 32°C for different time periods and CSP expression was measured by qRT-PCR and Western blotting. Neonatal and adult Sprague-Dawley rats were exposed to a cold environment (8°C and expression of CSPs in their retinas was studied by Western blotting, multiple inmunofluorescence, and confocal microscopy. RBM3 expression was upregulated by cold in both R28 and mRPE cells in a time-dependent fashion. On the other hand, CIRP was upregulated in R28 cells but not in mRPE. In vivo, expression of CSPs was negligible in the retina of newborn and adult rats kept at room temperature (24°C. Exposure to a cold environment elicited a strong expression of both proteins, especially in retinal pigment epithelium cells, photoreceptors, bipolar, amacrine and horizontal cells, Müller cells, and ganglion cells. In conclusion, CSP expression rapidly rises in the mammalian retina following exposure to hypothermia in a cell type-specific pattern. This observation may be at the basis of the molecular mechanism by which hypothermia exerts its therapeutic effects in the retina.

  7. Transgenic mosquitoes and the fight against malaria: managing technology push in a turbulent GMO world

    Knols, B.G.J.; Bossin, H.C.; Mukabana, W.R.; Robinson, A.S.

    2007-01-01

    Genetic modification (GM) of mosquitoes (which renders them genetically modified organisms, GMOs) offers opportunities for controlling malaria. Transgenic strains of mosquitoes have been developed and evaluation of these to 1) replace or suppress wild vector populations and 2) reduce transmission

  8. Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China

    Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun

    2017-01-01

    In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies. PMID:28430562

  9. Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China.

    Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun; Chen, Xiao-Guang

    2017-07-01

    In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies.

  10. Don't Let the Bugs Bite: Preventing Dengue and Other Diseases Spread by Mosquitoes

    This year (2007) CDC is receiving a great many reports of cases of Dengue fever, which is spread by mosquitoes. This podcast discusses ways travelers to the tropics can protect themselves from mosquito bites.

  11. Sugar and Multivitamin Diet Effects on The Longevity and Mating Capacity of Laboratory-Reared Male Anopheline Mosquitoes.

    Phasomkusolsil, Siriporn; Pantuwatana, Kanchana; Tawong, Jaruwan; Khongtak, Weeraphan; Kertmanee, Yossasin; Monkanna, Nantaporn; Khaosanorh, Sakon; Wanja, Elizabeth W; Davidson, Silas A

    2017-09-01

    Successful mating by male mosquitoes is dependent on several factors, with sugar feeding being particularly important. The effect of ingested vitamins on adult male mosquitoes is poorly understood. This laboratory study used 3 anopheline species, Anopheles campestris, An. dirus, and An. sawadwongporni, to study the effect of sugar and vitamins on male longevity, copulation, and fecundity. Males were fed 1 of 5 diets containing different combinations of sugar and vitamins: 10% glucose, 10% sucrose, 10% multivitamin syrup, 10% multivitamin syrup + 10% glucose, and 10% multivitamin syrup + 10% sucrose. The longevity of males was measured for a period of 15 days. Forced mating was used to simulate copulation, and fecundity was measured by counting the number of eggs oviposited and the hatch rate of larvae. The longevity of An. campestris and An. dirus was greatest when fed a diet of 10% multivitamin syrup + 10% glucose, and the longevity of An. sawadwongporni was greatest when fed a diet of 10% multivitamin syrup + 10% sucrose. The 1st mating routinely produced the most viable eggs when males were mated with several females. The diet of 10% multivitamin syrup + 10% sucrose produced numerically greater egg production and larval emergence for all 3 species, although this was not always statistically significant due to variability and small sample size. These results indicate that the addition of multivitamin syrup to sucrose may produce healthier and more fit male anophelines. This has potential implications for increasing insectary operations and improving the fitness of laboratory-reared male mosquitoes that will be released for mosquito and disease-pathogen control studies.

  12. Indoor application of attractive toxic sugar bait (ATSB in combination with mosquito nets for control of pyrethroid-resistant mosquitoes.

    Zachary P Stewart

    Full Text Available BACKGROUND: Attractive toxic sugar bait (ATSB sprayed onto vegetation has been successful in controlling Anopheles mosquitoes outdoors. Indoor application of ATSB has yet to be explored. The purpose of this study was to determine whether ATSB stations positioned indoors have the potential to kill host-seeking mosquitoes and constitute a new approach to control of mosquito-borne diseases. METHODS: Insecticides were mixed with dyed sugar solution and tested as toxic baits against Anopheles arabiensis, An. Gambiae s.s. and Culex quinquefasciatus in feeding bioassay tests to identify suitable attractant-insecticide combinations. The most promising ATSB candidates were then trialed in experimental huts in Moshi, Tanzania. ATSB stations were hung in huts next to untreated mosquito nets occupied by human volunteers. The proportions of mosquitoes killed in huts with ATSB treatments relative to huts with non-insecticide control treatments huts were recorded, noting evidence of dye in mosquito abdomens. RESULTS: In feeding bioassays, chlorfenapyr 0.5% v/v, boric acid 2% w/v, and tolfenpyrad 1% v/v, mixed in a guava juice-based bait, each killed more than 90% of pyrethroid-susceptible An. Gambiae s.s. and pyrethroid-resistant An. arabiensis and Cx. quinquefasciatus. In the hut trial, mortality rates of the three ATSB treatments ranged from 41-48% against An. arabiensis and 36-43% against Cx. quinquefasciatus and all were significantly greater than the control mortalities: 18% for An. arabiensis, 7% for Cx. quinquefasciatus (p<0.05. Mortality rates with ATSB were comparable to those with long lasting insecticidal nets previously tested against the same species in this area. CONCLUSIONS: Indoor ATSB shows promise as a supplement to mosquito nets for controlling mosquitoes. Indoor ATSB constitute a novel application method for insecticide classes that act as stomach poisons and have not hitherto been exploited for mosquito control. Combined with LLIN, indoor

  13. Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm

    Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

    2014-01-01

    We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same ...

  14. The effect of pesticide residue on caged mosquito bioassays.

    Barber, J A S; Greer, Mike; Coughlin, Jamie

    2006-09-01

    Wind tunnel experiments showed that secondary pickup of insecticide residue by mosquitoes in cage bioassays had a significant effect on mortality. Cage bioassays using adult Ochlerotatus taeniorhynchus (Wiedemann) investigated the effect of exposure time to a contaminated surface. Cages were dosed in a wind tunnel using the LC50 for naled (0.124 mg a.i./ml) and an LC25 (0.0772 mg a.i./ml) for naled. Half of the bioassay mosquitoes were moved directly into clean cages with the other half remaining in the sprayed, hence contaminated, cage. Treatment mortality was assessed at 8, 15, 30, 60, 120, 240, and 1,440 min postapplication. Cage contamination had a significant effect on mosquito mortality for both the LC25 and LC50 between 15 and 30 min postapplication.

  15. Viral Interference and Persistence in Mosquito-Borne Flaviviruses

    Juan Santiago Salas-Benito

    2015-01-01

    Full Text Available Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.

  16. Hypersensitivity to mosquito bite manifested as Skeeter syndrome

    Rafael Pérez-Vanzzini

    2015-02-01

    Full Text Available The reactions to mosquito bites are immunological reactions with involvement of IgE, IgG and T cells mediated hypersensitivity. These reactions are common and range from small local reactions, large local reactions to systemic allergic reactions. Skeeter syndrome is defined as a large local induced inflammatory reaction to mosquito bite and sometimes accompanied by systemic symptoms such as fever and vomiting. Diagnosis is based on clinical history and physical examination, supported by the identification of specific IgE by skin testing. Treatment includes prevention, antihistamines and steroids in some cases. Specific immunotherapy still requires further study. This paper reports two cases of patients with hypersensitivity reactions to mosquito bites, which were evaluated in our center presenting positive skin tests.

  17. Evaluation of a Noncontact, Alternative Mosquito Repellent Assay System.

    Tisgratog, Rungarun; Kongmee, Monthathip; Sanguanpong, Unchalee; Prabaripai, Atchariya; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2016-09-01

    A novel noncontact repellency assay system (NCRAS) was designed and evaluated as a possible alternative method for testing compounds that repel or inhibit mosquitoes from blood feeding. Deet and Aedes aegypti were used in a controlled laboratory setting. Using 2 study designs, a highly significant difference were seen between deet-treated and untreated skin placed behind the protective screens, indicating that deet was detected and was acting as a deterrence to mosquito landing and probing behavior. However, a 2nd study showed significant differences between protected (behind a metal screen barrier) and unprotected (exposed) deet-treated forearms, indicating the screen mesh might restrict the detection of deet and thus influences landing/biting response. These findings indicate the prototype NCRAS shows good promise but requires further evaluation and possible modification in design and testing protocol to achieve more desirable operational attributes in comparison with direct skin-contact repellency mosquito assays.

  18. Gradual diffusive capture: slow death by many mosquito bites

    Redner, S; Bénichou, O

    2014-01-01

    We study the dynamics of a single diffusing particle (a ‘man’) with diffusivity D M that is attacked by another diffusing particle (a ‘mosquito’) with fixed diffusivity D m . Each time the mosquito meets and bites the man, the diffusivity of the man is reduced by a fixed amount, while the diffusivity of the mosquito is unchanged. The mosquito is also displaced by a small distance ±a with respect to the man after each encounter. The man is defined as dead when D M reaches zero. At the moment when the man dies, his probability distribution of displacements x is given by a Cauchy form, which asymptotically decays as x −2 , while the distribution of times t when the man dies decays asymptotically as t −3/2 , which has the same form as the one-dimensional first-passage probability. (paper)

  19. Periodic dynamic systems for infected hosts and mosquitoes

    Oliva W. M.

    1996-01-01

    Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.

  20. Periodic dynamic systems for infected hosts and mosquitoes

    W. M. Oliva

    1996-06-01

    Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.

  1. Wnt signaling in form deprivation myopia of the mice retina.

    Mingming Ma

    Full Text Available BACKGROUND: The canonical Wnt signaling pathway plays important roles in cellular proliferation and differentiation, axonal outgrowth, cellular maintenance in retinas. Here we test the hypothesis that elements of the Wnt signaling pathway are involved in the regulation of eye growth and prevention of myopia, in the mouse form-deprivation myopia model. METHODOLOGY/PRINCIPAL FINDINGS: (1 One hundred twenty-five C57BL/6 mice were randomly distributed into form-deprivation myopia and control groups. Form-deprivation myopia (FDM was induced by suturing the right eyelid, while the control group received no treatment. After 1, 2, and 4 weeks of treatment, eyes were assessed in vivo by cycloplegic retinoscopic refraction and axial length measurement by photography or A-scan ultrasonography. Levels of retinal Wnt2b, Fzd5 and β-catenin mRNA and protein were evaluated using RT-PCR and western blotting, respectively. (2 Another 96 mice were divided into three groups: control, drugs-only, and drugs+FDM (by diffuser. Experimentally treated eyes in the last two groups received intravitreal injections of vehicle or the proteins, DKK-1 (Wnt-pathway antagonist or Norrin (Wnt-pathway agonist, once every three days, for 4 injections total. Axial length and retinoscopic refraction were measured on the 14th day of form deprivation. Following form-deprivation for 1, 2, and 4 weeks, FDM eyes had a relatively myopic refractive error, compared with contralateral eyes. There were no significant differences in refractive error between right and left eye in control group. The amounts of Wnt2b, Fzd5 and β-catenin mRNA and protein were significantly greater in form-deprived myopia eyes than in control eyes.DKK-1 (antagonist reduced the myopic shift in refractive error and increase in axial elongation, whereas Norrin had the opposite effect in FDM eyes. CONCLUSIONS/SIGNIFICANCE: Our studies provide the first evidence that the Wnt2b signaling pathway may play a role in the

  2. Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas.

    Chintalapudi, Sumana R; Wang, XiaoFei; Li, Huiling; Lau, Yin H Chan; Williams, Robert W; Jablonski, Monica M

    2016-01-01

    Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans -acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5 , expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5-immunopositive cones were

  3. Genetic and immunohistochemical analysis of HSPA5 in mouse and human retinas

    Chintalapudi, Sumana R.; Wang, XiaoFei; Li, Huiling; Lau, Yin H. Chan; Williams, Robert W.; Jablonski, Monica M.

    2016-01-01

    Purpose Photoreceptor degenerative diseases are among the leading causes of vision loss. Although the causative genetic mutations are often known, mechanisms leading to photoreceptor degeneration remain poorly defined. We have previously demonstrated that the photoreceptor membrane-associated protein XAP-1 antigen is a product of the HSPA5 gene. In this study, we used systems genetic methods, statistical modeling, and immunostaining to identify and analyze candidate genes that modulate Hspa5 expression in the retina. Methods Quantitative trait locus (QTL) mapping was used to map the genomic region that regulates Hspa5 in the cross between C57BL/6J X DBA/2J mice (BXD) genetic reference panel. The stepwise refinement of candidate genes was based on expression QTL mapping, gene expression correlation analyses (direct and partial), and analysis of regional sequence variants. The subcellular localization of candidate proteins and HSPA5 in mouse and human retinas was evaluated by immunohistochemistry. Differences in the localization of extracellular HSPA5 were assessed between healthy human donor and atrophic age-related macular degeneration (AMD) donor eyes. Results In the eyes of healthy mice, extracellular HSPA5 was confined to the area around the cone photoreceptor outer segments. Mapping variation in Hspa5 mRNA expression levels in the retina revealed a statistically significant trans-acting expression QTL (eQTL) on Chromosome 2 (Chr 2) and a suggestive locus on Chr 15. Sulf2 on Chr 2 was the strongest candidate gene based on partial correlation analysis, Pearson correlation with Hspa5, expression levels in the retina, a missense variant in exon 14, and its reported function in the extracellular matrix and interphotoreceptor matrix. SULF2 is localized to the rod and cone photoreceptors in both human and mouse retinas. In human retinas with no pathology, extracellular HSPA5 was localized around many cones within the macular area. In contrast, fewer HSPA5

  4. CLRN1 is nonessential in the mouse retina but is required for cochlear hair cell development.

    Scott F Geller

    2009-08-01

    Full Text Available Mutations in the CLRN1 gene cause Usher syndrome type 3 (USH3, a human disease characterized by progressive blindness and deafness. Clarin 1, the protein product of CLRN1, is a four-transmembrane protein predicted to be associated with ribbon synapses of photoreceptors and cochlear hair cells, and recently demonstrated to be associated with the cytoskeleton. To study Clrn1, we created a Clrn1 knockout (KO mouse and characterized the histological and functional consequences of Clrn1 deletion in the retina and cochlea. Clrn1 KO mice do not develop a retinal degeneration phenotype, but exhibit progressive loss of sensory hair cells in the cochlea and deterioration of the organ of Corti by 4 months. Hair cell stereocilia in KO animals were longer and disorganized by 4 months, and some Clrn1 KO mice exhibited circling behavior by 5-6 months of age. Clrn1 mRNA expression was localized in the retina using in situ hybridization (ISH, laser capture microdissection (LCM, and RT-PCR. Retinal Clrn1 transcripts were found throughout development and adulthood by RT-PCR, although expression peaked at P7 and declined to undetectable levels in adult retina by ISH. LCM localized Clrn1 transcripts to the retinas inner nuclear layer, and WT levels of retinal Clrn1 expression were observed in photoreceptor-less retinas. Examination of Clrn1 KO mice suggests that CLRN1 is unnecessary in the murine retina but essential for normal cochlear development and function. This may reflect a redundancy in the mouse retina not present in human retina. In contrast to mouse KO models of USH1 and USH2, our data indicate that Clrn1 expression in the retina is restricted to the Müller glia. This is a novel finding, as most retinal degeneration associated proteins are expressed in photoreceptors, not in glia. If CLRN1 expression in humans is comparable to the expression pattern observed in mice, this is the first report of an inner retinal protein that, when mutated, causes retinal

  5. Evolutionary enhancement of Zika virus infectivity in Aedes aegypti mosquitoes.

    Liu, Yang; Liu, Jianying; Du, Senyan; Shan, Chao; Nie, Kaixiao; Zhang, Rudian; Li, Xiao-Feng; Zhang, Renli; Wang, Tao; Qin, Cheng-Feng; Wang, Penghua; Shi, Pei-Yong; Cheng, Gong

    2017-05-25

    Zika virus (ZIKV) remained obscure until the recent explosive outbreaks in French Polynesia (2013-2014) and South America (2015-2016). Phylogenetic studies have shown that ZIKV has evolved into African and Asian lineages. The Asian lineage of ZIKV was responsible for the recent epidemics in the Americas. However, the underlying mechanisms through which ZIKV rapidly and explosively spread from Asia to the Americas are unclear. Non-structural protein 1 (NS1) facilitates flavivirus acquisition by mosquitoes from an infected mammalian host and subsequently enhances viral prevalence in mosquitoes. Here we show that NS1 antigenaemia determines ZIKV infectivity in its mosquito vector Aedes aegypti, which acquires ZIKV via a blood meal. Clinical isolates from the most recent outbreak in the Americas were much more infectious in mosquitoes than the FSS13025 strain, which was isolated in Cambodia in 2010. Further analyses showed that these epidemic strains have higher NS1 antigenaemia than the FSS13025 strain because of an alanine-to-valine amino acid substitution at residue 188 in NS1. ZIKV infectivity was enhanced by this amino acid substitution in the ZIKV FSS13025 strain in mosquitoes that acquired ZIKV from a viraemic C57BL/6 mouse deficient in type I and II interferon (IFN) receptors (AG6 mouse). Our results reveal that ZIKV evolved to acquire a spontaneous mutation in its NS1 protein, resulting in increased NS1 antigenaemia. Enhancement of NS1 antigenaemia in infected hosts promotes ZIKV infectivity and prevalence in mosquitoes, which could have facilitated transmission during recent ZIKV epidemics.

  6. Effect of high-intensity irradiation from dental photopolymerization on the isolated and superfused vertebrate retina.

    Rassaei, Mohammad; Thelen, Martin; Abumuaileq, Ramzi; Hescheler, Jürgen; Lüke, Matthias; Schneider, Toni

    2013-03-01

    Light or electromagnetic radiation may damage the neurosensory retina during irradiation of photopolymerizing resinous materials. Direct and indirect effects of irradiation emitted from polymerisation curing light may represent a severe risk factor for the eyes and the skin of the lamp operators, as well as for the patient's oral mucosa. Bovine superfused retinas were used to record their light-evoked electroretinogram (ERG) as ex vivo ERGs. Both the a- and the b-waves were used as indicators for retinal damage on the functional level. The isolated retinas were routinely superfused with a standard nutrient solution under normoglycemic conditions (5 mM D-glucose). The change in the a- and b-wave amplitude and implicit time, caused by low and high intensity irradiation, was calculated and followed over time. From the results, it can be deduced that the irradiation from LED high-power lamps affects severely the normal physiological function of the bovine retina. Irradiations of 1,200 lx irreversibly damaged the physiological response. In part, this may be reversible at lower intensities, but curing without using the appropriate filter will bleach the retinal rhodopsin to a large extent within 20 to 40 s of standard application times. Constant exposure to intense ambient irradiation affects phototransduction (a-wave) as well as transretinal signalling. The proper use of the UV- and blue-light filtering device is highly recommended, and may prevent acute and long lasting damage of the neurosensory retina.

  7. Some indications of structural damage in retina by heavy ion radiation

    Nelson, A.C.; Hayes, T.L.; Tobias, C.A.; Yang, T.C.

    1981-01-01

    At the Lawrence Berkeley Laboratory Bevalac Facility, iron nuclei were accelerated to an energy of 600 MeV/amu. The beam of iron thus obtained was used to irradiate living biological specimens in order to study possible microscopic tissue damage with the aid of SEM. The experiments involved total head irradiation of live rats which were subsequently returned to their cages to remain for 1 day and 30 days before further examination. After the 1 day and 30 day waits, both eyes were enucleated and placed in chemical fixative followed by ethanol dehydration and critical point drying. Retinas were carefully removed from the eye cups and loaded separately on aluminum stubs which were sputter coated. SEM of the 1 day and 30 day retinas revealed lesions which were not found at all in control retinas. The 1 day and 30 day retinas manifest regions where outer rod segments were missing or rearranged. A single energetic iron nucleus may be capable of generating a retinal lesion which becomes enlarged as biological processes intervene during the 1 day and 30 day waits. Being composed of highly specialized nerve cells, retinas cannot regenerate following irradiation which severely damages the rod cells. Thus one would expect the observed radiation induced retinal lesions to correspond to permanent tissue damage and possible loss of visual acuity in the intact animal

  8. FPGA-Based Real Time, Multichannel Emulated-Digital Retina Model Implementation

    Zsolt Vörösházi

    2009-01-01

    Full Text Available The function of the low-level image processing that takes place in the biological retina is to compress only the relevant visual information to a manageable size. The behavior of the layers and different channels of the neuromorphic retina has been successfully modeled by cellular neural/nonlinear networks (CNNs. In this paper, we present an extended, application-specific emulated-digital CNN-universal machine (UM architecture to compute the complex dynamic of this mammalian retina in video real time. The proposed emulated-digital implementation of multichannel retina model is compared to the previously developed models from three key aspects, which are processing speed, number of physical cells, and accuracy. Our primary aim was to build up a simple, real-time test environment with camera input and display output in order to mimic the behavior of retina model implementation on emulated digital CNN by using low-cost, moderate-sized field-programmable gate array (FPGA architectures.

  9. Frequency of Toxoplasma gondii in the retina in eye banks in Brazil.

    Costa, Deise F; Nascimento, Heloisa; Sutili, Aline; Nobrega, Fernando A J; Fowler, Flavio; Nobrega, Mario Junqueira; Garrido, Cristina; de Oliveira Dias, Janaina; Adán, Consuelo B D; Rizzo, Luiz Vicente; Silveira, Claudio; Belfort, Rubens; Commodaro, Alessandra G

    2017-07-01

    Ocular toxoplasmosis is the main cause of posterior uveitis worldwide frequently leading to vision loss. In Brazil, the seroprevalence of Toxoplasma gondii infection ranges from 50 to 80% depending of the region studied. The frequency of toxoplasmic retinal scar may reach 18% of the adults in the South of Brazil. Our goal was to determine the frequency of T. gondii DNA in retinas from eye banks from different regions in Brazil. A total of 162 eyes were obtained from eye banks in Manaus (n = 60), Sao Paulo (n = 60), Chapeco (n = 26), and Joinville (n = 16). The retinas were macroscopically analyzed and collected for DNA extraction. Real-time PCR (qPCR) was performed using the T. gondii B1 marker. By qPCR, a higher frequency of T. gondii DNA in the retinas from the eye bank of Joinville (25%) was found when compared to Manaus (5%). The retinas from Sao Paulo and Chapeco were qPCR negative. Clinical examination determined the retina lesions to be compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), Sao Paulo (6.7%), and Chapeco (15.4%).

  10. Training and professional profile of retinologists in Spain: Retina 2 project, Report 4.

    Pastor, J Carlos; Fernández, Itziar; Rojas, Jimena; Coco, Rosa; Sanabria, Maria R; Rodríguez-de la Rúa, Enrique; Sánchez, Diego; Valverde, Carmen; Sala-Puigdollers, Anna

    2011-01-01

    Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties. After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined. Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%). Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5%) practiced anterior segment surgery, and 78.7% declared skills in vitrectomy. We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.

  11. Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography.

    Garcia, Jose Mauricio Botto de Barros; Isaac, David Leonardo Cruvinel; Sardeiro, Tainara; Aquino, Érika; Avila, Marcos

    2017-01-01

    This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980), an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

  12. Autofluorescence from the outer retina and subretinal space: hypothesis and review.

    Spaide, Richard

    2008-01-01

    To review the pathophysiologic principles underlying increased autofluorescence from the outer retina and subretinal space using selected diseases as examples. The ocular imaging information and histopathologic features, when known, were integrated for diseases causing increased autofluorescence from the outer retina and subretinal space. Inferences were taken from this information and used to create a classification scheme. These diseases are principally those that cause separation of the outer retina from the retinal pigment epithelium, thereby preventing proper phagocytosis of photoreceptor outer segments. The separation can arise from increased exudation into the subretinal space or inadequate removal of fluid from the subretinal space. Lack of normal outer segment processing initially leads to increased accumulation of outer segments on the outer retina and subretinal space. Over time, this material is visible as an increasingly thick coating on the outer retina, is yellow, and is autofluorescent. Over time, atrophy develops with thinning of the deposited material and decreasing autofluorescence. The accumulated material is ultimately capable of inducing damage to the retinal pigment epithelium. Diseases causing accumulation of the material include central serous chorioretinopathy, vitelliform macular dystrophy, acute exudative polymorphous vitelliform maculopathy, choroidal tumors, and vitreomacular traction syndrome. The physical separation of the retinal outer segments from the retinal pigment epithelium hinders proper phagocytosis of the outer segments. Accumulation of the shed but not phagocytized outer segments plays a role in disease manifestations for a number of macular diseases.

  13. Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography

    Jose Mauricio Botto de Barros Garcia

    Full Text Available ABSTRACT This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980, an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

  14. Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye.

    Sharma, Robin; Williams, David R; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J

    2016-02-01

    Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.

  15. Local edge detectors: a substrate for fine spatial vision at low temporal frequencies in rabbit retina.

    van Wyk, Michiel; Taylor, W Rowland; Vaney, David I

    2006-12-20

    Visual acuity is limited by the size and density of the smallest retinal ganglion cells, which correspond to the midget ganglion cells in primate retina and the beta-ganglion cells in cat retina, both of which have concentric receptive fields that respond at either light-On or light-Off. In contrast, the smallest ganglion cells in the rabbit retina are the local edge detectors (LEDs), which respond to spot illumination at both light-On and light-Off. However, the LEDs do not predominate in the rabbit retina and the question arises, what role do they play in fine spatial vision? We studied the morphology and physiology of LEDs in the isolated rabbit retina and examined how their response properties are shaped by the excitatory and inhibitory inputs. Although the LEDs comprise only approximately 15% of the ganglion cells, neighboring LEDs are separated by 30-40 microm on the visual streak, which is sufficient to account for the grating acuity of the rabbit. The spatial and temporal receptive-field properties of LEDs are generated by distinct inhibitory mechanisms. The strong inhibitory surround acts presynaptically to suppress both the excitation and the inhibition elicited by center stimulation. The temporal properties, characterized by sluggish onset, sustained firing, and low bandwidth, are mediated by the temporal properties of the bipolar cells and by postsynaptic interactions between the excitatory and inhibitory inputs. We propose that the LEDs signal fine spatial detail during visual fixation, when high temporal frequencies are minimal.

  16. Comparative proteomic analyses of macular and peripheral retina of cynomolgus monkeys (Macaca fascicularis).

    Okamoto, Haru; Umeda, Shinsuke; Nozawa, Takehiro; Suzuki, Michihiro T; Yoshikawa, Yasuhiro; Matsuura, Etsuko T; Iwata, Takeshi

    2010-01-01

    The central region of the primate retina is called the macula. The fovea is located at the center of the macula, where the photoreceptors are concentrated to create a neural network adapted for high visual acuity. Damage to the fovea, e.g., by macular dystrophies and age-related macular degeneration, can reduce central visual acuity. The molecular mechanisms leading to these diseases are most likely dependent on the proteins in the macula which differ from those in the peripheral retina in expression level. To investigate whether the distribution of proteins in the macula is different from the peripheral retina, proteomic analyses of tissues from these two regions of cynomolgus monkeys were compared. Two-dimensional gel electrophoresis and mass spectrometry identified 26 proteins that were present only in the macular gel spots. The expression levels of five proteins, cone photoreceptor specific arrestin-C, gamma-synuclein, epidermal fatty acid binding protein, tropomyosin 1alpha chain, and heterogeneous nuclear ribonucleoproteins A2/B1, were significantly higher in the macula than in the peripheral retina. Immunostaining of macula sections by antibodies to each identified protein revealed unique localization in the retina, retinal pigment epithelial cells and the choroidal layer. Some of these proteins were located in cells with higher densities in the macula. We suggest that it will be important to study these proteins to determine their contribution to the pathogenesis and progression of macula diseases.

  17. HB-EGF is necessary and sufficient for Müller glia dedifferentiation and retina regeneration

    Wan, Jin; Ramachandran, Rajesh; Goldman, Daniel

    2011-01-01

    Summary Müller glia (MG) dedifferentiation into a cycling population of multipotent progenitors is crucial to zebrafish retina regeneration. The mechanisms underlying MG dedifferentiation are unknown. Here we report that heparin-binding epidermal-like growth factor (HB-EGF) is rapidly induced in MG residing at the injury site and that proHB-EGF ectodomain shedding is necessary for retina regeneration. Remarkably, HB-EGF stimulates the formation of multipotent MG-derived progenitors in the uninjured retina. We show that HB-EGF mediates its effects via an EGFR/MAPK signal transduction cascade that regulates the expression of regeneration-associated genes, like ascl1a and pax6b. We also uncover an HB-EGF/Ascl1a/Notch/hb-egfa signaling loop that helps define the zone of injury-responsive MG. Finally, we show that HB-EGF acts upstream of the Wnt/β-catenin signaling cascade that controls progenitor proliferation. These data provide a link between extracellular signaling and regeneration-associated gene expression in the injured retina and suggest strategies for stimulating retina regeneration in mammals. PMID:22340497

  18. The Retinome – Defining a reference transcriptome of the adult mammalian retina/retinal pigment epithelium

    Goetz Thomas

    2004-07-01

    Full Text Available Abstract Background The mammalian retina is a valuable model system to study neuronal biology in health and disease. To obtain insight into intrinsic processes of the retina, great efforts are directed towards the identification and characterization of transcripts with functional relevance to this tissue. Results With the goal to assemble a first genome-wide reference transcriptome of the adult mammalian retina, referred to as the retinome, we have extracted 13,037 non-redundant annotated genes from nearly 500,000 published datasets on redundant retina/retinal pigment epithelium (RPE transcripts. The data were generated from 27 independent studies employing a wide range of molecular and biocomputational approaches. Comparison to known retina-/RPE-specific pathways and established retinal gene networks suggest that the reference retinome may represent up to 90% of the retinal transcripts. We show that the distribution of retinal genes along the chromosomes is not random but exhibits a higher order organization closely following the previously observed clustering of genes with increased expression. Conclusion The genome wide retinome map offers a rational basis for selecting suggestive candidate genes for hereditary as well as complex retinal diseases facilitating elaborate studies into normal and pathological pathways. To make this unique resource freely available we have built a database providing a query interface to the reference retinome 1.

  19. EPA Registers the Wolbachia ZAP Strain in Live Male Asian Tiger Mosquitoes

    EPA registered a new mosquito biopesticide – ZAP Males® - that can reduce local populations of the type of mosquito (Aedes albopictus, or Asian Tiger Mosquitoes) that can spread numerous diseases of significant human health concern, including the Zika viru

  20. Biodiversity and ecosystem risks arising from using guppies to control mosquitoes

    Rana W. El-Sabaawi; Therese C. Frauendorf; Piata S. Marques; Richard A. Mackenzie; Luisa R. Manna; Rosana Mazzoni; Dawn A. T. Phillip; Misha L. Warbanski; Eugenia Zandon

    2016-01-01

    Deploying mosquito predators such as the guppy (Poecilia reticulata) into bodies of water where mosquitoes breed is a common strategy for limiting the spread of disease-carrying mosquitoes. Here, we draw on studies from epidemiology, conservation, ecology and evolution to show that the evidence for the effectiveness of guppies in controlling...

  1. Perception and personal protective measures toward mosquito bites by communities in Jaffna District, northern Sri Lanka.

    Surendran, S N; Kajatheepan, A

    2007-06-01

    Mosquito-borne diseases are of public health importance in war-torn northern Sri Lanka. The severity of mosquito bites and attitudes of the public toward mosquito problems were investigated using a structured questionnaire among communities in 3 administrative divisions in Jaffna District. One hundred fifty-four households were interviewed during this study. Sixty-four percent of the respondents reported that the mosquito problem was severe in their localities. Fifty-two percent stated that mosquito-biting activity was severe in the evening (1500 h-1900 h), 41% at night (after 1900 h), and 7% throughout the day. Severity of mosquito menace was found to have no association with type of house construction. Seventy-seven percent were able to name at least 1 disease transmitted by mosquitoes. Statistical analysis showed no association between education level and public awareness on mosquito-borne diseases. Nearly 88% were able to identify at least a breeding source of mosquitoes and most of them practice measures to eliminate suitable environments for mosquito breeding. Ninety-six percent used personal protective measures against mosquito bites during some seasons or throughout the year. Mosquito coils were the most commonly used personal protective method followed by bed nets. The monthly expenditure for personal protective measures varied from US$0.19 (LKR 20) to US$3.40 (LKR 350).

  2. Fauna de mosquitos asociada con Aedes aegypti en Guaduas, Colombia

    Víctor Alberto Olano

    1993-06-01

    Full Text Available Durante un estudio sobre la ecología del Aedes aegypti llevado a cabo en el área urbana de Guaduas, Colombia, se hallaron un total de siete especies de mosquitos que compartían hábitats con esta especie. Los criaderos en los cuales se encontró un mayor número de mosquitos asociados con el Aedes aegypti fueron los tanques bajos (albercas. Larvas de Toxorhynchites spp. se encontraron en tanques elevados. Se discute la importancia de estos hallazgos con relación a los aspectos de ecología y control del Aedes aegypti.

  3. Malaria model with periodic mosquito birth and death rates.

    Dembele, Bassidy; Friedman, Avner; Yakubu, Abdul-Aziz

    2009-07-01

    In this paper, we introduce a model of malaria, a disease that involves a complex life cycle of parasites, requiring both human and mosquito hosts. The novelty of the model is the introduction of periodic coefficients into the system of one-dimensional equations, which account for the seasonal variations (wet and dry seasons) in the mosquito birth and death rates. We define a basic reproduction number R(0) that depends on the periodic coefficients and prove that if R(0)1 then the disease is endemic and may even be periodic.

  4. Emerging mosquito species in Germany-a synopsis after 6 years of mosquito monitoring (2011-2016).

    Kampen, Helge; Schuhbauer, Astrid; Walther, Doreen

    2017-12-01

    Globalisation and climate change are the main drivers of invasion of non-endemic regions by mosquitoes. Mass transportation of people, animals and goods facilitate accidental long-distance displacement while climate warming supports active spread and establishment of thermophilic species. In the framework of a mosquito-monitoring programme, eight non-indigenous culicid species have been registered in Germany since 2011, with four of them being more or less efficient vectors of disease agents and another four now considered established. The eight newly emerged species include Aedes albopictus, Ae. japonicus, Ae. aegypti, Ae. koreicus, Ae. berlandi, Ae. pulcritarsis, Anopheles petragnani and Culiseta longiareolata. We here review recent findings and at the same time present new findings of specimens of non-native mosquito species in Germany.

  5. Cultured skin microbiota attracts malaria mosquitoes

    Takken Willem

    2009-12-01

    Full Text Available Abstract Background Host-seeking of the African malaria mosquito, Anopheles gambiae sensu stricto, is guided by human odours. The precise nature of the odours, and the composition of attractive blends of volatiles, remains largely unknown. Skin microbiota plays an important role in the production of human body odours. It is hypothesized that host attractiveness and selection of An. gambiae is affected by the species composition, density, and metabolic activity of the skin microbiota. A study is presented in which the production and constituency of volatile organic compounds (VOCs by human skin microbiota is examined and the behavioural responses of An. gambiae to VOCs from skin microbiota are investigated. Methods Blood agar plates incubated with skin microbiota from human feet or with a reference strain of Staphylococcus epidermidis were tested for their attractiveness to An. gambiae in olfactometer bioassays and indoor trapping experiments. Entrained air collected from blood agar plates incubated with natural skin microbiota or with S. epidermidis were analysed using GC-MS. A synthetic blend of the compounds identified was tested for its attractiveness to An. gambiae. Behavioural data were analysed by a χ2-test and GLM. GC-MS results were analysed by fitting an exponential regression line to test the effect of the concentration of bacteria. Results More An. gambiae were caught with blood agar plates incubated with skin bacteria than with sterile blood agar plates, with a significant effect of incubation time and dilution of the skin microbiota. When bacteria from the feet of four other volunteers were tested, similar effects were found. Fourteen putative attractants were found in the headspace of the skin bacteria. A synthetic blend of 10 of these was attractive to An. gambiae. Conclusions The discovery that volatiles produced by human skin microorganisms in vitro mediate An. gambiae host-seeking behaviour creates new opportunities for the

  6. Abnormal levels of histone methylation in the retinas of diabetic rats are reversed by minocycline treatment

    Wang, Wenjun; Sidoli, Simone; Zhang, Wenquan

    2017-01-01

    67% of these marks had their relative abundance restored to non-diabetic levels after minocycline treatment. Mono-and di-methylation states of histone H4 lysine 20 (H4K20me1/me2), markers related to DNA damage response, were found to be up-regulated in the retinas of diabetic rats and restored......In this study we quantified the alterations of retinal histone post-translational modifications (PTMs) in diabetic rats using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach. Some diabetic rats were subsequently treated with minocycline, a tetracycline antibiotic, which has...... been shown to inhibit the diabetes-induced chronic inflammation in the retinas of rodents. We quantified 266 differentially modified histone peptides, including 48 out of 83 methylation marks with significantly different abundancein retinas of diabetic rats as compared to non-diabetic controls. About...

  7. Sobre la terapia génica para enfermedades de la retina.

    Fischer, M Dominik

    2017-07-11

    Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina. © 2017 S. Karger AG, Basel.

  8. Testbeam results of the first real-time embedded tracking system with artificial retina

    Neri, N., E-mail: nicola.neri@mi.infn.it; Abba, A.; Caponio, F.; Citterio, M.; Coelli, S.; Fu, J.; Merli, A.; Monti, M.; Petruzzo, M.

    2017-02-11

    We present the testbeam results of the first real-time embedded tracking system based on artificial retina algorithm. The tracking system prototype is capable of fast track reconstruction with a latency of the response below 1 μs and track parameter resolutions that are comparable with the offline results. The artificial retina algorithm was implemented in hardware in a custom data acquisition board based on commercial FPGA. The system was tested successfully using a 180 GeV/c proton beam at the CERN SPS with a maximum track rate of about 280 kHz. Online track parameters were found in good agreement with offline results and with the simulated response. - Highlights: • First real-time tracking system based on artificial retina algorithm tested on beam. • Fast track reconstruction within one microsecond latency and offline like quality. • Fast tracking algorithm implemented in commercial FPGAs.

  9. Ontogenetic expression of the Otx2 and Crx homeobox genes in the retina of the rat

    Rath, Martin F; Morin, Fabrice; Shi, Qiong

    2007-01-01

    . This confirmed the presence of Otx2 mRNA in both the embryonic retinal pigment epithelium and the developing neural retina. During development, the expression of Otx2 persists in the pigment epithelium, whereas Otx2 expression of the neural retina becomes progressively restricted to the outer nuclear layer......Otx2 and Crx are vertebrate orthologs of the orthodenticle family of homeobox genes, which are involved in retinal development. In this study, the temporal expression patterns of Otx2 and Crx in the rat retina during embryonic and postnatal stages of development were analyzed in detail...... and the outer part of the inner nuclear layer. Immunohistochemistry revealed that Otx2 protein is also present in cell bodies of the ganglion cell layer, which does not contain the Otx2 transcript, suggesting that Otx2 protein is synthesized in cell bodies of the bipolar neurons and then transported...

  10. Los mosquitos (Diptera: Culicidae y su importancia en Venezuela | The mosquitoes (Diptera: Culicidae And their importance in Venezuela

    Irma Fátima Agrela Da Silva

    2018-01-01

    Full Text Available Mosquitoes are responsible for the transmission of various diseases that affect the health of the Venezuelan population. The increase in the incidence of malaria and the emergence of diseases such as chikungunya and Zika make it necessary to implement control measures to reduce the impact of these diseases in Venezuela. To do this, it is essential to know the aspects related to their morphology, bioecology and the characteristics that make possible the participation of mosquitoes in the transmission of these diseases. The purpose of this review is to describe these aspects.

  11. Training and professional profile of retinologists in Spain: Retina 2 project, Report 4

    Pastor JC

    2011-04-01

    Full Text Available J Carlos Pastor1,3, Itziar Fernández2, Jimena Rojas1, Rosa Coco1, Maria R Sanabria1, Enrique Rodríguez-de la Rúa1,3, Diego Sánchez3, Carmen Valverde3, Anna Sala Puigdollers1,31University Institute of Applied Ophthalmobiology (IOBA, Retina Group, 2Ministry of Science and Innovation CIBER-BBN, Statistics Department, 3Clinic University Hospital, University of Valladolid, Valladolid, SpainBackground: Uniform postresidency systems to train medical specialists have not been developed in most European countries. Before developing a framework for such a system, we established the learning and professional profiles of Spanish ophthalmologists dedicated to medical retina and vitreoretina subspecialties.Methods: After identification of presumed subspecialists by experts from different autonomous regions, a self-administered questionnaire was mailed in 2006. A reminder was sent three weeks later. Postal mail was used. Nonresponder bias was determined.Results: Of 492 possible retina subspecialists, 261 replied to the questionnaires. While about 86% received specific retinal training, standardized fellowship programs were uncommon for both medical retina and vitreoretina (around 10%. Of the responders, 24.5% performed only medical retina, 11.8% vitreoretina, and 63.6% both. Most (60.5% practiced anterior segment surgery, and 78.7% declared skills in vitrectomy.Conclusion: We have developed a database of Spanish ophthalmologists dedicated to retinal pathologies and identified some characteristics of their professional profile. Although most of them have received specific retinal training, standardized mastership programs are still uncommon. These data will be useful in creating a standardized Retina Mastership, an important goal of the European Higher Education Area.Keywords: clinical activity, fellowship, mastership, professional profile, retinologist training

  12. Cell therapeutics to treat diseases of the retina

    Natarajan S

    2008-11-01

    Full Text Available Background: The adult Bone Marrow Stem Cells (BMSCs have distinct advantages over the other types of stem cells. They are multipotent, can be stored for upto 10 years and considered to be one of the best sources of hematopoietic and mesenchymal stem cells in an adult body. Genetically inherited diseases such as Retinitis Pigmentosa and Degenerative diseases such as Age Related Macular Degeneration remain unsolved as no definitive treatment is available to repair the damages caused to the RPE and Photoreceptors as of now. In this scenario, the technique of Bone Marrow aspiration & isolation of Mono Nucleated Cells (MNCs & intra-vitreal injection of a very small volume of MNCs in human retinal disorders has been standardized and is safe and feasible for human studies (Mohanty et al and autotransplantation of RPEs from periphery to affected area are underpractice(Coffey et al. In this study we report our research work on different approaches to the above diseases using cell therapeuticsStudy 1 Materials & methods: Ciliary Pigment Epithelium was harvested from donor eyes from Aditya Jyot Eye Hospital, Mumbai and was taken to and grown at NCRM lab. The cells were grown in the earlier reported methodology of Brenda et al (Science 2004. Results: The CPE derived Retinal stem cells grew well in the lab. However, the practical difficulties of harvesting the same in patients limited our further steps in this study. Study II:? Materials & methods: Cadaver eye RPE cells were harvested and grown using polymer scaffolds after transporting them over 6 to 12 Hrs. The RPEs were grown on conventional methods and in polymer scaffolds and were subjected to RT-PCR. Results: Human RPEs were able to grow without amniotic membrane and the same was proven by RT-PCR. This would make it possible for the peripheral RPEs taken from patients to be stored and later expanded and used for replacing the diseased cells of the central portion of the retina in future, without having

  13. Peripheral Avascular Retina in a Term Male Neonate With Microvillus Inclusion Disease and Pancreatic Insufficiency.

    Paulus, Yannis M; Alcorn, Deborah M; Gaynon, Michael; Moshfeghi, Darius M

    2015-05-01

    The authors present the first case of peripheral avascular retina in a term male neonate with pancreatic exocrine insufficiency, atypical microvillus inclusion disease, flat tympanograms, and recurrent urinary tract infections. Clinical examination showed avascular peripheral retina to posterior zone II temporally, with a flat stage 1-like demarcation line, and no plus disease. Genetic testing results were normal. The patient developed peripheral neovascularization and underwent panretinal photocoagulation. This case likely represents mild Norrie disease, familial exudative vitreoretinopathy, or incontinentia pigmenti due to a Wnt signaling abnormality. While these conditions are usually more severe, a variable spectrum of Wnt abnormalities exists throughout the body. Copyright 2015, SLACK Incorporated.

  14. Msx1 is expressed in retina endothelial cells at artery branching sites

    Miguel Lopes; Olivier Goupille; Cécile Saint Cloment; Benoît Robert

    2012-01-01

    Summary Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1lacZ is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2lacZ is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the ret...

  15. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with multimodal photoacoustic ophthalmoscopy

    Zhang, Xiangyang; Zhang, Hao F.; Zhou, Lixiang; Jiao, Shuliang

    2012-02-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective vs. exacerbate) in the RPE in the aging process. We successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  16. Photonic crystal light collectors in fish retina improve vision in turbid water.

    Kreysing, Moritz; Pusch, Roland; Haverkate, Dorothee; Landsberger, Meik; Engelmann, Jacob; Ruiter, Janina; Mora-Ferrer, Carlos; Ulbricht, Elke; Grosche, Jens; Franze, Kristian; Streif, Stefan; Schumacher, Sarah; Makarov, Felix; Kacza, Johannes; Guck, Jochen; Wolburg, Hartwig; Bowmaker, James K; von der Emde, Gerhard; Schuster, Stefan; Wagner, Hans-Joachim; Reichenbach, Andreas; Francke, Mike

    2012-06-29

    Despite their diversity, vertebrate retinae are specialized to maximize either photon catch or visual acuity. Here, we describe a functional type that is optimized for neither purpose. In the retina of the elephantnose fish (Gnathonemus petersii), cone photoreceptors are grouped together within reflecting, photonic crystal-lined cups acting as macroreceptors, but rod photoreceptors are positioned behind these reflectors. This unusual arrangement matches rod and cone sensitivity for detecting color-mixed stimuli, whereas the photoreceptor grouping renders the fish insensitive to spatial noise; together, this enables more reliable flight reactions in the fish's dim and turbid habitat as compared with fish lacking this retinal specialization.

  17. Diagnostic classification of retinal degenerative diseases São Paulo and Vale Retina groups

    Unonius, Nichard; Farah, Michel Eid; Sallum, Juliana M. Ferraz

    2003-01-01

    OBJETIVO:Organizar um banco de dados regional de todos os indivíduos portadores de doenças degenerativas da retina, com o objetivo de classificar cada paciente de acordo com o tipo de distrofia e padrão de herança. MÉTODOS: Durante o encontro do Grupo Retina São Paulo no dia 5 de maio de 2001, duzentas e quarenta e três pessoas foram registradas, sendo que parte forneceu dados de antecedentes oculares, pessoais e familiares e árvore genealógica. Noventa e três pacientes foram questionados qua...

  18. Modelación y simulación de la retina humana

    Andrés Castaño; Camilo Montenegro; Carlos Molina; Sergio Mejía

    2001-01-01

    Las enfermedades de la retina causan pérdida de la visión de varios
    grados de severidad; las causas son múltiples y en la mayoría de los casos irreversibles. En los últimos años se ha venido desarrollando investigación en el campo de la visión artificial y la visión por computador, alrededor de todo el mundo. Nuestro proyecto pretende desarrollar un modelo matemático de la retina, implementar la solución numérica en MATLAB™ y posteriormente construir un dispositivo electró...

  19. Cellular disturbance in the rats retina after irradiation and metabolic errors during the postnatal period

    Lierse, W.; Franke, H.D.

    1982-01-01

    During the first five days of the postnatal period the retina has been vulnerable following administration of DNA blocking drugs and irradiation with conventional X-rays and fast neutrons. During this period the disturbance of lamination accompanied with pycnosis of neurons and neuroblasts has been the important morphologic reaction. During the same phase metabolic errors, like experimental phenylketonuria, have produced a swelling of photoreceptor cells and pigmentepithelium cells. The other neurons of the retina were pycnotic. Structural alterations like rosettes persisted during the rest of life. The relative minor error during the first phase of rats life may result in a persistent disease. (orig.)

  20. Nutritional manipulation of primate retinas, III: Effects of lutein or zeaxanthin supplementation on adipose tissue and retina of xanthophyll-free monkeys.

    Johnson, Elizabeth J; Neuringer, Martha; Russell, Robert M; Schalch, Wolfgang; Snodderly, D Max

    2005-02-01

    Macular pigment (MP) is composed of the xanthophylls lutein (L) and zeaxanthin (Z) and may help to prevent age-related macular degeneration or retard its progression. In this study the effects of L or Z supplementation on carotenoid levels was examined in serum, adipose tissue, and retina in rhesus monkeys with no previous intake of xanthophylls. From birth to 7 to 16 years of age, 18 rhesus monkeys were fed semipurified diets containing all essential nutrients but no xanthophylls. Six were supplemented with pure L and 6 with pure Z at 3.9 micromol/kg per day for 24 to 101 weeks. At baseline and at 4- to 12-week intervals, carotenoids in adipose tissue were measured by HPLC. At study completion, carotenoids in serum and retina (central 4 mm, 8-mm annulus, and the periphery) were determined. Results were compared with data from control monkeys fed a standard laboratory diet. Monkeys fed xanthophyll-free diets had no L or Z in serum or tissues. After L or Z supplementation, serum and adipose tissue concentrations significantly increased in the supplemented groups. Both L and 3R,3'S-Z (RSZ or meso-Z, not present in the diet) were incorporated into retinas of monkeys supplemented with L, with RSZ present only in the macula (central 4 mm). All-trans Z, but no RSZ, accumulated in retinas of monkeys supplemented with Z. L is the precursor of RSZ, a major component of macular pigment. Xanthophyll-free monkeys can accumulate retinal xanthophylls and provide a valuable model for examining their uptake and conversion.

  1. Mechanisms of Plasmodium-Enhanced Attraction of Mosquito Vectors

    Busula, A.O.; Verhulst, N.O.; Bousema, J.T.; Takken, W.; Boer, J.G. de

    2017-01-01

    Evidence is accumulating that Plasmodium-infected vertebrates are more attractive to mosquitoes than noninfected hosts, particularly when high levels of gametocytes are present. Changes in host odour have been suggested as a likely target for parasite manipulation because olfactory cues are crucial

  2. Attraction of Mosquitoes to Diethyl Methylbenzamide and Ethyl Hexanediol

    1990-09-01

    tant to the biting midges Culicoides pulicaris that 8% ethyl acetate was attractant to the Linn. and Culicoides puncticoUis Becker (Cera- vinegar fly...Drosoph- finding by mosquitoes (Diptera: Culcidae): a review. ila melanogaster Meigen to the products of ferment - Bull. Entomol. Res. 70:525-532. ing banana

  3. Crab Hole Mosquito Blues—The Story

    This podcast reports on a humorous song that takes a look at a very serious human and equine disease. Written and performed by the MARU Health Angels Band, Bill Dietz, director of the Division of Nutrition, Physical Activity and Obesity at CDC, talks about the song, "Crab Hole Mosquito Blues", and the history behind it.

  4. assessment of mosquito diversity and evaluation of impact of house

    Dr Osondu

    Malaria, a disease that has increasingly been ravaging human population still has no sustainable remedy. Therefore, mosquito diversity and impact of house treatment with dichlorodiphenyltrichloroethane (DDT) on their population were investigated by the use of miniature. Centre for Disease Control light trap (model 512) ...

  5. Información general sobre los mosquitos

    Una consecuencia más importante de algunas picaduras de mosquitos es la trasmisión de ciertas enfermedades graves como el paludismo, la fiebre del dengue y varias formas de encefalitis, que incluyen el virus del Nilo occidental.

  6. Susceptibility of Adult Mosquitoes to Insecticides in Aqueous Sucrose Baits

    2011-06-01

    Lee, and A.H. Azahari. 2005. Adult and larval insecticide susceptibility status of Culex quinquefasciatus (Say) mosquitoes in Kuala Lumpur Malaysia ...Trop. Biomed. 22: 63-68. Nayar, J.K. and D.M. Sauerman, Jr. 1971. The effects of diet on life-span, fecundity and flight potential of Aedes

  7. Insecticide mixtures for mosquito net impregnation against malaria vectors

    Corbel V.

    2002-09-01

    Full Text Available Insecticides belonging to the pyrethroid family are the only compounds currently available for the treatment of mosquito nets. Unfortunately, some malaria vector species have developed resistance to pyrethroids and the lack of alternative chemical categories is a great concern. One strategy for resistance management would be to treat mosquito nets with a mixture associating two insecticides having different modes of action. This study presents the results obtained with insecticide mixtures containing several proportions of bifenthrin (a pyrethroid insecticide and carbosulfan (a carbamate insecticide. The mixtures were sprayed on mosquito net samples and their efficacy were tested against a susceptible strain of Anopheles gambiae, the major malaria vector in Africa. A significant synergism was observed with a mixture containing 25 mg/m2 of bifenthrin (half the recommended dosage for treated nets and 6.25 mg/m2 of carbosulfan (about 2 % of the recommended dosage. The observed mortality was significantly more than expected in the absence of any interaction (80 % vs 41 % and the knock-down effect was maintained, providing an effective barrier against susceptible mosquitoes.

  8. Spatial distribution and habitat characterisation of mosquito species ...

    Background: Infections with mosquito-borne parasites are common in human populations inhabiting tropical regions of the world. Malaria is endemic along Kenyan Lake Victoria basin and its vectors are fresh water breeders. However, much less is known about the current spatial distribution and habitat characterisation of ...

  9. Mosquito-larvicidal efficacy of the extract of Musca domestica ...

    The intolerably high burdens of mosquito-borne diseases will be reduced sustainably through the development of integral eco-friendly alternative insecticides of natural products origin. The need to broaden the global search for such insecticidal lead-agents, especially , those that will be less vulnerable to resistance, was ...

  10. High proportion of mosquito vectors in Zika forest, Uganda, feeding ...

    There is a steady increase in the contact between humans and wildlife, brought about by encroachment, destruction of natural forests, climatic and environmental changes. Mosquitoes get exposed to hosts and pathogens; creating possibilities for new disease patterns. Therefore, the identification of blood-meal sources is ...

  11. Impact of road construction on malaria incidence and mosquito ...

    This study evaluated the impact of road construction on the incidence of malaria cases reported at Primary Health Centres (PHCs) as well as vector abundance in Abeokuta South and North Local Government Areas (LGAs) of Ogun State. Mosquito larvae were collected from randomly selected four road construction sites ...

  12. Biological control agent for mosquito larvae: Review on the killifish ...

    This review attempts to give an account on the recent advances on the killifish Aphanius dispar dispar as a biological control agent for mosquito larvae. Thirty six (36) articles of literature (scientific papers, technical and workshop reports) on this subject covering the period between 1980 and 2009 were reviewed.

  13. Knowledge, attitudes and practices regarding malaria and mosquito ...

    To improve control measures against malaria, Tanzania has increased the distribution of free and subsidized insecticide-treated mosquito nets (ITNs) to pregnant women. However, data on knowledge, attitudes and practices of these women regarding malaria are scarce. This study was carried out to describe knowledge, ...

  14. Insecticide resistance and glutathione S-transferases in mosquitoes ...

    Mosquito glutathione S-transferases (GSTs) have received considerable attention in the last 20 years because of their role in insecticide metabolism producing resistance. Many different compounds, including toxic xenobiotics and reactive products of intracellular processes such as lipid peroxidation, act as GST substrates.

  15. Community awareness about malaria, its treatment and mosquito ...

    Background: Despite the rapid expansion of malaria into highland areas of Ethiopia and the movement of malaria inexperienced people to endemic areas, there is no enough information about how highland communities perceive malaria. Objective: To assess communities' awareness of malaria and its mosquito vector in ...

  16. Analysis of a Malaria Model with Mosquito-Dependent Transmission ...

    In this paper, we discuss an ordinary differential equation mathematical model for the spread of malaria in human and mosquito population. We suppose the human population to act as a reservoir. Both the species follow a logistic population model. The transmission coefficient or the interaction coefficient of humans is ...

  17. Species\\' identification of Anopheles and Culex mosquitoes and its ...

    Indoor and outdoor bites' collections of gravid Anopheles and Culex mosquitoes were made with plastic aspirator from residential areas within Jimeta-Yola metropolis for three years (between March and May; August and October 2003 to 2005). They were identified using standard morphological keys and polymerase chain ...

  18. Help Control Mosquitoes that Spread Dengue, Chikungunya, and Zika Viruses

    ... than an adult mosquito. If you have a septic tank, follow these steps: • • Repair cracks or gaps. • • Cover ... Wear long-sleeved shirts and long pants. Keep septic tanks sealed. Install or repair window & door screens. August ...

  19. Acoustic control of mosquito larvae in artificial drinking water containers

    Acoustic larvicide devices are part of an emerging technology that provides a non-chemical and non-biological means to reduce larval populations of key medically important mosquito species such as Aedes aegypti in containers or catchments of water. These devices could benefit integrated vector manag...

  20. Malaria-induced changes in host odors enhance mosquito attraction.

    De Moraes, Consuelo M; Stanczyk, Nina M; Betz, Heike S; Pulido, Hannier; Sim, Derek G; Read, Andrew F; Mescher, Mark C

    2014-07-29

    Vector-borne pathogens may alter traits of their primary hosts in ways that influence the frequency and nature of interactions between hosts and vectors. Previous work has reported enhanced mosquito attraction to host organisms infected with malaria parasites but did not address the mechanisms underlying such effects. Here we document malaria-induced changes in the odor profiles of infected mice (relative to healthy individuals) over the course of infection, as well as effects on the attractiveness of infected hosts to mosquito vectors. We observed enhanced mosquito attraction to infected mice during a key period after the subsidence of acute malaria symptoms, but during which mice remained highly infectious. This attraction corresponded to an overall elevation in the volatile emissions of infected mice observed during this period. Furthermore, data analyses--using discriminant analysis of principal components and random forest approaches--revealed clear differences in the composition of the volatile blends of infected and healthy individuals. Experimental manipulation of individual compounds that exhibited altered emission levels during the period when differential vector attraction was observed also elicited enhanced mosquito attraction, indicating that compounds being influenced by malaria infection status also mediate vector host-seeking behavior. These findings provide important insights into the cues that mediate vector attraction to hosts infected with transmissible stages of malaria parasites, as well as documenting characteristic changes in the odors of infected individuals that may have potential value as diagnostic biomarkers of infection.

  1. Usutu Virus RNA in Mosquitoes, Israel, 2014-2015.

    Mannasse, Batya; Mendelson, Ella; Orshan, Laor; Mor, Orna; Shalom, Uri; Yeger, Tamar; Lustig, Yaniv

    2017-10-01

    We identified Usutu virus (USUV) RNA in 6 pools of mosquitoes trapped in northern Israel during 2014-2015. These Israeli strains were most similar to strains identified in Senegal and Germany, which further elucidates common ancestry and evolutionary dynamics of USUV. Our findings suggest that human infection with USUV might occur in Israel.

  2. Determination of toxic effects of commercial and local mosquito ...

    Elevated levels of alanine aminotransferase were seen with statistical significance at P < 0.05 between the group exposed to rice husk and the control and also between the rice husk and mosquito coil groups respectively. The results showed increased levels of alanine aminotransferase which could indicate acute liver ...

  3. Risk Factors for Mosquito House Entry in the Lao PDR

    Hiscox, A.F.; Khammanithong, P.; Kaul, S.; Sananikhom, P.; Luthi, R.; Hill, N.; Brey, P.T.; Lindsay, S.W.

    2013-01-01

    Background Construction of the Nam Theun 2 hydroelectric project and flooding of a 450 km2 area of mountain plateau in south-central Lao PDR resulted in the resettlement of 6,300 people to newly built homes. We examined whether new houses would have altered risk of house entry by mosquitoes compared

  4. Mosquito repellent activity of piper guineense and xylopia ...

    The activity of eucalyptus oil (positive control), a commercial repellent, at 30% was only able to protect for 2h. Both oils used could be applied as repellents where protection from mosquito bite is sought for, over a short period of time. Keywords: Piper guineense, Xylopia aethiopica, volatile oils, Aedes aegypti, repellency

  5. Factors Influencing the Usage of Insecticide Treated Mosquito Nets ...

    Purpose: Malaria in Sudan is a leading cause of morbidity and mortality. ... treated mosquito nets (ITNs) for prevention of malaria among pregnant women. ... on malaria causes, 103 (99%) had good knowledge on malaria complications and ... and accessibility to ITNs were significantly associated with current usage of ITNs.

  6. USDA Mosquito Control Product Research for the US Military

    New techniques that were developed at the USDA to protect deployed military troops from the threat of vector-borne diseases and are also applicable for use by civilian mosquito control program use are described. Techniques to be illustrated include: (1) novel military personal protection methods, (2...

  7. The use of sterilized mosquito nets for hernioplasty

    Sørensen, C G; Rosenberg, J

    2012-01-01

    Hernia repair is among the most frequent surgeries performed. Surgeons prefer the tension-free mesh repair, but in large parts of the world, commercial meshes are unavailable or unaffordable. Consequently, surgeons have been experimenting with insertion of inexpensive non-commercial meshes, the m......, the most common being a non-impregnated, sterilized mosquito net....

  8. Rift Valley fever potential mosquito vectors and their infection status ...

    important entomological features for the identification of potential high risk areas for RVF occurrence, which can provide guidance in the design of appropriate prevention and control measures. The findings of this study have shown that the abundance and diversity of potential. RVF mosquito vectors vary between the study ...

  9. A Statewide Survey for Container-Breeding Mosquitoes in Mississippi.

    Goddard, Jerome; Moraru, Gail M; Mcinnis, Sarah J; Portugal, J Santos; Yee, Donald A; Deerman, J Hunter; Varnado, Wendy C

    2017-09-01

    Container-breeding mosquitoes are important in public health due to outbreaks of Zika, chikungunya, and dengue viruses. This paper documents the distribution of container-breeding mosquito species in Mississippi, with special emphasis on the genus Aedes. Five sites in each of the 82 Mississippi counties were sampled monthly between May 1 and August 31, 2016, and 50,109 mosquitoes in 14 species were collected. The most prevalent and widely distributed species found was Ae. albopictus, being found in all 82 counties, especially during July. A recent invasive, Ae. japonicus, seems to be spreading rapidly in Mississippi since first being discovered in the state in 2011. The most abundant Culex species collected were Cx. quinquefasciatus (found statewide), Cx. salinarius (almost exclusively in the southern portion of the state), and Cx. restuans (mostly central and southern Mississippi). Another relatively recent invasive species, Cx. coronator, was found in 20 counties, predominantly in the southern one-third of the state during late summer. Co-occurrence data of mosquito species found in the artificial containers were also documented and analyzed. Lastly, even though we sampled extensively in 410 sites across Mississippi, no larval Ae. aegypti were found. These data represent the first modern statewide survey of container species in Mississippi, and as such, allows for better public health readiness for emerging diseases and design of more effective vector control programs.

  10. Detecting multiple DNA human profile from a mosquito blood meal.

    Rabêlo, K C N; Albuquerque, C M R; Tavares, V B; Santos, S M; Souza, C A; Oliveira, T C; Moura, R R; Brandão, L A C; Crovella, S

    2016-08-26

    Criminal traces commonly found at crime scenes may present mixtures from two or more individuals. The scene of the crime is important for the collection of various types of traces in order to find the perpetrator of the crime. Thus, we propose that hematophagous mosquitoes found at crime scenes can be used to perform genetic testing of human blood and aid in suspect investigation. The aim of the study was to obtain a single Aedes aegypti mosquito profile from a human DNA mixture containing genetic materials of four individuals. We also determined the effect of blood acquisition time by setting time intervals of 24, 48, and 72 h after the blood meal. STR loci and amelogenin were analyzed, and the results showed that human DNA profiles could be obtained from hematophagous mosquitos at 24 h following the blood meal. It is possible that hematophagous mosquitoes can be used as biological remains at the scene of the crime, and can be used to detect human DNA profiles of up to four individuals.

  11. Highly evolvable malaria vectors : The genomes of 16 Anopheles mosquitoes

    Neafsey, D. E.; Waterhouse, R. M.; Abai, M. R.; Aganezov, S. S.; Alekseyev, M. A.; Allen, J. E.; Amon, J.; Arca, B.; Arensburger, P.; Artemov, G.; Assour, L. A.; Basseri, H.; Berlin, A.; Birren, B. W.; Blandin, S. A.; Brockman, A. I.; Burkot, T. R.; Burt, A.; Chan, C. S.; Chauve, C.; Chiu, J. C.; Christensen, M.; Costantini, C.; Davidson, V. L. M.; Deligianni, E.; Dottorini, T.; Dritsou, V.; Gabriel, S. B.; Guelbeogo, W. M.; Hall, A. B.; Han, M. V.; Hlaing, T.; Hughes, D. S. T.; Jenkins, A. M.; Jiang, X.; Jungreis, I.; Kakani, E. G.; Kamali, M.; Kemppainen, P.; Kennedy, R. C.; Kirmitzoglou, I. K.; Koekemoer, L. L.; Laban, N.; Langridge, N.; Lawniczak, M. K. N.; Lirakis, M.; Lobo, N. F.; Lowy, E.; Maccallum, R. M.; Mao, C.; Maslen, G.; Mbogo, C.; Mccarthy, J.; Michel, K.; Mitchell, S. N.; Moore, W.; Murphy, K. A.; Naumenko, A. N.; Nolan, T.; Novoa, E. M.; O'loughlin, S.; Oringanje, C.; Oshaghi, M. A.; Pakpour, N.; Papathanos, P. A.; Peery, A. N.; Povelones, M.; Prakash, A.; Price, D. P.; Rajaraman, A.; Reimer, L. J.; Rinker, D. C.; Rokas, A.; Russell, T. L.; Sagnon, N.; Sharakhova, M. V.; Shea, T.; Simao, F. A.; Simard, F.; Slotman, M. A.; Somboon, P.; Stegniy, V.; Struchiner, C. J.; Thomas, G. W. C.; Tojo, M.; Topalis, P.; Tubio, J. M. C.; Unger, M. F.; Vontas, J.; Walton, C.; Wilding, C. S.; Willis, J. H.; Wu, Y.-c.; Yan, G.; Zdobnov, E. M.; Zhou, X.; Catteruccia, F.; Christophides, G. K.; Collins, F. H.; Cornman, R. S.; Crisanti, A.; Donnelly, M. J.; Emrich, S. J.; Fontaine, M. C.; Gelbart, W.; Hahn, M. W.; Hansen, I. A.; Howell, P. I.; Kafatos, F. C.; Kellis, M.; Lawson, D.; Louis, C.; Luckhart, S.; Muskavitch, M. A. T.; Ribeiro, J. M.; Riehle, M. A.; Sharakhov, I. V.; Tu, Z.; Zwiebel, L. J.; Besansky, N. J.

    2015-01-01

    Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16

  12. [Mosquito complex (Diptera, Culicidae) in a West Nile fever focus in the Volgograd Region. II. Host-feeding patterns of mosquitoes in different habitats].

    Platonova, O V; Fedorova, M V; Lopatina, Iu V; Bezzhonova, O V; Bulgakova, T V; Platonov, A E

    2007-01-01

    Host preference of the mosquitoes collected in the urban and rural habitats of Volgograd and its suburbs was studied by the precipitation reaction test. Human and avian blood was detected in Cx. pipiens, Cx. modestus, Ae. vexans, Ae. behningi, Ae. caspius, Ae. sticticus, and females of the Anopheles maculipennis. The proportion of the mosquitoes fed on birds was similar in the urban and rural biotopes whereas that of the mosquitoes feeding on humans was significantly higher in Volgograd than in its environs. The increase in the number of human blood-fed mosquitoes in the city resulted mainly from the females collected in its multi-storied buildings.

  13. Aparelho de sucção tipo aspirador para captura de mosquitos A "vacuum-cleaner" type of suction apparatus for the collection of mosquitoes

    Délsio Natal

    1984-10-01

    Full Text Available É feita a descrição de aparelho portátil de sucção tipo aspirador, para captura de mosquitos Culicidae. São sugeridas adaptações para coletas em diferentes situações. São feitos comentários sobre sua aplicação em pesquisa de mosquitos.A portable suction apparatus, which functions like a vacuum cleaner used for the collection of Culicidae mosquitoes is described. Adaptations for collecting in differents situations are suggested and some comments about its application in mosquitoes surveys are made.

  14. Mosquito population dynamics during the construction of Three Gorges Dam in Yangtze River, China.

    Guo, Yuhong; Lai, ShengJie; Zhang, Jing; Liu, Qiyong; Zhang, Huaiqing; Ren, Zhoupeng; Mao, Deqiang; Luo, Chao; He, Yuanyuan; Wu, Haixia; Li, Guichang; Ren, Dongsheng; Liu, Xiaobo; Chang, Zhaorui

    2018-06-01

    Mosquitoes are responsible for spreading many diseases and their populations are susceptible to environmental changes. The ecosystems in the Three Gorges Region were probably altered because of changes to the environment during the construction of the Three Gorges Dam (TGD), the world's largest hydroelectric dam by generating capacity. We selected three sites at which to monitor the mosquitoes from 1997 to 2009. We captured adult mosquitoes with battery-powered aspirators fortnightly between May and September of each year in dwellings and sheds. We identified the mosquito species, and examined changes in the species density during the TGD construction. We monitored changes in the species and density of mosquitoes in this area for 13 years during the TGD construction and collected information that could be used to support the control and prevention of mosquito-borne infections. We found that the mosquito species composition around the residential areas remained the same, and the density changed gradually during the TGD construction. The changes in the populations tended to be consistent over the years, and the densities were highest in July, and were between 3 and 5 times greater in the sheds than in the dwellings. The mosquito species and populations remained stable during the construction of the TGD. The mosquito density may have increased as the reservoir filled, and may have decreased during the clean-up work. Clean-up work may be an effective way to control mosquitoes and prevent mosquito-borne diseases. Copyright © 2018. Published by Elsevier B.V.

  15. Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence

    Bialosuknia, Sean M.; Zink, Steven D.; Brecher, Matthew; Ehrbar, Dylan J.; Morrissette, Madeline N.; Kramer, Laura D.

    2017-01-01

    In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1–7.5 log10 PFU/mL; minimum infective dose was 4.2 log10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas. PMID:28430564

  16. Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence.

    Ciota, Alexander T; Bialosuknia, Sean M; Zink, Steven D; Brecher, Matthew; Ehrbar, Dylan J; Morrissette, Madeline N; Kramer, Laura D

    2017-07-01

    In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1-7.5 log 10 PFU/mL; minimum infective dose was 4.2 log 10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas.

  17. Altered vector competence in an experimental mosquito-mouse transmission model of Zika infection.

    Ryuta Uraki

    2018-03-01

    Full Text Available Few animal models of Zika virus (ZIKV infection have incorporated arthropod-borne transmission. Here, we establish an Aedes aegypti mosquito model of ZIKV infection of mice, and demonstrate altered vector competency among three strains, (Orlando, ORL, Ho Chi Minh, HCM, and Patilas, PAT. All strains acquired ZIKV in their midguts after a blood meal from infected mice, but ZIKV transmission only occurred in mice fed upon by HCM, and to a lesser extent PAT, but not ORL, mosquitoes. This defect in transmission from ORL or PAT mosquitoes was overcome by intrathoracic injection of ZIKV into mosquito. Genetic analysis revealed significant diversity among these strains, suggesting a genetic basis for differences in ability for mosquito strains to transmit ZIKV. The intrathoracic injection mosquito-mouse transmission model is critical to understanding the influence of mosquitoes on ZIKV transmission, infectivity and pathogenesis in the vertebrate host, and represents a natural transmission route for testing vaccines and therapeutics.

  18. Use of Nicotiana tabacum L extract for anti-Aedes Aegypti mosquito paint

    Sandralintang, Trisiana Chrysanthi; Fauzantoro, Ahmad; Hermansyah, Heri; Jufri, Mahdi; Gozan, Misri

    2018-02-01

    This study intended to formulate mosquito repellent paints based tobacco leaf extracts-free pyrethroid substance which is safe for users. The active substance which was added to the paint as a mosquito repellent was an extract of tobacco leaves. The result of Anti-mosquito paint formulation produced was according to the Indonesia National Standard (SNI). The results of anti-Aedes Aegypti mosquito paint effectiveness test showed that 5% concentration of tobacco extract could kill half of the mosquito population (LC50) for 2 hours, the concentration of tobacco extract between 3-5% killed half the mosquito population (LC50) during 4 hours, while 1-3% and 0-1% concentration of tobacco extract killed half the mosquito population (LC50) for 6 and 24 hours, respectively.

  19. Mosquito (Diptera: Culicidae) Habitat Surveillance by Android Mobile Devices in Guangzhou, China.

    Wu, Tai-Ping; Tian, Jun-Hua; Xue, Rui-De; Fang, Yi-Liang; Zheng, Ai-Hua

    2016-12-17

    In 2014, Guangzhou City, South China, suffered from its worst outbreak of dengue fever in decades. Larval mosquito habitat surveillance was carried out by using android mobile devices in four study sites in May 2015. The habitats with larval mosquitoes were recorded as photo waypoints in OruxMaps or in videos. The total number of potential mosquito habitats was 342, of which 166 (49%) were found to have mosquito larvae or pupae. Small containers were the most abundant potential habitats, accounting for 26% of the total number. More mosquito larvae and pupae, were found in small containers than in other objects holding water, for example, potted or hydroponic plants ( p Android mobile devices are a convenient and useful tool for surveillance of mosquito habitats, and the enhancement of source reduction may benefit the prevention and control of dengue vector mosquitoes.

  20. Degenerações periféricas da retina do olho míope X LASIK

    Nassaralla Jr. João J.

    2004-01-01

    Full Text Available O objetivo deste artigo é apresentar as degenerações periféricas mais comuns na retina dos olhos míopes, discutindo aquelas que oferecem maiores riscos para o descolamento regmatogênico da retina, seu relacionamento com a cirurgia de LASIK e a indicação para o tratamento profilático.

  1. Limitation of using synthetic human odours to test mosquito repellents

    Mbeyela Edgar

    2009-07-01

    Full Text Available Abstract Background Gold-standard tests of mosquito repellents involve exposing human volunteers to host-seeking mosquitoes, to assess the protective efficacy of the repellents. These techniques are not exposure-free and cannot be performed prior to toxicological evaluation. It is postulated that synthetic lures could provide a useful assay that mimics in-vivo conditions for use in high-throughput screening for mosquito repellents. Methods This paper reports on a semi-field evaluation of repellents using a synthetic blend of human derived attractants for the malaria vector, Anopheles gambiae sensu stricto Different concentrations of known repellents, N, N diethyl-3-methylbenzamide (deet and Para-methane-3, 8, diol (PMD were added into traps baited with the synthetic blend, and resulting changes in mosquito catches were measured. Results All test concentrations of deet (0.001% to 100% reduced the attractiveness of the synthetic blend. However, PMD was repellent only at 0.25%. Above this concentration, it significantly increased the attractiveness of the blend. There was no relationship between the repellent concentrations and the change in mosquito catches when either deet (r2 = 0.033, P = 0.302 or PMD (r2 = 0.020, P = 0.578 was used. Conclusion It is concluded that while some repellents may reduce the attractiveness of synthetic human odours, others may instead increase their attractiveness. Such inconsistencies indicate that even though the synthetic attractants may provide exposure-free and consistent test media for repellents, careful selection and multiple-repellent tests are necessary to ascertain their suitability for use in repellent screening. The synthetic odour blend tested here is not yet sufficiently refined to serve as replacement for humans in repellent testing, but may be developed further and evaluated in different formats for exposure free repellent testing purposes.

  2. Plasmodium Cysteine Repeat Modular Proteins 3 and 4 are essential for malaria parasite transmission from the mosquito to the host

    Mota Maria M

    2011-03-01

    Full Text Available Abstract Background The Plasmodium Cysteine Repeat Modular Proteins (PCRMP are a family of four conserved proteins of malaria parasites, that contain a number of motifs implicated in host-parasite interactions. Analysis of mutants of the rodent parasite Plasmodium berghei lacking expression of PCRMP1 or 2 showed that these proteins are essential for targeting of P. berghei sporozoites to the mosquito salivary gland and, hence, for transmission from the mosquito to the mouse. Methods In this work, the role of the remaining PCRMP family members, PCRMP3 and 4, has been investigated throughout the Plasmodium life cycle by generation and analysis of P. berghei gene deletion mutants, Δpcrmp3 and Δpcrmp4. The role of PCRMP members during the transmission and hepatic stages of the Plasmodium lifecycle has been evaluated by light- and electron microscopy and by analysis of liver stage development in HEPG2 cells in vitro and by infecting mice with mutant sporozoites. In addition, mice were immunized with live Δpcrmp3 and Δpcrmp4 sporozoites to evaluate their immunization potential as a genetically-attenuated parasite-based vaccine. Results Disruption of pcrmp3 and pcrmp4 in P. berghei revealed that they are also essential for transmission of the parasite through the mosquito vector, although acting in a distinct way to pbcrmp1 and 2. Mutants lacking expression of PCRMP3 or PCRMP4 show normal blood stage development and oocyst formation in the mosquito and develop into morphologically normal sporozoites, but these have a defect in egress from oocysts and do not enter the salivary glands. Sporozoites extracted from oocysts perform gliding motility and invade and infect hepatocytes but do not undergo further development and proliferation. Furthermore, the study shows that immunization with Δcrmp3 and Δcrmp4 sporozoites does not confer protective immunity upon subsequent challenge. Conclusions PCRMP3 and 4 play multiple roles during the Plasmodium life

  3. Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector.

    Crawford, Jacob E; Alves, Joel M; Palmer, William J; Day, Jonathan P; Sylla, Massamba; Ramasamy, Ranjan; Surendran, Sinnathamby N; Black, William C; Pain, Arnab; Jiggins, Francis M

    2017-02-28

    The mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans. To understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants. We conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for disease transmission.

  4. Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector

    Crawford, Jacob E.

    2017-02-20

    BackgroundThe mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans.ResultsTo understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants.ConclusionsWe conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for

  5. Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)

    Erickson, R A; Presley, S M; Cox, S B; Hayhoe, K; Allen, L J S; Long, K R

    2012-01-01

    Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems. (letter)

  6. Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)

    Erickson, R. A.; Hayhoe, K.; Presley, S. M.; Allen, L. J. S.; Long, K. R.; Cox, S. B.

    2012-09-01

    Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems.

  7. Distribution of mosquitoes and mosquito-borne arboviruses in Yunnan Province near the China-Myanmar-Laos border.

    Wang, Jinglin; Zhang, Hailin; Sun, Xiaohong; Fu, Shihong; Wang, Huanqin; Feng, Yun; Wang, Huanyu; Tang, Qing; Liang, Guo-Dong

    2011-05-01

    Economic development and increased tourism in the southern region of Yunnan Province in China, adjacent to several countries in Southeast Asia, has increased the likelihood of import and export of vectors and vector-borne diseases. We report the results of surveillance of mosquitoes and mosquito-borne arboviruses along the border of China-Myanmar-Laos in 2005 and 2006, and information associating several arboviruses with infections and possibly disease in local human populations. Seventeen mosquito species representing four genera were obtained, and 14 strains of mosquito-borne viruses representing six viruses in five genera were isolated from Culex tritaeniorhynchus. In addition, IgM against Japanese encephalitis virus, Sindbis virus, Yunnan orbivirus and novel Banna virus was detected in acute-phase serum samples obtained from hospitalized patients with fever and encephalitis near the areas where the viruses were isolated. This investigation suggests that Japanese encephalitis virus, Sindbis virus, and lesser-known arboviruses circulate and may be infecting humans in the China-Myanmar-Laos border region.

  8. Light manipulation of mosquito behaviour: acute and sustained photic suppression of biting activity in the Anopheles gambiae malaria mosquito.

    Sheppard, Aaron D; Rund, Samuel S C; George, Gary F; Clark, Erin; Acri, Dominic J; Duffield, Giles E

    2017-06-16

    Host-seeking behaviours in anopheline mosquitoes are time-of-day specific, with a greater propensity for nocturnal biting. We investigated how a short exposure to light presented during the night or late day can inhibit biting activity and modulate flight activity behaviour. Anopheles gambiae (s.s.), maintained on a 12:12 LD cycle, were exposed transiently to white light for 10-min at the onset of night and the proportion taking a blood meal in a human biting assay was recorded every 2 h over an 8-h duration. The pulse significantly reduced biting propensity in mosquitoes 2 h following administration, in some trials for 4 h, and with no differences detected after 6 h. Conversely, biting levels were significantly elevated when mosquitoes were exposed to a dark treatment during the late day, suggesting that light suppresses biting behaviour even during the late daytime. These data reveal a potent effect of a discrete light pulse on biting behaviour that is both immediate and sustained. We expanded this approach to develop a method to reduce biting propensity throughout the night by exposing mosquitoes to a series of 6- or 10-min pulses presented every 2 h. We reveal both an immediate suppressive effect of light during the exposure period and 2 h after the pulse. This response was found to be effective during most times of the night: however, differential responses that were time-of-day specific suggest an underlying circadian property of the mosquito physiology that results in an altered treatment efficacy. Finally, we examined the immediate and sustained effects of light on mosquito flight activity behaviour following exposure to a 30-min pulse, and observed activity suppression during early night, and elevated activity during the late night. As mosquitoes and malaria parasites are becoming increasingly resistant to insecticide and drug treatment respectively, there is a necessity for the development of innovative control strategies beyond insecticide

  9. Degenerações periféricas da retina em pacientes candidatos à cirurgia refrativa Peripheral retina degeneration in patients who are candidates for refractive surgery

    Paulo Henrique de Avila Morales

    2001-02-01

    Full Text Available Objetivo: O objetivo desse estudo é verificar em indivíduos míopes candidatos à cirurgia refrativa a prevalência dos diferentes tipos de lesões retinianas periféricas degenerativas de acordo com o tipo de miopia. Métodos: De forma prospectiva, no período de um ano, foram examinados os olhos dos pacientes no Setor de Cirurgia Refrativa do Departamento de Oftalmologia da Universidade Federal de São Paulo - Escola Paulista de Medicina que durante a sua consulta inicial apresentassem refração com equivalente esférico superior ou igual a -1,00 dioptria esférica, e não tivessem antecedentes pessoais de doença ou cirurgia ocular no período. Foi investigada a existência de lesões e/ou degenerações periféricas predisponentes ao descolamento regmatogênico de retina. Resultados: O grupo foi composto, em sua maioria, por adultos jovens (média de idade de 31 anos. Foram observados olhos com miopia baixa (263 olhos, 31%, moderada (300 olhos, 36% e alta (277 olhos, 33%; em 35,4% dos pacientes (27% dos olhos foram encontradas degenerações periféricas, sendo o branco com e sem pressão a alteração mais freqüente (23,4% dos pacientes ou 17,5% dos olhos. Entre as lesões predisponentes ao descolamento regmatogênico da retina, a mais encontrada foi a degeneração em treliça (8,6% dos pacientes ou 6% dos olhos. Conclusões: As alterações periféricas predisponentes ou não ao descolamento regmatogênico de retina apresentaram aumento de prevalência de acordo com o aumento do grau de miopia, com exceção das roturas. Todos os pacientes com miopia alta e candidatos à cirurgia refrativa devem ter a periferia retiniana de ambos os olhos examinada.Purpose: To verify, in myopic individuals who are candidates for refractive surgery, the prevalence of different types of peripheral degenerative lesions of the retina, according to the type of myopia. Methods: Prospectively, during a one-year interval, we examined the eyes of patients in

  10. Quantitative analysis of retina layer elasticity based on automatic 3D segmentation (Conference Presentation)

    He, Youmin; Qu, Yueqiao; Zhang, Yi; Ma, Teng; Zhu, Jiang; Miao, Yusi; Humayun, Mark; Zhou, Qifa; Chen, Zhongping

    2017-02-01

    Age-related macular degeneration (AMD) is an eye condition that is considered to be one of the leading causes of blindness among people over 50. Recent studies suggest that the mechanical properties in retina layers are affected during the early onset of disease. Therefore, it is necessary to identify such changes in the individual layers of the retina so as to provide useful information for disease diagnosis. In this study, we propose using an acoustic radiation force optical coherence elastography (ARF-OCE) system to dynamically excite the porcine retina and detect the vibrational displacement with phase resolved Doppler optical coherence tomography. Due to the vibrational mechanism of the tissue response, the image quality is compromised during elastogram acquisition. In order to properly analyze the images, all signals, including the trigger and control signals for excitation, as well as detection and scanning signals, are synchronized within the OCE software and are kept consistent between frames, making it possible for easy phase unwrapping and elasticity analysis. In addition, a combination of segmentation algorithms is used to accommodate the compromised image quality. An automatic 3D segmentation method has been developed to isolate and measure the relative elasticity of every individual retinal layer. Two different segmentation schemes based on random walker and dynamic programming are implemented. The algorithm has been validated using a 3D region of the porcine retina, where individual layers have been isolated and analyzed using statistical methods. The errors compared to manual segmentation will be calculated.

  11. Histologic correlation of in vivo optical coherence tomography images of the human retina

    Chen, T.; Cense, B.; Miller, J.S.; Rubin, P. A. D.; Deschler, D. G.; Gragoudas, E. S.; de Boer, J.F.

    2006-01-01

    Purpose: To correlate in vivo human retina optical coherence tomography (OCT)3 images with histology. Design: Case series. Methods: Linear OCT3 scans through the macula and optic nerve were obtained in three eyes of three patients who then underwent exenteration surgery for orbital cancers. OCT3

  12. Photopic spectral sensitivities of the red and the yellow field of the pigeon retina

    Wortel, J.F.; Wubbels, R.J.; Nuboer, J.F.W.

    1984-01-01

    The spectral sensitivities of the red field and the yellow field in the retina of the homing pigeon (Columba Livia) were determined on the basis of ERG responses. Between 450 and 550 nm the relative spectral sensitivity of the yellow field turned out to be higher than that of the red field. The

  13. Müller cells express the cannabinoid CB2 receptor in the vervet monkey retina

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian

    2013-01-01

    The presence of the cannabinoid receptor type 1 (CB1R) has been largely documented in the rodent and primate retinae in recent years. There is, however, some controversy concerning the presence of the CB2 receptor (CB2R) within the central nervous system. Only recently, CB2R has been found in the...

  14. Bipolar cell gap junctions serve major signaling pathways in the human retina.

    Kántor, Orsolya; Varga, Alexandra; Nitschke, Roland; Naumann, Angela; Énzsöly, Anna; Lukáts, Ákos; Szabó, Arnold; Németh, János; Völgyi, Béla

    2017-08-01

    Connexin36 (Cx36) constituent gap junctions (GJ) throughout the brain connect neurons into functional syncytia. In the retina they underlie the transmission, averaging and correlation of signals prior conveying visual information to the brain. This is the first study that describes retinal bipolar cell (BC) GJs in the human inner retina, whose function is enigmatic even in the examined animal models. Furthermore, a number of unique features (e.g. fovea, trichromacy, midget system) necessitate a reexamination of the animal model results in the human retina. Well-preserved postmortem human samples of this study are allowed to identify Cx36 expressing BCs neurochemically. Results reveal that both rod and cone pathway interneurons display strong Cx36 expression. Rod BC inputs to AII amacrine cells (AC) appear in juxtaposition to AII GJs, thus suggesting a strategic AII cell targeting by rod BCs. Cone BCs serving midget, parasol or koniocellular signaling pathways display a wealth of Cx36 expression to form homologously coupled arrays. In addition, they also establish heterologous GJ contacts to serve an exchange of information between parallel signaling streams. Interestingly, a prominent Cx36 expression was exhibited by midget system BCs that appear to maintain intimate contacts with bistratified BCs serving other pathways. These findings suggest that BC GJs in parallel signaling streams serve both an intra- and inter-pathway exchange of signals in the human retina.

  15. Correlations between specific patterns of spontaneous activity and stimulation efficiency in degenerated retina.

    Christine Haselier

    Full Text Available Retinal prostheses that are currently used to restore vision in patients suffering from retinal degeneration are not adjusted to the changes occurring during the remodeling process of the retina. Recent studies revealed abnormal rhythmic activity in the retina of genetic mouse models of retinitis pigmentosa. Here we describe this abnormal activity also in a pharmacologically-induced (MNU mouse model of retinal degeneration. To investigate how this abnormal activity affects the excitability of retinal ganglion cells, we recorded the electrical activity from whole mounted retinas of rd10 mice and MNU-treated mice using a microelectrode array system and applied biphasic current pulses of different amplitude and duration to stimulate ganglion cells electrically. We show that the electrical stimulation efficiency is strongly reduced in degenerated retinas, in particular when abnormal activity such as oscillations and rhythmic firing of bursts of action potentials can be observed. Using a prestimulus pulse sequence, we could abolish rhythmic retinal activity. Under these conditions, the stimulation efficiency was enhanced in a few cases but not in the majority of tested cells. Nevertheless, this approach supports the idea that modified stimulation protocols could help to improve the efficiency of retinal prostheses in the future.

  16. Lateral feedback from monophasic horizontal cells to cones in carp retina. I. Experiments

    Kamermans, M.; van Dijk, B. W.; Spekreijse, H.; Zweypfenning, R. C.

    1989-01-01

    The spatial and color coding of the monophasic horizontal cells were studied in light- and dark-adapted retinae. Slit displacement experiments revealed differences in integration area for the different cone inputs of the monophasic horizontal cells. The integration area measured with a 670-nm

  17. Adaptive colour contrast coding in the salamander retina efficiently matches natural scene statistics.

    Genadiy Vasserman

    Full Text Available The visual system continually adjusts its sensitivity to the statistical properties of the environment through an adaptation process that starts in the retina. Colour perception and processing is commonly thought to occur mainly in high visual areas, and indeed most evidence for chromatic colour contrast adaptation comes from cortical studies. We show that colour contrast adaptation starts in the retina where ganglion cells adjust their responses to the spectral properties of the environment. We demonstrate that the ganglion cells match their responses to red-blue stimulus combinations according to the relative contrast of each of the input channels by rotating their functional response properties in colour space. Using measurements of the chromatic statistics of natural environments, we show that the retina balances inputs from the two (red and blue stimulated colour channels, as would be expected from theoretical optimal behaviour. Our results suggest that colour is encoded in the retina based on the efficient processing of spectral information that matches spectral combinations in natural scenes on the colour processing level.

  18. Expression of Endoplasmic Reticulum Stress-Related Factors in the Retinas of Diabetic Rats

    Shu Yan

    2012-01-01

    Full Text Available Recent reports show that ER stress plays an important role in diabetic retinopathy (DR, but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ. The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP, and synoviolin(HRD1 were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.

  19. Ocular distribution of antioxidant enzyme paraoxonase & its alteration in cataractous lens & diabetic retina

    Subramaniam Rajesh Bharathidevi

    2017-01-01

    Interpretation & conclusions: Distribution of PON enzyme and its activity in ocular tissues is reported here. The study revealed maximal PON activity in lens and retina, which are prone to higher oxidative stress. Differential activities of PON were observed in the lens and retinal tissues from cataractous and diabetic patients, respectively.

  20. Interaction between the soma and the axon terminal of horizontal cells in carp retina

    Kamermans, M.; van Dijk, B. W.; Spekreijse, H.

    1990-01-01

    In teleost retina, the receptive fields of horizontal cell axon terminals have a larger space constant than the receptive fields of the horizontal cell somata. Generally this difference in receptive field size is attributed to the cell coupling which is assumed to be stronger in the horizontal axon