Multimodal LA-ICP-MS and nanoSIMS imaging enables copper mapping within photoreceptor megamitochondria in a zebrafish model of Menkes disease.

Science.gov (United States)

Ackerman, Cheri M; Weber, Peter K; Xiao, Tong; Thai, Bao; Kuo, Tiffani J; Zhang, Emily; Pett-Ridge, Jennifer; Chang, Christopher J

2018-03-01

Copper is essential for eukaryotic life, and animals must acquire this nutrient through the diet and distribute it to cells and organelles for proper function of biological targets. Indeed, mutations in the central copper exporter ATP7A contribute to a spectrum of diseases, including Menkes disease, with symptoms ranging from neurodegeneration to lax connective tissue. As such, a better understanding of the fundamental impacts of ATP7A mutations on in vivo copper distributions is of relevance to those affected by these diseases. Here we combine metal imaging and optical imaging techniques at a variety of spatial resolutions to identify tissues and structures with altered copper levels in the Calamity gw71 zebrafish model of Menkes disease. Rapid profiling of tissue slices with LA-ICP-MS identified reduced copper levels in the brain, neuroretina, and liver of Menkes fish compared to control specimens. High resolution nanoSIMS imaging of the neuroretina, combined with electron and confocal microscopies, identified the megamitochondria of photoreceptors as loci of copper accumulation in wildtype fish, with lower levels of megamitochondrial copper observed in Calamity gw71 zebrafish. Interestingly, this localized copper decrease does not result in impaired photoreceptor development or altered megamitochondrial morphology, suggesting the prioritization of copper at sufficient levels for maintaining essential mitochondrial functions. Together, these data establish the Calamity gw71 zebrafish as an optically transparent in vivo model for the study of neural copper misregulation, illuminate a role for the ATP7A copper exporter in trafficking copper to the neuroretina, and highlight the utility of combining multiple imaging techniques for studying metals in whole organism settings with spatial resolution.

Multifractal resilience and viability

Science.gov (United States)

Tchiguirinskaia, I.; Schertzer, D. J. M.

2017-12-01

The term resilience has become extremely fashionable and there had been many attempts to provide operational definition and in fact metrics going beyond a set of more or less ad-hoc indicators. The viability theory (Aubin and Saint-Pierre, 2011) have been used to give a rather precise mathematical definition of resilience (Deffuant and Gilbert, 2011). However, it does not grasp the multiscale nature of resilience that is rather fundamental as particularly stressed by Folke et al (2010). In this communication, we first recall a preliminary attempt (Tchiguirinskaia et al., 2014) to define multifractal resilience with the help of the maximal probable singularity. Then we extend this multifractal approach to the capture basin of the viability, therefore the resilient basin. Aubin, J P, A. Bayen, and P Saint-Pierre (2011). Viability Theory. New Directions. Springer, Berlin,. Deffuant, G. and Gilbert, N. (eds) (2011) Viability and Resilience of Complex Systems. Springer Berlin.Folke, C., S R Carpenter, B Walker, M Sheffer, T Chapin, and J Rockstroem (2010). Resilience thinking: integrating re- silience, adaptability and transformability. Ecology and So- ciety, 14(4):20, Tchiguirinskaia,I., D. Schertzer, , A. Giangola-Murzyn and T. C. Hoang (2014). Multiscale resilience metrics to assess flood. Proceedings of ICCSA 2014, Normandie University, Le Havre, France -.

NINL and DZANK1 Co-function in Vesicle Transport and Are Essential for Photoreceptor Development in Zebrafish

NARCIS (Netherlands)

Dona, M.; Bachmann-Gagescu, R.; Texier, Y.; Toedt, G.; Hetterschijt, L.; Tonnaer, E.L.; Peters, T.A.; Beersum, S.E.C. van; Bergboer, J.G.M.; Horn, N.; Vrieze, E. de; Slijkerman, R.W.N.; Reeuwijk, J. van; Flik, G.; Keunen, J.E.E.; Ueffing, M.; Gibson, T.J.; Roepman, R.; Boldt, K.; Kremer, H.; Wijk, E. van

2015-01-01

Ciliopathies are Mendelian disorders caused by dysfunction of cilia, ubiquitous organelles involved in fluid propulsion (motile cilia) or signal transduction (primary cilia). Retinal dystrophy is a common phenotypic characteristic of ciliopathies since photoreceptor outer segments are specialized

Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

Science.gov (United States)

Omori, Yoshihiro; Katoh, Kimiko; Sato, Shigeru; Muranishi, Yuki; Chaya, Taro; Onishi, Akishi; Minami, Takashi; Fujikado, Takashi; Furukawa, Takahisa

2011-01-01

In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO) mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

Analysis of transcriptional regulatory pathways of photoreceptor genes by expression profiling of the Otx2-deficient retina.

Directory of Open Access Journals (Sweden)

Yoshihiro Omori

Full Text Available In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. We previously reported that Otx2 conditional knockout (CKO mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome of the Otx2 CKO retina, we compared expression profile of Otx2 CKO and wild-type retinas at P1 and P12 using microarray. We observed that expression of 101- and 1049-probe sets significantly decreased in the Otx2 CKO retina at P1 and P12, respectively, whereas, expression of 3- and 4149-probe sets increased at P1 and P12, respectively. We found that expression of genes encoding transcription factors involved in photoreceptor development, including Crx, Nrl, Nr2e3, Esrrb, and NeuroD, was markedly down-regulated in the Otx2 CKO at both P1 and P12. Furthermore, we identified three human retinal disease loci mapped in close proximity to certain down-regulated genes in the Otx2 CKO retina including Ccdc126, Tnfsf13 and Pitpnm1, suggesting that these genes are possibly responsible for these diseases. These transcriptome data sets of the Otx2 CKO retina provide a resource on developing rods and cones to further understand the molecular mechanisms underlying photoreceptor development, function and disease.

Amphioxus photoreceptors insights into the evolution of vertebrate opsins, vision and circadian rhythmicity

Czech Academy of Sciences Publication Activity Database

Pergner, Jiří; Kozmik, Zbyněk

2017-01-01

Roč. 61, č. 10-12 (2017), s. 665-681 ISSN 0214-6282 R&D Projects: GA ČR GA17-15374S; GA MŠk(CZ) LM2015062; GA MŠk LO1419 Institutional support: RVO:68378050 Keywords : chordate * opsin evolution * photoreceptor * eye evolution * phototransduction Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 1.981, year: 2016

UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

Science.gov (United States)

Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B.; Niyogi, Krishna K.; Goldschmidt-Clermont, Michel

2016-01-01

Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast. PMID:27930292

UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii.

Science.gov (United States)

Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B; Niyogi, Krishna K; Ulm, Roman; Goldschmidt-Clermont, Michel

2016-12-20

Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast.

In vivo imaging of human photoreceptor mosaic with wavefront sensorless adaptive optics optical coherence tomography.

Science.gov (United States)

Wong, Kevin S K; Jian, Yifan; Cua, Michelle; Bonora, Stefano; Zawadzki, Robert J; Sarunic, Marinko V

2015-02-01

Wavefront sensorless adaptive optics optical coherence tomography (WSAO-OCT) is a novel imaging technique for in vivo high-resolution depth-resolved imaging that mitigates some of the challenges encountered with the use of sensor-based adaptive optics designs. This technique replaces the Hartmann Shack wavefront sensor used to measure aberrations with a depth-resolved image-driven optimization algorithm, with the metric based on the OCT volumes acquired in real-time. The custom-built ultrahigh-speed GPU processing platform and fast modal optimization algorithm presented in this paper was essential in enabling real-time, in vivo imaging of human retinas with wavefront sensorless AO correction. WSAO-OCT is especially advantageous for developing a clinical high-resolution retinal imaging system as it enables the use of a compact, low-cost and robust lens-based adaptive optics design. In this report, we describe our WSAO-OCT system for imaging the human photoreceptor mosaic in vivo. We validated our system performance by imaging the retina at several eccentricities, and demonstrated the improvement in photoreceptor visibility with WSAO compensation.

Lysergic acid diethylamide causes photoreceptor cell damage through inducing inflammatory response and oxidative stress.

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Hu, Qi-Di; Xu, Ling-Li; Gong, Yan; Wu, Guo-Hai; Wang, Yu-Wen; Wu, Shan-Jun; Zhang, Zhe; Mao, Wei; Zhou, Yu-Sheng; Li, Qin-Bo; Yuan, Jian-Shu

2018-01-19

Lysergic acid diethylamide (LSD), a classical hallucinogen, was used as a popular and notorious substance of abuse in various parts of the world. Its abuse could result in long-lasting abnormalities in retina and little is known about the exact mechanism. This study was to investigate the effect of LSD on macrophage activation state at non-toxic concentration and its resultant toxicity to photoreceptor cells. Results showed that cytotoxicity was caused by LSD on 661 W cells after co-culturing with RAW264.7 cells. Treatment with LSD-induced RAW264.7 cells to the M1 phenotype, releasing more pro-inflammatory cytokines, and increasing the M1-related gene expression. Moreover, after co-culturing with RAW264.7 cells, significant oxidative stress in 661 W cells treated with LSD was observed, by increasing the level of malondialdehyde (MDA) and reactive oxygen species (ROS), and decreasing the level of glutathione (GSH) and the activity of superoxide dismutase (SOD). Our study demonstrated that LSD caused photoreceptor cell damage by inducing inflammatory response and resultant oxidative stress, providing the scientific rationale for the toxicity of LSD to retina.

Rod and cone photoreceptor cells produce ROS in response to stress in a live retinal explant system.

LENUS (Irish Health Repository)

Bhatt, Lavinia

2010-01-01

PURPOSE: The production of reactive oxygen species (ROS) can lead to oxidative stress, which is a strong contributory factor to many ocular diseases. In this study, the removal of trophic factors is used as a model system to investigate the effects of stress in the retina. The aims were to determine if both rod and cone photoreceptor cells produce ROS when they are deprived of trophic factor support and to demonstrate if the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzymes are responsible for this ROS production. METHODS: Retinas were explanted from mice aged between postnatal days 8-10 and cultured overnight. The following morning, confocal microscopy combined with various fluorescent probes was used to detect the production of ROS. Each time peanut agglutinin (PNA), a cone photoreceptor marker, was used to facilitate orientation of the retina. Dihydroethidium and dihydrorhodamine 123 (DHR123) were used to determine which cells produce ROS. Subsequently, western blots of retinal serial sections were used to detect the presence of Noxs in the different retinal layers. The Nox inhibitor apocynin was then tested to determine if it altered the production of ROS within these cells. RESULTS: Live retinal explants, viewed at high magnifications using confocal microscopy, displayed an increase in the fluorescent products of dihydroethidium and DHR123 upon serum removal when compared to controls. DHR123 fluorescence, once oxidized, localized to mitochondria and was found in the same focal plane as the PNA staining. This showed that cones and rods produced ROS when stressed. Retinal serial sectioning established that the photoreceptor layer expressed Nox4, dual oxidase (Duox) 1, and Duox2 at varying levels. Finally, the Nox inhibitor apocynin decreased the burst stimulated by the stress of serum removal. CONCLUSIONS: Confocal microscopy and PNA staining allowed differentiation of cell types within the outermost layers of the retina, demonstrating

Threats to and viability of the giant anteater, Myrmecophaga tridactyla (Pilosa: Myrmecophagidae, in a protected Cerrado remnant encroached by urban expansion in central Brazil

Directory of Open Access Journals (Sweden)

Milena F. Diniz

2013-04-01

Full Text Available Urbanization poses a serious threat to wildlife populations inhabiting native vegetation remnants surrounded by the expanding urban and suburban sprawl. The close contact with human activities causes not only direct impacts, such as habitat loss, but also indirect negative effects, such as population isolation, roadkills and anthropogenic fires. The Parque Nacional de Brasília is a large Cerrado remnant almost completely surrounded by the city of Brasília, in central Brazil. Here, we use population viability analysis to model the impacts of urbanization on a population of Myrmecophaga tridactyla (Linnaeus, 1758 inhabiting that park. Our results show that roadkill mortality is by far the most serious threat to the long-term persistence of the giant anteater in the study site. The implementation of measures to better control vehicle speed in the vicinity of the park is urgently needed if we expect the giant anteater population to be effectively protected in the Parque Nacional de Brasília.

Blue and ultraviolet-B light photoreceptors in parsley cells

International Nuclear Information System (INIS)

Ensminger, P.A.; Schaefer, E.

1992-01-01

The authors studied UV-B photoreception in parsley cell cultures with physiological experiments involving temperature shifts and examined the possible role of flavin in blue and UV-B light photo-reception. Cells irradiated with UV-B light (0.5-15 min) at 2 o C have the same fluence requirement for chalcone synthase and flavonoid induction as controls irradiated at 25 o C. This is indicative of a purely photochemical reaction. Cells fed with riboflavin and irradiated with 6 h of UV-containing white light synthesize higher levels of chalcone synthase and flavonoid than unfed controls. This effect did not occur with blue light. These results indicate that flavin-sensitization requires excitation of flavin and the UV-B light photoreceptor. (author)

Global gene expression analysis in a mouse model for Norrie disease: late involvement of photoreceptor cells.

Science.gov (United States)

Lenzner, Steffen; Prietz, Sandra; Feil, Silke; Nuber, Ulrike A; Ropers, H-Hilger; Berger, Wolfgang

2002-09-01

Mutations in the NDP gene give rise to a variety of eye diseases, including classic Norrie disease (ND), X-linked exudative vitreoretinopathy (EVRX), retinal telangiectasis (Coats disease), and advanced retinopathy of prematurity (ROP). The gene product is a cystine-knot-containing extracellular signaling molecule of unknown function. In the current study, gene expression was determined in a mouse model of ND, to unravel disease-associated mechanisms at the molecular level. Gene transcription in the eyes of 2-year-old Ndp knockout mice was compared with that in the eyes of age-matched wild-type control animals, by means of cDNA subtraction and microarrays. Clones (n = 3072) from the cDNA subtraction libraries were spotted onto glass slides and hybridized with fluorescently labeled RNA-derived targets. More than 230 differentially expressed clones were sequenced, and their expression patterns were verified by virtual Northern blot analysis. Numerous gene transcripts that are absent or downregulated in the eye of Ndp knockout mice are photoreceptor cell specific. In younger Ndp knockout mice (up to 1 year old), however, all these transcripts were found to be expressed at normal levels. The identification of numerous photoreceptor cell-specific transcripts with a reduced expression in 2-year-old, but not in young, Ndp knockout mice indicates that normal gene expression in these light-sensitive cells of mutant mice is established and maintained over a long period and that rods and cones are affected relatively late in the mouse model of ND. Obviously, the absence of the Ndp gene product is not compatible with long-term survival of photoreceptor cells in the mouse.

Photosensory transduction in unicellular eukaryotes: a comparison between related ciliates Blepharisma japonicum and Stentor coeruleus and photoreceptor cells of higher organisms.

Science.gov (United States)

Sobierajska, Katarzyna; Fabczak, Hanna; Fabczak, Stanisław

2006-06-01

Blepharisma japonicum and Stentor coeruleus are related ciliates, conspicuous by their photosensitivity. They are capable of avoiding illuminated areas in the surrounding medium, gathering exclusively in most shaded places (photodispersal). Such behaviour results mainly from motile photophobic response occurring in ciliates. This light-avoiding response is observed during a relatively rapid increase in illumination intensity (light stimulus) and consists of cessation of cell movement, a period of backward movement (ciliary reversal), followed by a forward swimming, usually in a new direction. The photosensitivity of ciliates is ascribed to their photoreceptor system, composed of pigment granules, containing the endogenous photoreceptor -- blepharismin in Blepharisma japonicum, and stentorin in Stentor coeruleus. A light stimulus, applied to both ciliates activates specific stimulus transduction processes leading to the electrical changes at the plasma membrane, correlated with a ciliary reversal during photophobic response. These data indicate that both ciliates Blepharisma japonicum and Stentor coeruleus, the lower eukaryotes, are capable of transducing the perceived light stimuli in a manner taking place in some photoreceptor cells of higher eukaryotes. Similarities and differences concerning particular stages of light transduction in eukaryotes at different evolutional levels are discussed in this article.

An N-Terminal ER Export Signal Facilitates the Plasma Membrane Targeting of HCN1 Channels in Photoreceptors.

Science.gov (United States)

Pan, Yuan; Laird, Joseph G; Yamaguchi, David M; Baker, Sheila A

2015-06-01

Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels are widely expressed in the retina. In photoreceptors, the hyperpolarization-activated current (Ih) carried by HCN1 is important for shaping the light response. It has been shown in multiple systems that trafficking HCN1 channels to specific compartments is key to their function. The localization of HCN1 in photoreceptors is concentrated in the plasma membrane of the inner segment (IS). The mechanisms controlling this localization are not understood. We previously identified a di-arginine endoplasmic reticulum (ER) retention motif that negatively regulates the surface targeting of HCN1. In this study, we sought to identify a forward trafficking signal that could counter the function of the ER retention signal. We studied trafficking of HCN1 and several mutants by imaging their subcellular localization in transgenic X. laevis photoreceptors. Velocity sedimentation was used to assay the assembly state of HCN1 channels. We found the HCN1 N-terminus can redirect a membrane reporter from outer segments (OS) to the plasma membrane of the IS. The sequence necessary for this behavior was mapped to a 20 amino acid region containing a leucine-based ER export motif. The ER export signal is necessary for forward trafficking but not channel oligomerization. Moreover, this ER export signal alone counteracted the di-arginine ER retention signal. We identified an ER export signal in HCN1 that functions with the ER retention signal to maintain equilibrium of HCN1 between the endomembrane system and the plasma membrane.

Cobalamin C Deficiency Shows a Rapidly Progressing Maculopathy With Severe Photoreceptor and Ganglion Cell Loss

Science.gov (United States)

Bonafede, Lucas; Ficicioglu, Can H.; Serrano, Leona; Han, Grace; Morgan, Jessica I. W.; Mills, Monte D.; Forbes, Brian J.; Davidson, Stefanie L.; Binenbaum, Gil; Kaplan, Paige B.; Nichols, Charles W.; Verloo, Patrick; Leroy, Bart P.; Maguire, Albert M.; Aleman, Tomas S.

2015-01-01

Purpose To describe in detail the retinal structure and function of a group of patients with cobalamin C (cblC) disease. Methods Patients (n = 11, age 4 months to 15 years) with cblC disease (9/11, early onset) diagnosed by newborn screening underwent complete ophthalmic examinations, fundus photography, near-infrared reflectance imaging, and spectral-domain optical coherence tomography (SD-OCT). Electroretinograms (ERGs) were performed in a subset of patients. Results Patients carried homozygous or compound heterozygote mutations in the methylmalonic aciduria and homocystinuria type C (MMACHC) gene. Late-onset patients had a normal exam. All early-onset patients showed a maculopathy; older subjects had a retina-wide degeneration (n = 4; >7 years of age). In general, retinal changes were first observed before 1 year of age and progressed within months to a well-established maculopathy. Pseudocolobomas were documented in three patients. Measurable visual acuities ranged from 20/200 to 20/540. Nystagmus was present in 8/11 patients; 5/6 patients had normal ERGs; 1/6 had reduced rod-mediated responses. Spectral-domain OCT showed macular thinning, with severe ganglion cell layer (GCL) and outer nuclear layer (ONL) loss. Inner retinal thickening was observed in areas of total GCL/ONL loss. A normal lamination pattern in the peripapillary nasal retina was often seen despite severe central and/or retina-wide disease. Conclusions Patients with early-onset cblC and MMACHC mutations showed an early-onset, unusually fast-progressing maculopathy with severe central ONL and GCL loss. An abnormally thickened inner retina supports a remodeling response to both photoreceptor and ganglion cell degeneration and/or an interference with normal development in early-onset cblC. PMID:26658511

Mfsd2a Is a Transporter for the Essential ω-3 Fatty Acid Docosahexaenoic Acid (DHA) in Eye and Is Important for Photoreceptor Cell Development.

Science.gov (United States)

Wong, Bernice H; Chan, Jia Pei; Cazenave-Gassiot, Amaury; Poh, Rebecca W; Foo, Juat Chin; Galam, Dwight L A; Ghosh, Sujoy; Nguyen, Long N; Barathi, Veluchamy A; Yeo, Sia W; Luu, Chi D; Wenk, Markus R; Silver, David L

2016-05-13

Eye photoreceptor membrane discs in outer rod segments are highly enriched in the visual pigment rhodopsin and the ω-3 fatty acid docosahexaenoic acid (DHA). The eye acquires DHA from blood, but transporters for DHA uptake across the blood-retinal barrier or retinal pigment epithelium have not been identified. Mfsd2a is a newly described sodium-dependent lysophosphatidylcholine (LPC) symporter expressed at the blood-brain barrier that transports LPCs containing DHA and other long-chain fatty acids. LPC transport via Mfsd2a has been shown to be necessary for human brain growth. Here we demonstrate that Mfsd2a is highly expressed in retinal pigment epithelium in embryonic eye, before the development of photoreceptors, and is the primary site of Mfsd2a expression in the eye. Eyes from whole body Mfsd2a-deficient (KO) mice, but not endothelium-specific Mfsd2a-deficient mice, were DHA-deficient and had significantly reduced LPC/DHA transport in vivo Fluorescein angiography indicated normal blood-retinal barrier function. Histological and electron microscopic analysis indicated that Mfsd2a KO mice exhibited a specific reduction in outer rod segment length, disorganized outer rod segment discs, and mislocalization of and reduction in rhodopsin early in postnatal development without loss of photoreceptors. Minor photoreceptor cell loss occurred in adult Mfsd2a KO mice, but electroretinography indicated visual function was normal. The developing eyes of Mfsd2a KO mice had activated microglia and up-regulation of lipogenic and cholesterogenic genes, likely adaptations to loss of LPC transport. These findings identify LPC transport via Mfsd2a as an important pathway for DHA uptake in eye and for development of photoreceptor membrane discs. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Mechanisms underlying stage-1 TRPL channel translocation in Drosophila photoreceptors.

Directory of Open Access Journals (Sweden)

Minh-Ha Lieu

Full Text Available TRP channels function as key mediators of sensory transduction and other cellular signaling pathways. In Drosophila, TRP and TRPL are the light-activated channels in photoreceptors. While TRP is statically localized in the signaling compartment of the cell (the rhabdomere, TRPL localization is regulated by light. TRPL channels translocate out of the rhabdomere in two distinct stages, returning to the rhabdomere with dark-incubation. Translocation of TRPL channels regulates their availability, and thereby the gain of the signal. Little, however, is known about the mechanisms underlying this trafficking of TRPL channels.We first examine the involvement of de novo protein synthesis in TRPL translocation. We feed flies cycloheximide, verify inhibition of protein synthesis, and test for TRPL translocation in photoreceptors. We find that protein synthesis is not involved in either stage of TRPL translocation out of the rhabdomere, but that re-localization to the rhabdomere from stage-1, but not stage-2, depends on protein synthesis. We also characterize an ex vivo eye preparation that is amenable to biochemical and genetic manipulation. We use this preparation to examine mechanisms of stage-1 TRPL translocation. We find that stage-1 translocation is: induced with ATP depletion, unaltered with perturbation of the actin cytoskeleton or inhibition of endocytosis, and slowed with increased membrane sterol content.Our results indicate that translocation of TRPL out of the rhabdomere is likely due to protein transport, and not degradation/re-synthesis. Re-localization from each stage to the rhabdomere likely involves different strategies. Since TRPL channels can translocate to stage-1 in the absence of ATP, with no major requirement of the cytoskeleton, we suggest that stage-1 translocation involves simple diffusion through the apical membrane, which may be regulated by release of a light-dependent anchor in the rhabdomere.

Mechanism of immune suppression by ultraviolet irradiation in vivo. I. Evidence for the existence of a unique photoreceptor in skin and its role in photoimmunology

International Nuclear Information System (INIS)

De Fabo, E.C.; Noonan, F.P.

1983-01-01

UV irradiation of mice causes a systemic immune alteration that can be detected either by suppression of the immunologic rejection of UV-induced tumors, or by suppression of contact hypersensitivity (CHS). Suppression of these two immunologic responses has similar photobiologic characteristics and in both cases is associated with the generation of antigen-specific suppressor T cells. To identify whether a specific photoreceptor for this effect exists, the relative wavelength effectiveness (action spectrum) was determined for the UV-induced suppression of CHS. Narrow bands of UV (half bandwidth 3 nm) were used at 10 wavelengths from 250 to 320 nm to obtain dose-response curves. The action spectrum derived from the dose-response curves has a maximum between 260 and 270 nm, a shoulder at 280-290 nm, and declines steadily to approximately 3% of maximum at 320 nm. The finding of such a clearly defined wavelength dependence implies the presence of a specific photoreceptor for this effect. Removing the stratum corneum by tape stripping before UV irradiation prevented the suppression of CHS using 254-nm radiation, suggesting the photoreceptor is superficially located in the skin. The hypothesis is advanced that the photoreceptor for systemic UV-induced immunosuppression of contact hypersensitivity may be urocanic acid. As such, it may also play a role in UV-induced carcinogenesis via the production of tumor-specific suppressor cells

Bifurcation analysis of a photoreceptor interaction model for Retinitis Pigmentosa

Science.gov (United States)

Camacho, Erika T.; Radulescu, Anca; Wirkus, Stephen

2016-09-01

Retinitis Pigmentosa (RP) is the term used to describe a diverse set of degenerative eye diseases affecting the photoreceptors (rods and cones) in the retina. This work builds on an existing mathematical model of RP that focused on the interaction of the rods and cones. We non-dimensionalize the model and examine the stability of the equilibria. We then numerically investigate other stable modes that are present in the system for various parameter values and relate these modes to the original problem. Our results show that stable modes exist for a wider range of parameter values than the stability of the equilibrium solutions alone, suggesting that additional approaches to preventing cone death may exist.

Loss of ift122, a Retrograde Intraflagellar Transport (IFT) Complex Component, Leads to Slow, Progressive Photoreceptor Degeneration Due to Inefficient Opsin Transport*

Science.gov (United States)

Boubakri, Meriam; Chaya, Taro; Hirata, Hiromi; Kajimura, Naoko; Kuwahara, Ryusuke; Ueno, Akiko; Malicki, Jarema; Furukawa, Takahisa; Omori, Yoshihiro

2016-01-01

In the retina, aberrant opsin transport from cell bodies to outer segments leads to retinal degenerative diseases such as retinitis pigmentosa. Opsin transport is facilitated by the intraflagellar transport (IFT) system that mediates the bidirectional movement of proteins within cilia. In contrast to functions of the anterograde transport executed by IFT complex B (IFT-B), the precise functions of the retrograde transport mediated by IFT complex A (IFT-A) have not been well studied in photoreceptor cilia. Here, we analyzed developing zebrafish larvae carrying a null mutation in ift122 encoding a component of IFT-A. ift122 mutant larvae show unexpectedly mild phenotypes, compared with those of mutants defective in IFT-B. ift122 mutants exhibit a slow onset of progressive photoreceptor degeneration mainly after 7 days post-fertilization. ift122 mutant larvae also develop cystic kidney but not curly body, both of which are typically observed in various ciliary mutants. ift122 mutants display a loss of cilia in the inner ear hair cells and nasal pit epithelia. Loss of ift122 causes disorganization of outer segment discs. Ectopic accumulation of an IFT-B component, ift88, is observed in the ift122 mutant photoreceptor cilia. In addition, pulse-chase experiments using GFP-opsin fusion proteins revealed that ift122 is required for the efficient transport of opsin and the distal elongation of outer segments. These results show that IFT-A is essential for the efficient transport of outer segment proteins, including opsin, and for the survival of retinal photoreceptor cells, rendering the ift122 mutant a unique model for human retinal degenerative diseases. PMID:27681595

Pollen viability and membrane lipid composition

NARCIS (Netherlands)

Bilsen, van D.G.J.L.

1993-01-01

In this thesis membrane lipid composition is studied in relation to pollen viability during storage. Chapter 1 reviews pollen viability, membranes in the dry state and membrane changes associated with cellular aging. This chapter is followed by a study of age-related changes in phospholipid

Nuclear Import of the Parsley bZIP Transcription Factor CPRF2 Is Regulated by Phytochrome Photoreceptors

Science.gov (United States)

Kircher, Stefan; Wellmer, Frank; Nick, Peter; Rügner, Alexander; Schäfer, Eberhard; Harter, Klaus

1999-01-01

In plants, light perception by photoreceptors leads to differential expression of an enormous number of genes. An important step for differential gene expression is the regulation of transcription factor activities. To understand these processes in light signal transduction we analyzed the three well-known members of the common plant regulatory factor (CPRF) family from parsley (Petroselinum crispum). Here, we demonstrate that these CPRFs, which belong to the basic- region leucine-zipper (bZIP) domain-containing transcription factors, are differentially distributed within parsley cells, indicating different regulatory functions within the regulatory networks of the plant cell. In particular, we show by cell fractionation and immunolocalization approaches that CPRF2 is transported from the cytosol into the nucleus upon irradiation due to action of phytochrome photoreceptors. Two NH2-terminal domains responsible for cytoplasmic localization of CPRF2 in the dark were characterized by deletion analysis using a set of CPRF2-green fluorescent protein (GFP) gene fusion constructs transiently expressed in parsley protoplasts. We suggest that light-induced nuclear import of CPRF2 is an essential step in phytochrome signal transduction. PMID:9922448

Na+/K(+)pump activity in photoreceptors of the blowfly Calliphora : A model analysis based on membrane potential measurements

NARCIS (Netherlands)

Gerster, U; Stavenga, DG; Backhaus, W

Na+/K+-pump activity and intracellular Na+ and K+ concentration changes in blowfly photoreceptors are derived from intracellular potential measurements in vivo with a model based on the Goldman-Hodgkin-Katz theory for membrane currents. The relation between the intracellular Na+ concentration and

Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

Directory of Open Access Journals (Sweden)

Narsing A Rao

Full Text Available The small heat shock protein, αA-crystallin null (αA-/- mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU. In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB, a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice, which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ, both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

Small heat shock protein αA-crystallin prevents photoreceptor degeneration in experimental autoimmune uveitis.

Science.gov (United States)

Rao, Narsing A; Saraswathy, Sindhu; Pararajasegaram, Geeta; Bhat, Suraj P

2012-01-01

The small heat shock protein, αA-crystallin null (αA-/-) mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU). In this report we demonstrate that intravenous administration of αA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only αA and not αB-crystallin (αB), a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of αA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing αA-/- and wild type mice with EAU as donors and Rag2-/- as the recipient mice), which indicate that αA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that αA administration causes marked reduction in Th1 cytokines (TNF-α, IL-12 and IFN-γ), both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that αA protection, against photoreceptor loss in EAU, is associated with systemic suppression of both the adaptive and innate immune responses.

Structural aspects of the antioxidant activity of lutein in a model of photoreceptor membranes

Science.gov (United States)

Wisniewska-Becker, Anna; Nawrocki, Grzegorz; Duda, Mariusz; Subczynski, Witold K.

2014-01-01

It was shown that in membranes containing raft domains, the macular xanthophylls lutein and zeaxanthin are not distributed uniformly, but are excluded from saturated raft domains and about ten times more concentrated in unsaturated bulk lipids. The selective accumulation of lutein and zeaxanthin in direct proximity to unsaturated lipids, which are especially susceptible to lipid peroxidation, could be very important as far as their antioxidant activity is concerned. Therefore, the protective role of lutein against lipid peroxidation was investigated in membranes made of raft-forming mixtures and in models of photoreceptor outer segment membranes and compared with their antioxidant activity in homogeneous membranes composed of unsaturated lipids. Lipid peroxidation was induced by photosensitized reactions using rose Bengal and monitored by an MDA-TBA test, an iodometric assay, and oxygen consumption (using EPR spectroscopy and the mHCTPO spin label as an oxygen probe). The results show that lutein protects unsaturated lipids more effectively in membranes made of raft-forming mixtures than in homogeneous membranes. This suggests that the selective accumulation of macular xanthophylls in the most vulnerable regions of photoreceptor membranes may play an important role in enhancing their antioxidant properties and ability to prevent age-related macular diseases (such as age-related macular degeneration [AMD]). PMID:22428148

Algae viability over time in a ballast water sample

Science.gov (United States)

Gollasch, Stephan; David, Matej

2018-03-01

The biology of vessels' ballast water needs to be analysed for several reasons, one of these being performance tests of ballast water management systems. This analysis includes a viability assessment of phytoplankton. To overcome logistical problems to get algae sample processing gear on board of a vessel to document algae viability, samples may be transported to land-based laboratories. Concerns were raised how the storage conditions of the sample may impact algae viability over time and what the most appropriate storage conditions were. Here we answer these questions with a long-term algae viability study with daily sample analysis using Pulse-Amplitude Modulated (PAM) fluorometry. The sample was analysed over 79 days. We tested different storage conditions: fridge and room temperature with and without light. It seems that during the first two weeks of the experiment the viability remains almost unchanged with a slight downwards trend. In the continuing period, before the sample was split, a slightly stronger downwards viability trend was observed, which occurred at a similar rate towards the end of the experiment. After the sample was split, the strongest viability reduction was measured for the sample stored without light at room temperature. We concluded that the storage conditions, especially regarding temperature and light exposure, have a stronger impact on algae viability compared to the storage duration and that inappropriate storage conditions reduce algal viability. A sample storage time of up to two weeks in a dark and cool environment has little influence on the organism viability. This indicates that a two week time duration between sample taking on board a vessel and the viability measurement in a land-based laboratory may not be very critical.

Natural History of the Central Structural Abnormalities in Choroideremia: A Prospective Cross-Sectional Study.

Science.gov (United States)

Aleman, Tomas S; Han, Grace; Serrano, Leona W; Fuerst, Nicole M; Charlson, Emily S; Pearson, Denise J; Chung, Daniel C; Traband, Anastasia; Pan, Wei; Ying, Gui-Shuang; Bennett, Jean; Maguire, Albert M; Morgan, Jessica I W

2017-03-01

To describe in detail the central retinal structure of a large group of patients with choroideremia (CHM). A prospective, cross-sectional, descriptive study. Patients (n = 97, age 6-71 years) with CHM and subjects with normal vision (n = 44; ages 10-50 years) were included. Subjects were examined with spectral-domain optical coherence tomography (SD OCT) and near-infrared reflectance imaging. Visual acuity (VA) was measured during their encounter or obtained from recent ophthalmic examinations. Visual thresholds were measured in a subset of patients (n = 24) with automated static perimetry within the central regions (±15°) examined with SD OCT. Visual acuity and visual thresholds; total nuclear layer, inner nuclear layer (INL), and outer nuclear layer (ONL) thicknesses; and horizontal extent of the ONL and the photoreceptor outer segment (POS) interdigitation zone (IZ). Earliest abnormalities in regions with normally appearing retinal pigment epithelium (RPE) were the loss of the POS and ellipsoid zone associated with rod dysfunction. Transition zones (TZs) from relatively preserved retina to severe ONL thinning and inner retinal thickening moved centripetally with age. Most patients (88%) retained VAs better than 20/40 until their fifth decade of life. The VA decline coincided with migration of the TZ near the foveal center. There were outer retinal tubulations in degenerated, nonatrophic retina in the majority (69%) of patients. In general, RPE abnormalities paralleled photoreceptor degeneration, although there were regions with detectable but abnormally thin ONL co-localizing with severe RPE depigmentation and choroidal thinning. Abnormalities of the POS and rod dysfunction are the earliest central abnormalities observed in CHM. Foveal function is relatively preserved until the fifth decade of life. Migration of the TZs to the foveal center with foveal thinning and structural disorganization heralded central VA loss. The relationships established may help

Multifocal central serous chorioretinopathy with photoreceptor-retinal pigment epithelium diastasis in heritable pulmonary arterial hypertension

DEFF Research Database (Denmark)

Li, Xiao Qiang; Pryds, Anders; Carlsen, Jørn

2015-01-01

PURPOSE: To report atypical central serous chorioretinopathy and choroidal thickening in a patient with heritable pulmonary arterial hypertension. METHODS: A 40-year-old man with heritable pulmonary arterial hypertension presented with blurred vision in his left eye and was followed up for 1 year...

Human Usher 1B/mouse shaker-1: the retinal phenotype discrepancy explained by the presence/absence of myosin VIIA in the photoreceptor cells.

Science.gov (United States)

el-Amraoui, A; Sahly, I; Picaud, S; Sahel, J; Abitbol, M; Petit, C

1996-08-01

Usher syndrome type 1 (USH1) associates severe congenital deafness, vestibular dysfunction and progressive retinitis pigmentosa leading to blindness. The gene encoding myosin VIIA is responsible for USH1B. Mutations in the murine orthologous gene lead to the shaker-1 phenotype, which manifests cochlear and vestibular dysfunction, without any retinal defect. To address this phenotypic discrepancy, the expression of myosin VIIA in retinal cells was analyzed in human and mouse during embryonic development and adult life. In the human embryo, myosin VIIA was present first in the pigment epithelium cells, and later in these cells as well as in the photoreceptor cells. In the adult human retina, myosin VIIA was present in both cell types. In contrast, in mouse, only pigment epithelium cells expressed the protein throughout development and adult life. Myosin VIIA was also found to be absent in the photoreceptor cells of other rodents (rat and guinea-pig), whereas these cells expressed the protein in amphibians, avians and primates. These observations suggest that retinitis pigmentosa of USH1B results from a primary rod and cone defect. The USH1B/shaker-1 paradigm illustrates a species-specific cell pattern of gene expression as a possible cause for the discrepancy between phenotypes involving defective orthologous genes in man and mouse. Interestingly, in the photoreceptor cells, myosin VIIA is mainly localized in the inner and base of outer segments as well as in the synaptic ending region where it is co-localized with the synaptic vesicles. Therefore, we suggest that myosin VIIA might play a role in the trafficking of ribbon-synaptic vesicle complexes and the renewal processes of the outer photoreceptor disks.

Terminology for pregnancy loss prior to viability

DEFF Research Database (Denmark)

Kolte, A M; Bernardi, L A; Christiansen, O B

2015-01-01

Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from...... different centres. In our opinion, terminology and definitions should be based on clinical findings, and when possible, transvaginal ultrasound. With this Early Pregnancy Consensus Statement, it is our goal to provide clear and consistent terminology for pregnancy loss prior to viability....

Analyze the economic and environmental viability in distributed generation of electric power from renewable sources

International Nuclear Information System (INIS)

Jantim Neto, Humberto

2010-01-01

This paper brings a brief of economical and social environmental analysis about distributed electric's energy generation, based on a comparison to centralized generation. The motivation of the proposed analysis has its origin on a reflection about politics and scheming directed to Brazilian's energy sector. This study has renewable energy resources as setting, represented for Belo Monte generation's plant and undertaking registered on the Reservation's Energy Auction 2010. The study took into account economics and technical aspects, whereas the viability analysis was formed from benefits got from different forms of electric's generation. The conclusions of this shows that distributed electric's energy generation may have economics and socio environment benefits over centralized generation. (author)

Quantitative and Topographical Analysis of the Losses of Cone Photoreceptors and Retinal Ganglion Cells Under Taurine Depletion.

Science.gov (United States)

Hadj-Saïd, Wahiba; Froger, Nicolas; Ivkovic, Ivana; Jiménez-López, Manuel; Dubus, Élisabeth; Dégardin-Chicaud, Julie; Simonutti, Manuel; Quénol, César; Neveux, Nathalie; Villegas-Pérez, María Paz; Agudo-Barriuso, Marta; Vidal-Sanz, Manuel; Sahel, Jose-Alain; Picaud, Serge; García-Ayuso, Diego

2016-09-01

Taurine depletion is known to induce photoreceptor degeneration and was recently found to also trigger retinal ganglion cell (RGC) loss similar to the retinal toxicity of vigabatrin. Our objective was to study the topographical loss of RGCs and cone photoreceptors, with a distinction between the two cone types (S- and L- cones) in an animal model of induced taurine depletion. We used the taurine transporter (Tau-T) inhibitor, guanidoethane sulfonate (GES), to induce taurine depletion at a concentration of 1% in the drinking water. Spectral-domain optical coherence tomography (SD-OCT) and electroretinograms (ERG) were performed on animals after 2 months of GES treatment administered through the drinking water. Retinas were dissected as wholemounts and immunodetection of Brn3a (RGC), S-opsin (S-cones), and L-opsin (L-cones) was performed. The number of Brn3a+ RGCs, and L- and S-opsin+ cones was automatically quantified and their retinal distribution studied using isodensity maps. The treatment resulted in a significant reduction in plasma taurine levels and a profound dysfunction of visual performance as shown by ERG recordings. Optical coherence tomography analysis revealed that the retina was thinner in the taurine-depleted group. S-opsin+cones were more affected (36%) than L-opsin+cones (27%) with greater cone cell loss in the dorsal area whereas RGC loss (12%) was uniformly distributed. This study confirms that taurine depletion causes RGC and cone loss. Electroretinograms results show that taurine depletion induces retinal dysfunction in photoreceptors and in the inner retina. It establishes a gradient of cell loss depending on the cell type from S-opsin+cones, L-opsin+cones, to RGCs. The greater cell loss in the dorsal retina and of the S-cone population may underline different cellular mechanisms of cellular degeneration and suggests that S-cones may be more sensitive to light-induced retinal toxicity enhanced by the taurine depletion.

Abundance, viability and culturability of Antarctic bacteria

Digital Repository Service at National Institute of Oceanography (India)

LokaBharathi, P.A.; DeSouza, M.J.B.D.; Nair, S.; Chandramohan, D.

The viability of total number of bacteria decide the mineralisation rate in any ecosystem and ultimately the fertility of the region. This study aims at establishing the extent of viability in the standing stock of the Antarctic bacterial population...

Modelling the optical response of human retinal photoreceptors to plane wave illumination with the finite integration technique

Science.gov (United States)

Akhlagh Moayed, Alireza; Dang, Shannon; Ramahi, Omar M.; Bizheva, Kostadinka K.

2009-02-01

The early stages of ocular diseases such as Diabetic Retinopathy are manifested by morphological changes in retinal tissue occurring on cellular level. Therefore, a number of ophthalmic diseases can be diagnosed at an early stage by detecting spatial and temporal variations in the scattering profile of retinal tissue. It was recently demonstrated that, OCT can be used to probe the functional response of retinal photoreceptors to external light stimulation [1]-[3]. fUHROCT measures localized differential changes in the retina reflectivity over time resulting from external light stimulation of the retina. Currently the origins of the observed reflectivity changes are not well understood. However, due to the complex nature of retinal physiology using purely experimental approaches in this case is problematic. For example fUHROCT is sensitive to small changes in the refractive index of biological tissue which as demonstrated previously, can result from a number of processes such as membrane hyperpolarization, osmotic swelling, metabolic changes, etc. In this paper, we present a computational model of interaction between photoreceptor cells and optical plane wave based on the Finite Integration Technique (FIT).

A novel Usher protein network at the periciliary reloading point between molecular transport machineries in vertebrate photoreceptor cells.

Science.gov (United States)

Maerker, Tina; van Wijk, Erwin; Overlack, Nora; Kersten, Ferry F J; McGee, Joann; Goldmann, Tobias; Sehn, Elisabeth; Roepman, Ronald; Walsh, Edward J; Kremer, Hannie; Wolfrum, Uwe

2008-01-01

The human Usher syndrome (USH) is the most frequent cause of combined deaf-blindness. USH is genetically heterogeneous with at least 12 chromosomal loci assigned to three clinical types, USH1-3. Although these USH types exhibit similar phenotypes in human, the corresponding gene products belong to very different protein classes and families. The scaffold protein harmonin (USH1C) was shown to integrate all identified USH1 and USH2 molecules into protein networks. Here, we analyzed a protein network organized in the absence of harmonin by the scaffold proteins SANS (USH1G) and whirlin (USH2D). Immunoelectron microscopic analyses disclosed the colocalization of all network components in the apical inner segment collar and the ciliary apparatus of mammalian photoreceptor cells. In this complex, whirlin and SANS directly interact. Furthermore, SANS provides a linkage to the microtubule transport machinery, whereas whirlin may anchor USH2A isoform b and VLGR1b (very large G-protein coupled receptor 1b) via binding to their cytodomains at specific membrane domains. The long ectodomains of both transmembrane proteins extend into the gap between the adjacent membranes of the connecting cilium and the apical inner segment. Analyses of Vlgr1/del7TM mice revealed the ectodomain of VLGR1b as a component of fibrous links present in this gap. Comparative analyses of mouse and Xenopus photoreceptors demonstrated that this USH protein network is also part of the periciliary ridge complex in Xenopus. Since this structural specialization in amphibian photoreceptor cells defines a specialized membrane domain for docking and fusion of transport vesicles, we suggest a prominent role of the USH proteins in cargo shipment.

Biological activity is the likely origin of the intersection between the photoreceptor inner and outer segments of the rat retina as determined by optical coherence tomography

Directory of Open Access Journals (Sweden)

Yamauchi Y

2011-11-01

Full Text Available Yasuyuki Yamauchi, Hiromichi Yagi, Yoshihiko Usui, Keisuke Kimura, Tsuyoshi Agawa, Rintaro Tsukahara, Naoyuki Yamakawa, Hiroshi GotoDepartment of Ophthalmology, Tokyo Medical University Hospital, Tokyo, JapanBackground: Recent research on macular diseases has prompted investigations into the condition of the intersection between the photoreceptor inner and outer segments (IS/OS and the relationship with retinal photoreceptor abnormalities. Although the origin of the IS/OS in optical coherence tomography (OCT images is unclear, it may be related to either the cellular activity of the photoreceptors or the structure of the OS disks. To address this question, we compared the IS/OS status in OCT images of rat retinas before and after euthanasia.Methods: OCT images were taken before and after euthanasia in four eyes of two Brown Norway rats. After the OCT images were taken, the rats were used for histopathological studies to confirm that retinal structures were intact.Results: Before euthanasia, the IS/OS and external limiting membrane (ELM line were clearly identifiable on the OCT images. However, after euthanasia, neither the IS/OS nor the ELM line was evident in three out of four eyes, and a faint IS/OS and an ELM line were identified in one eye. Histopathological analysis did not show any abnormalities in the retina in any of the four eyes.Conclusion: The origin of the IS/OS identified in OCT images is likely related to the biological activities of the photoreceptor cells.Keywords: IS/OS, OCT, histopathology, biological activity

Coping with 'Dark Sides of the Sun' through Photoreceptor Signaling.

Science.gov (United States)

Demarsy, Emilie; Goldschmidt-Clermont, Michel; Ulm, Roman

2018-03-01

Plants grow in constantly changing environments, including highly variable light intensities. Sunlight provides the energy that drives photosynthesis and is thus of the utmost importance for plant growth and the generation of oxygen, which the majority of life on Earth depends on. However, exposure to either insufficient or excess levels of light can have detrimental effects and cause light stress. Whereas exposure to insufficient light limits photosynthetic activity, resulting in 'energy starvation', exposure to excess light can damage the photosynthetic apparatus. Furthermore, strong sunlight is associated with high levels of potentially damaging UV-B radiation. Different classes of photoreceptors play important roles in coping with the negative aspects of sunlight, for which specific mechanisms are emerging that are reviewed here. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of myocardial viability by MR imaging

International Nuclear Information System (INIS)

Sandstede, Joern J.W.

2003-01-01

Diagnosis of myocardial viability after infarction focuses on the prediction of functional improvement of dysfunctional myocardium after revascularization therapy. Magnetic resonance imaging provides different approaches for the detection of myocardial viability. Measurement of end-diastolic wall thickness is easy to perform and has a high sensitivity, but a low specificity, and can only be used 4 months after myocardial infarction due to infarct healing processes. Low-dose dobutamine stress has a good sensitivity with a high specificity for the prediction of wall motion improvement, but this is only true for patients with a singular dysfunctional area and only slightly depressed cardiac function. Late enhancement allows for direct visualization of necrotic or scarred tissue. By measuring the transmural extent of late enhancement, the probability of mechanical improvement can precisely be given. Imaging of microvascular obstruction by first-pass perfusion or late enhancement gives additional information on viability and patient prognosis. Metabolic imaging techniques, such as 31 P-MR spectroscopy and 23 Na-MR imaging, provide further insights into the mechanisms of myocardial infarction and viability. In conclusion, cardiac MRI offers several clinically usable approaches for the assessment of myocardial viability and will probably become the method of choice in the near future. (orig.)

Differentiation and Transplantation of Embryonic Stem Cell-Derived Cone Photoreceptors into a Mouse Model of End-Stage Retinal Degeneration

Directory of Open Access Journals (Sweden)

Kamil Kruczek

2017-06-01

Full Text Available The loss of cone photoreceptors that mediate daylight vision represents a leading cause of blindness, for which cell replacement by transplantation offers a promising treatment strategy. Here, we characterize cone differentiation in retinas derived from mouse embryonic stem cells (mESCs. Similar to in vivo development, a temporal pattern of progenitor marker expression is followed by the differentiation of early thyroid hormone receptor β2-positive precursors and, subsequently, photoreceptors exhibiting cone-specific phototransduction-related proteins. We establish that stage-specific inhibition of the Notch pathway increases cone cell differentiation, while retinoic acid signaling regulates cone maturation, comparable with their actions in vivo. MESC-derived cones can be isolated in large numbers and transplanted into adult mouse eyes, showing capacity to survive and mature in the subretinal space of Aipl1−/− mice, a model of end-stage retinal degeneration. Together, this work identifies a robust, renewable cell source for cone replacement by purified cell suspension transplantation.

Regulatory arrestin cycle secures the fidelity and maintenance of the fly photoreceptor cell.

Science.gov (United States)

Byk, T; Bar-Yaacov, M; Doza, Y N; Minke, B; Selinger, Z

1993-01-01

Excitation of fly photoreceptor cells is initiated by photoisomerization of rhodopsin to the active form of metarhodopsin. Fly metarhodopsin is thermostable, does not bleach, and does not regenerate spontaneously to rhodopsin. For this reason, the activity of metarhodopsin must be stopped by an effective termination reaction. On the other hand, there is also a need to restore the inactivated photopigment to an excitable state in order to keep a sufficient number of photopigment molecules available for excitation. The following findings reveal how these demands are met. The photopigment undergoes rapid phosphorylation upon photoconversion of rhodopsin to metarhodopsin and an efficient Ca2+ dependent dephosphorylation upon regeneration of metarhodopsin to rhodopsin. Phosphorylation decreases the ability of metarhodopsin to activate the guanine nucleotide-binding protein. Binding of 49-kDa arrestin further quenches the activity of metarhodopsin and protects it from dephosphorylation. Light-dependent binding and release of 49-kDa arrestin from metarhodopsin- and rhodopsin-containing membranes, respectively, directs the dephosphorylation reaction toward rhodopsin. This ensures the return of phosphorylated metarhodopsin to the rhodopsin pool without initiating transduction in the dark. Assays of rhodopsin dephosphorylation in the Drosophila retinal degeneration C (rdgC) mutant, a mutant in a gene previously cloned and predicted to encode a serine/threonine protein phosphatase, reveal that phosphorylated rhodopsin is a major substrate for the rdgC phosphatase. We propose that mutations resulting in either a decrease or an improper regulation of rhodopsin phosphatase activity bring about degeneration of the fly photoreceptor cells. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8446607

Structure and function of the interphotoreceptor matrix surrounding retinal photoreceptor cells.

Science.gov (United States)

Ishikawa, Makoto; Sawada, Yu; Yoshitomi, Takeshi

2015-04-01

The interphotoreceptor matrix (IPM) is a highly organized structure with interconnected domains surrounding cone and rod photoreceptor cells and extends throughout the subretinal space. Based on known roles of the extracellular matrix in other tissues, the IPM is thought to have several prominent functions including serving as a receptor for growth factors, regulating retinoid transport, participating in cytoskeletal organization in surrounding cells, and regulation of oxygen and nutrient transport. In addition, a number of studies suggest that the IPM also may play a significant role in the etiology of retinal degenerative disorders. In this review, we describe the present knowledge concerning the structure and function of the IPM under physiological and pathological conditions. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Doctors' perspectives on the viability of rural practice.

Science.gov (United States)

Jones, J A; Humphreys, J S; Adena, M A

2004-01-01

Private practitioners play a vital role in meeting the health needs of rural communities. However, the prospect of operating a private practice business in rural Australia seems to be increasingly unattractive, because many communities are forced to recruit salaried or overseas-trained doctors. This study focuses on rural practices as businesses whose viability influences their attractiveness for the recruitment and retention of practitioners. The specific objectives are to ascertain which factors contribute to or threaten practice viability in rural areas, and whether they vary according to the degree of rurality or geographical remoteness. This study is based on data collected from a national study into the viability of rural general practice undertaken jointly by the Rural Doctors Association of Australia and Monash University School of Rural Health Bendigo. The Rural Remote and Metropolitan Area (RRMA) classification was used as the indicator of rurality. The study surveyed all general practitioners practising in rural or remote regions of Australia (RRMAs 3 to 7). Only practitioners with some financial interest in the practice were selected for this analysis. Free-text responses to the two questions 'What are the key factors contributing to the viability of your practice?' and 'What factors would put the viability of your practice at risk?' were analysed using qualitative content analysis. Factors were derived iteratively through higher-level aggregation of responses. Chi-square tests were used to make comparisons across the RRMA categories. The national survey achieved a response rate of 35% of the entire population of GPs practising in RRMA 3 to 7 regions. Of these, 1050 respondents were relevant to this analysis. Seven major factors were identified by practitioners as the main contributors to practice viability. 'Practice characteristics' was nominated by 59% of respondents, followed by 'Income' (31%), 'Personal circumstances', 'Workforce' and 'Community

Link overlap, viability, and mutual percolation in multiplex networks

International Nuclear Information System (INIS)

Min, Byungjoon; Lee, Sangchul; Lee, Kyu-Min; Goh, K.-I.

2015-01-01

Many real-world complex systems are best modeled by multiplex networks. The multiplexity has proved to have broad impact on the system’s structure and function. Most theoretical studies on multiplex networks to date, however, have largely ignored the effect of the link overlap across layers despite strong empirical evidences for its significance. In this article, we investigate the effect of the link overlap in the viability of multiplex networks, both analytically and numerically. After a short recap of the original multiplex viability study, the distinctive role of overlapping links in viability and mutual connectivity is emphasized and exploited for setting up a proper analytic framework. A rich phase diagram for viability is obtained and greatly diversified patterns of hysteretic behavior in viability are observed in the presence of link overlap. Mutual percolation with link overlap is revisited as a limit of multiplex viability problem, and the controversy between existing results is clarified. The distinctive role of overlapping links is further demonstrated by the different responses of networks under random removals of overlapping and non-overlapping links, respectively, as well as under several link-removal strategies. Our results show that the link overlap facilitates the viability and mutual percolation; at the same time, the presence of link overlap poses a challenge in analytical approaches to the problem

The UV-B Photoreceptor UVR8: From Structure to Physiology

Science.gov (United States)

Jenkins, Gareth I.

2014-01-01

Low doses of UV-B light (280 to 315 nm) elicit photomorphogenic responses in plants that modify biochemical composition, photosynthetic competence, morphogenesis, and defense. UV RESISTANCE LOCUS8 (UVR8) mediates photomorphogenic responses to UV-B by regulating transcription of a set of target genes. UVR8 differs from other known photoreceptors in that it uses specific Trp amino acids instead of a prosthetic chromophore for light absorption during UV-B photoreception. Absorption of UV-B dissociates the UVR8 dimer into monomers, initiating signal transduction through interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1. However, much remains to be learned about the physiological role of UVR8 and its interaction with other signaling pathways, the molecular mechanism of UVR8 photoreception, how the UVR8 protein initiates signaling, how it is regulated, and how UVR8 regulates transcription of its target genes. PMID:24481075

Transgenic Expression of Constitutively Active RAC1 Disrupts Mouse Rod Morphogenesis

Science.gov (United States)

Song, Hongman; Bush, Ronald A.; Vijayasarathy, Camasamudram; Fariss, Robert N.; Kjellstrom, Sten; Sieving, Paul A.

2014-01-01

Purpose. Dominant-active RAC1 rescues photoreceptor structure in Drosophila rhodopsin-null mutants, indicating an important role in morphogenesis. This report assesses the morphogenetic effect of activated RAC1 during mammalian rod photoreceptor development using transgenic mice that express constitutively active (CA) RAC1. Methods. Transgenic mice were generated by expressing CA RAC1 under control of the Rhodopsin promoter, and morphological features of the photoreceptors were evaluated by histology, immunohistochemistry, and transmission electron microscopy. Function was evaluated by electroretinography. Potential protein partners of CA RAC1 were identified by co-immunoprecipitation of retinal extracts. Results. Constitutively active RAC1 expression in differentiating rods disrupted outer retinal lamination as early as postnatal day (P)6, and many photoreceptor cell nuclei were displaced apically into the presumptive subretinal space. These photoreceptors did not develop normal inner and outer segments and had abnormal placement of synaptic elements. Some photoreceptor nuclei were also mislocalized into the inner nuclear layer. Extensive photoreceptor degeneration was subsequently observed in the adult animal. Constitutively active RAC1 formed a complex with the polarity protein PAR6 and with microtubule motor dynein in mouse retina. The normal localization of the PAR6 complex was disrupted in CA RAC1-expressing rod photoreceptors. Conclusions. Constitutively active RAC1 had a profound negative effect on mouse rod cell viability and development. Rod photoreceptors in the CA RAC1 retina exhibited a defect in polarity and migration. Constitutively active RAC1 disrupted rod morphogenesis and gave a phenotype resembling that found in the Crumbs mutant. PAR6 and dynein are two potential downstream effectors that may be involved in CA RAC1-mediated defective mouse photoreceptor morphogenesis. PMID:24651551

A viability analysis for a stock/price model

Science.gov (United States)

Jerry, Chakib; Raissi, Nadia

2012-09-01

We examine the conditions for the sustainability of a stock/price system based on the use of a marine renewable resource. Instead of studying the environmental and economic interactions in terms of optimal control, we focus on the viability of the system. These viability/crisis situations are defined by a set of economic state constraints. This constraints combine a guaranteed consumption and a minimum income for fishermen. Using the mathematical concept of viability kernel, we reveal that with only economics constraints we guarantee a perennial stock/price system.

Population-specific life histories contribute to metapopulation viability

Science.gov (United States)

Halsey, Samniqueka J.; Bell, Timothy J.; McEachern, A. Kathryn; Pavlovic, Noel B.

2016-01-01

Restoration efforts can be improved by understanding how variations in life-history traits occur within populations of the same species living in different environments. This can be done by first understanding the demographic responses of natural occurring populations. Population viability analysis continues to be useful to species management and conservation with sensitivity analysis aiding in the understanding of population dynamics. In this study, using life-table response experiments and elasticity analyses, we investigated how population-specific life-history demographic responses contributed to the metapopulation viability of the Federally threatened Pitcher's thistle (Cirsium pitcheri). Specifically, we tested the following hypotheses: (1) Subpopulations occupying different environments within a metapopulation have independent demographic responses and (2) advancing succession results in a shift from a demographic response focused on growth and fecundity to one dominated by stasis. Our results showed that reintroductions had a positive contribution to the metapopulation growth rate as compared to native populations which had a negative contribution. We found no difference in succession on the contribution to metapopulation viability. In addition, we identified distinct population-specific contributions to metapopulation viability and were able to associate specific life-history demographic responses. For example, the positive impact of Miller High Dunes population on the metapopulation growth rate resulted from high growth contributions, whereas increased time of plant in stasis for the State Park Big Blowout population resulted in negative contributions. A greater understanding of how separate populations respond in their corresponding environment may ultimately lead to more effective management strategies aimed at reducing extinction risk. We propose the continued use of sensitivity analyses to evaluate population-specific demographic influences on

Partial reconstitution of photoreceptor cGMP phosphodiesterase characteristics in cGMP phosphodiesterase-5.

Science.gov (United States)

Granovsky, A E; Artemyev, N O

2001-06-15

Photoreceptor cGMP phosphodiesterases (PDE6) are uniquely qualified to serve as effector enzymes in the vertebrate visual transduction cascade. In the dark-adapted photoreceptors, the activity of PDE6 is blocked via tight association with the inhibitory gamma-subunits (Pgamma). The Pgamma block is removed in the light-activated PDE6 by the visual G protein, transducin. Transducin-activated PDE6 exhibits an exceptionally high catalytic rate of cGMP hydrolysis ensuring high signal amplification. To identify the structural determinants for the inhibitory interaction with Pgamma and the remarkable cGMP hydrolytic ability, we sought to reproduce the PDE6 characteristics by mutagenesis of PDE5, a related cyclic GMP-specific, cGMP-binding PDE. PDE5 is insensitive to Pgamma and has a more than 100-fold lower k(cat) for cGMP hydrolysis. Our mutational analysis of chimeric PDE5/PDE6alpha' enzymes revealed that the inhibitory interaction of cone PDE6 catalytic subunits (PDE6alpha') with Pgamma is mediated primarily by three hydrophobic residues at the entry to the catalytic pocket, Met(758), Phe(777), and Phe(781). The maximal catalytic rate of PDE5 was enhanced by at least 10-fold with substitutions of PDE6alpha'-specific glycine residues for the corresponding PDE5 alanine residues, Ala(608) and Ala(612). The Gly residues are adjacent to the highly conserved metal binding motif His-Asn-X-X-His, which is essential for cGMP hydrolysis. Our results suggest that the unique Gly residues allow the PDE6 metal binding site to adopt a more favorable conformation for cGMP hydrolysis.

An automated algorithm for photoreceptors counting in adaptive optics retinal images

Science.gov (United States)

Liu, Xu; Zhang, Yudong; Yun, Dai

2012-10-01

Eyes are important organs of humans that detect light and form spatial and color vision. Knowing the exact number of cones in retinal image has great importance in helping us understand the mechanism of eyes' function and the pathology of some eye disease. In order to analyze data in real time and process large-scale data, an automated algorithm is designed to label cone photoreceptors in adaptive optics (AO) retinal images. Images acquired by the flood-illuminated AO system are taken to test the efficiency of this algorithm. We labeled these images both automatically and manually, and compared the results of the two methods. A 94.1% to 96.5% agreement rate between the two methods is achieved in this experiment, which demonstrated the reliability and efficiency of the algorithm.

Importance of Donor Chondrocyte Viability for Osteochondral Allografts.

Science.gov (United States)

Cook, James L; Stannard, James P; Stoker, Aaron M; Bozynski, Chantelle C; Kuroki, Keiichi; Cook, Cristi R; Pfeiffer, Ferris M

2016-05-01

Osteochondral allograft (OCA) transplantation provides a biological treatment option for functional restoration of large articular cartilage defects in multiple joints. While successful outcomes after OCA transplantation have been linked to viable donor chondrocytes, the importance of donor cell viability has not been comprehensively validated. To use a canine model to determine the importance of donor chondrocyte viability at the time of implantation with respect to functional success of femoral condylar OCAs based on radiographic, gross, cell viability, histologic, biochemical, and biomechanical outcome measures. Controlled laboratory study. After approval was obtained from the institutional animal care and use committee, adult female dogs (N = 16) were implanted with 8-mm cylindrical OCAs from male dogs in the lateral and medial femoral condyles of 1 knee. OCAs were preserved for 28 or 60 days after procurement, and chondrocyte viability was quantified before implantation. Two different storage media, temperatures, and time points were used to obtain a spectrum of percentage chondrocyte viability at the time of implantation. A successful outcome was defined as an OCA that was associated with graft integration, maintenance of hyaline cartilage, lack of associated cartilage disorder, and lack of fibrillation, fissuring, or fibrous tissue infiltration of the allograft based on subjective radiographic, gross, and histologic assessments at 6 months after implantation. Chondrocyte viability ranged from 23% to 99% at the time of implantation. All successful grafts had >70% chondrocyte viability at the time of implantation, and no graft with chondrocyte viability <70% was associated with a successful outcome. Live-dead stained sections and histologic findings with respect to cell morphological features suggested that successful grafts were consistently composed of viable chondrocytes in lacunae, while grafts that were not successful were composed of nonviable

Restoration of the photoreceptor layer and improvement of visual acuity in successfully treated optic disc pit maculopathy: a long follow-up study by optical coherence tomography.

Science.gov (United States)

Theodossiadis, George P; Grigoropoulos, Vlassis G; Liarakos, Vasilis S; Rouvas, Alexandros; Emfietzoglou, Ioannis; Theodossiadis, Panagiotis G

2012-07-01

To investigate by optical coherence tomography (OCT) the evolution of the photoreceptor layer and its association with best-corrected visual acuity (BCVA) in optic disc pit (ODP) maculopathy after successful surgical treatment. Fourteen eyes of 14 patients were included in this study, and followed up from 36 to 95 months (mean 57.36 ± 18.32 months). The follow-up period started at the time of complete subretinal fluid absorption. Examination was performed by time-domain OCT before and after treatment. Spectral-domain OCT was used after treatment. Parameters assessed were type of elevation, central foveal thickness, time elapsed from onset to treatment, type of treatment, BCVA, and inner segment outer segment (IS/OS) junction line. The IS/OS junction was characterized after treatment as intact, interrupted, or absent (not distinguishable). Significant restoration of the IS/OS junction line was first noticed between 6 and 12 months after fluid absorption (p = 0.02; Wilcoxon signed rank test). Restoration was continuous up to the 24th month of postoperative examination after fluid absorption (p = 0.14; Wilcoxon signed rank test). BCVA was 0.99 ± 0.38 logMar before treatment, 0.81 ± 0.26 logMar (p = 0.011; paired t-test) immediately after fluid absorption and 0.61 ± 0.33 logMar (p = 0.026; one-way ANOVA) 24 months after fluid resolution. BCVA was significantly positively correlated with the integrity of the IS/OS junction line during follow-up (Pearson r = 0.775; p final photoreceptor layer condition and BCVA immediately after fluid absorption are the main factors predicting final BCVA after successful surgical treatment of ODP maculopathy.

Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis.

Science.gov (United States)

Grinton, Michael E; Sandinha, Maria T; Steel, David H W

2015-01-01

This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP) and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629-631]. Spectral domain optical coherence tomography (OCT) has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1-21]. This study was conducted as a single case report. A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM) peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction.

Assessment of bacterial endospore viability with fluorescent dyes.

Science.gov (United States)

Laflamme, C; Lavigne, S; Ho, J; Duchaine, C

2004-01-01

To validate three fluorescence viability assays designed primarily for vegetative cells on pure Bacillus endospores. Purified fresh and gamma-irradiated Bacillus endospores (Bacillus cereus, B. coagulans and two strains of B. subtilis) were used. The viability assays were: 5-cyano-2,3-diotolyl tetrazolium chloride (CTC) to test respiratory activity and early germination, DiBAC4(3) and Live/Dead BacLight to measure membrane energization and permeabilization, respectively. Gamma irradiation treatment completely eliminated spore culturability and was used as negative control. The untreated spores showed respiratory activity after 1 h of incubation and this was characteristic of almost 100% of spores after 24 h. The membrane potential assessment gave no answer about spore viability. A lower proportion of untreated spores had permeabilized membrane compared with gamma-irradiated spores using Live/Dead BacLight (P plate count. This study shows that fluorescence tests could be applied to assess viability in potentially pathogenic Bacillus spore preparations within 1 h.

Mitosis in neurons: Roughex and APC/C maintain cell cycle exit to prevent cytokinetic and axonal defects in Drosophila photoreceptor neurons.

Directory of Open Access Journals (Sweden)

Robert Ruggiero

Full Text Available The mechanisms of cell cycle exit by neurons remain poorly understood. Through genetic and developmental analysis of Drosophila eye development, we found that the cyclin-dependent kinase-inhibitor Roughex maintains G1 cell cycle exit during differentiation of the R8 class of photoreceptor neurons. The roughex mutant neurons re-enter the mitotic cell cycle and progress without executing cytokinesis, unlike non-neuronal cells in the roughex mutant that perform complete cell divisions. After mitosis, the binucleated R8 neurons usually transport one daughter nucleus away from the cell body into the developing axon towards the brain in a kinesin-dependent manner resembling anterograde axonal trafficking. Similar cell cycle and photoreceptor neuron defects occurred in mutants for components of the Anaphase Promoting Complex/Cyclosome. These findings indicate a neuron-specific defect in cytokinesis and demonstrate a critical role for mitotic cyclin downregulation both to maintain cell cycle exit during neuronal differentiation and to prevent axonal defects following failed cytokinesis.

Myocardial viability assessment using nuclear imaging

International Nuclear Information System (INIS)

Matsunari, Ichiro; Hisada, Kinichi; Taki, Junichi; Nakajima, Kenichi; Tonami, Norihisa

2003-01-01

Myocardial assessment continues to be an issue in patients with coronary artery disease and left ventricular dysfunction. Nuclear imaging has long played an important role in this field. In particular, PET imaging using 18 F-fluorodeoxyglucose is regarded as the metabolic gold standard of tissue viability, which has been supported by a wide clinical experience. Viability assessment using SPECT techniques has gained more wide-spread clinical acceptance than PET, because it is more widely available at lower cost. Moreover, technical advances in SPECT technology such as gated-SPECT further improve the diagnostic accuracy of the test. However, other imaging techniques such as dobutamine echocardiography have recently emerged as competitors to nuclear imaging. It is also important to note that they sometimes may work in a complementary fashion to nuclear imaging, indicating that an appropriate use of these techniques may significantly improve their overall accuracy. In keeping these circumstances in mind, further efforts are necessary to further improve the diagnostic performance of nuclear imaging as a reliable viability test. (author) 107 refs

Present assessment of myocardial viability by nuclear imaging.

Science.gov (United States)

Saha, G B; MacIntyre, W J; Brunken, R C; Go, R T; Raja, S; Wong, C O; Chen, E Q

1996-10-01

Prospective delineation of viable from nonviable myocardium in patients with coronary artery disease in an important factor in deciding whether a patient should be revascularized or treated medically. Two common techniques--single-photon emission computed tomography (SPECT) and positron-emission computed tomography (PET)--are used in nuclear medicine using various radiopharmaceuticals for the detection of myocardial viability in patients. Thallium-201 (201Tl) and technetium-99m (99mTc)-sestamibi are the common radiopharmaceuticals used in different protocols using SPECT, whereas fluoride-18 (18F)-fluorodeoxyglucose (FDG) and rubidium-82 (82Rb) are most widely used in PET. The SPECT protocols involve stress/redistribution, stress/redistribution/reinjection, and rest/redistribution imaging techniques. Many studies have compared the results of 201Tl and (99mTc)-sestamibi SPECT with those of FDG PET; in some studies, concordant results have been found between delayed thallium and FDG results, indicating that 201Tl, although considered a perfusion agent, shows myocardial viability. Discordant results in a number of studies have been found between sestamibi and FDG, suggesting that the efficacy of sestamibi as a viability marker has yet to be established. Radiolabeled fatty acids such as iodine-123 (123I)-para-iodophenylpentadecanoic acid and carbon-11 (11C)-palmitic acid have been used for the assessment of myocardial viability with limited success. 11C-labeled acetate is a good marker of oxidative metabolism in the heart and has been used to predict the reversibility of wall motion abnormalities. (18F)-FDG is considered the marker of choice for myocardial viability, although variable results are obtained under different physiological conditions. Detection of myocardial viability can be greatly improved by developing new equipment and radiopharmaceuticals of better quality.

The effects of storage conditions on the viability of ...

African Journals Online (AJOL)

SARAKA DANIEL

2015-01-07

Jan 7, 2015 ... E-mail: ndsaraka@yahoo.fr, ndsaraka@gmail.com. Tel: 225 ..... sample viability and control of contaminants that may mask the ... viability and composition of the Escherichia coli flora in faecal ... Microbiologie alimentaire, 8e.

A business model design framework for viability : a business ecosystem approach

NARCIS (Netherlands)

D'Souza, Austin; Velthuijsen, Hugo; Wortmann, J.C.; Huitema, George

2015-01-01

Purpose: To facilitate the design of viable business models by proposing a novel business model design framework for viability. Design: A design science research method is adopted to develop a business model design framework for viability. The business model design framework for viability is

Corneal epithelial cell viability of an ex vivo porcine eye model.

Science.gov (United States)

Chan, Ka Yin; Cho, Pauline; Boost, Maureen

2014-07-01

The aim was to assess the consistency of corneal epithelial cell viability of an ex vivo porcine eye model. Six porcine eye models (four test and two control) were prepared for each experiment. The model has a computer-controlled mechanical arm, which could move the eyelid of the porcine eye and apply phosphate buffered saline to simulate blinking and lacrimation. The four test eyes were set up to simulate evaporative dry eyes with simulated lacrimation and blinking (one blink and one drop of buffered saline per minute) over three hours. Control A models were set up to collect pre-experimental baseline data, while those of control B were the same as the test eyes but without lacrimation and blinking simulation. All porcine eyes were kept in a closed chamber with temperature and humidity well controlled. After three hours, the cells of all eyes (except control A, which were assessed immediately before commencement of the experiment) were assessed. The eyes were first dipped into 0.4 per cent trypan blue solution. Following the dissection and separation of the cells, the number of dead cells were then counted under the microscope with a field size of 0.25 mm(2). The experiment was repeated 11 times. No significant differences were found in the number of dead cells among the four test eyes in both the central and peripheral cornea. There were significantly more dead cells in the test eyes compared to control A but significantly less when compared to control B. More dead cells were found in the central cornea than the peripheral cornea in the test eyes but the difference was not observed in controls A and B. Epithelial cell viabilities among the four porcine eye models with simulated lacrimation and blinking were consistent. The majority of cells were viable before the experiment and simulated lacrimation and blinking maintained more viable cells over time. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

Viability and Virulence of Entomopathogenic Nematodes Exposed to Ultraviolet Radiation.

Science.gov (United States)

Shapiro-Ilan, David I; Hazir, Selcuk; Lete, Luis

2015-09-01

Entomopathogenic nematodes (EPNs) can be highly effective biocontrol agents, but their efficacy can be reduced due to exposure to environmental stress such as from ultraviolet (UV) radiation. Our objectives were to 1) compare UV tolerance among a broad array of EPN species, and 2) investigate the relationship between reduced nematode viability (after exposure to UV) and virulence. Nematodes exposed to a UV radiation (254 nm) for 10 or 20 min were assessed separately for viability (survival) and virulence to Galleria mellonella. We compared 9 different EPN species and 15 strains: Heterorhabditis bacteriophora (Baine, fl11, Oswego, and Vs strains), H. floridensis (332), H. georgiana (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All, Cxrd, DD136, and Sal strains), S. feltiae (SN), S. rarum (17C&E), and S. riobrave (355). In viability assessments, steinernematids, particularly strains of S. carpocapsae, generally exhibited superior UV tolerance compared with the heterorhabditids. However, some heterorhabditids tended to be more tolerant than others, e.g., H. megidis and H. bacteriophora (Baine) were most susceptible and H. bacteriophora (Vs) was the only heterorhabditid that did not exhibit a significant effect after 10 min of exposure. All heterorhabditids experienced reduced viability after 20 min exposure though several S. carpocapsae strains did not. In total, after 10 or 20 min exposure, the viability of seven nematode strains did not differ from their non-UV exposed controls. In virulence assays, steinernematids (particularly S. carpocapsae strains) also tended to exhibit higher UV tolerance. However, in contrast to the viability measurements, all nematodes experienced a reduction in virulence relative to their controls. Correlation analysis revealed that viability among nematode strains is not necessarily related to virulence. In conclusion, our results indicate that the impact of UV varies substantially among EPNs, and viability alone

Necrotic enlargement of cone photoreceptor cells and the release of high-mobility group box-1 in retinitis pigmentosa

Science.gov (United States)

Murakami, Y; Ikeda, Y; Nakatake, S; Tachibana, T; Fujiwara, K; Yoshida, N; Notomi, S; Nakao, S; Hisatomi, T; Miller, J W; Vavvas, DG; Sonoda, KH; Ishibashi, T

2015-01-01

Retinitis pigmentosa (RP) refers to a group of inherited retinal degenerations resulting form rod and cone photoreceptor cell death. The rod cell death due to deleterious genetic mutations has been shown to occur mainly through apoptosis, whereas the mechanisms and features of the secondary cone cell death have not been fully elucidated. Our previous study showed that the cone cell death in rd10 mice, an animal model of RP, involves necrotic features and is partly mediated by the receptor interacting protein kinase. However, the relevancy of necrotic cone cell death in human RP patients remains unknown. In the present study, we showed that dying cone cells in rd10 mice exhibited cellular enlargement, along with necrotic changes such as cellular swelling and mitochondrial rupture. In human eyes, live imaging of cone cells by adaptive optics scanning laser ophthalmoscopy revealed significantly increased percentages of enlarged cone cells in the RP patients compared with the control subjects. The vitreous of the RP patients contained significantly higher levels of high-mobility group box-1, which is released extracellularly associated with necrotic cell death. These findings suggest that necrotic enlargement of cone cells is involved in the process of cone degeneration, and that necrosis may be a novel target to prevent or delay the loss of cone-mediated central vision in RP. PMID:27551484

Performance assessment of smallholder irrigation in the Central Rift Valley of Ethiopia

NARCIS (Netherlands)

Halsema, van G.E.; Lencha, B.K.; Assefa, M.; Hengsdijk, H.; Wesseler, J.H.H.

2011-01-01

The recent increase in smallholder irrigation schemes in the Central Rift Valley of Ethiopia has been associated with the overexploitation of water resources, while the economic viability of these schemes has been questioned. This paper assesses water use efficiencies of the Haleku Irrigation Scheme

Spectroscopic studies of model photo-receptors: validation of a nanosecond time-resolved micro-spectrophotometer design using photoactive yellow protein and α-phycoerythrocyanin.

Science.gov (United States)

Purwar, Namrta; Tenboer, Jason; Tripathi, Shailesh; Schmidt, Marius

2013-09-13

Time-resolved spectroscopic experiments have been performed with protein in solution and in crystalline form using a newly designed microspectrophotometer. The time-resolution of these experiments can be as good as two nanoseconds (ns), which is the minimal response time of the image intensifier used. With the current setup, the effective time-resolution is about seven ns, determined mainly by the pulse duration of the nanosecond laser. The amount of protein required is small, on the order of 100 nanograms. Bleaching, which is an undesirable effect common to photoreceptor proteins, is minimized by using a millisecond shutter to avoid extensive exposure to the probing light. We investigate two model photoreceptors, photoactive yellow protein (PYP), and α-phycoerythrocyanin (α-PEC), on different time scales and at different temperatures. Relaxation times obtained from kinetic time-series of difference absorption spectra collected from PYP are consistent with previous results. The comparison with these results validates the capability of this spectrophotometer to deliver high quality time-resolved absorption spectra.

Influence of low temperature and frost duration on Phytophthora alni subsp. alni viability

Energy Technology Data Exchange (ETDEWEB)

Cerny, K.; Filipova, N.; Strnadova, V.

2012-11-01

Limits on the survival of P. alni subsp. alni (PAA) due to low temperature can be expected based on previously published laboratory and field studies. This study presents a laboratory experiment to test the influence of low temperature and frost duration on PAA viability. Ten PAA isolates were incubated at different temperatures (-0.1, -2.5, -5.0, -7.5, and -10.0 degree centigrade) and frost durations (0 - 7, 14, 21, and 28 days). A regression analysis confirmed the significant influence of both factors (low temperature and frost duration, and their interaction) on the survival of the pathogen under laboratory conditions. The survival and failure time analysis showed that the survival of the pathogen differs significantly after mild frost (all the isolates tested survived temperatures between -0.1 and -5.0 degree centigrade during the entire testing period) and heavy frost (the pathogen died after 21 days of incubation at -7.5 degree centigrade and after 2 days at -10.0 degree centigrade). Moreover, the viability of the pathogen decreased significantly if the temperature of -5.0 degree centigrade was maintained for at least 1 week and the temperature of -7.5 degree centigrade persisted in laboratory conditions for at least 4 days. The results of the study proved the pathogen to be very sensitive to heavy frost. The low-temperature limits for PAA occur regularly in Central Europe in January. It is probable that these temperatures can reduce PAA populations in diseased black alder stems. The climate change characterised by increases in the lowest minimum winter temperatures in Central Europe (as hypothesised by IPCC) may pose a significant risk for affected alder population in the area. (Author) 21 refs.

STUDY ON POLLEN VIABILITY AS BIOINDICATOR OF AIR QUALITY

Directory of Open Access Journals (Sweden)

Florentina ŞTEFLEA

2012-01-01

Full Text Available The aim of this research is to estimate the relationship between pollen viability and atmospheric pollution (in polluted and non-polluted conditions. The study was carried out in the city of Timisoara. Two areas, with different intensity of road traffic (very high and absent but all characterized by the presence of the same plant species, were selected. The pollen of herbaceous spontaneous species, arboreal species and a shrub species was used (Robinia pseudacacia, Aesculus x carnea, Catalpa bignonioides, Albizzia julibrissin, Rosa canina, Sambucus nigra, Malva neglecta, Ranunculus acer, Trifolium repens, Cichorium intybus. The pollen of these species was treated with TTC (2, 3, 5 Tryphenil-Tetrazolium-Chloride staining solution and viability was then estimated by light microscopy. The results of the mean pollen viability percentage of the examined species are reported. Pollen viability of herbaceous plants is significantly different between the two environments.

Viability of dielectrophoretically trapped neuronal cortical cells in culture

NARCIS (Netherlands)

Heida, Tjitske; Vulto, P; Rutten, Wim; Marani, Enrico

2001-01-01

Negative dielectrophoretic trapping of neural cells is an efficient way to position neural cells on the electrode sites of planar micro-electrode arrays. The preservation of viability of the neural cells is essential for this approach. This study investigates the viability of postnatal cortical rat

Flow cytometric assessment of viability of lactic acid bacteria

NARCIS (Netherlands)

Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F.M.; Abee, T.

2001-01-01

The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA

Sperm viability staining in ecology and evolution: potential pitfalls

DEFF Research Database (Denmark)

Holman, Luke

2009-01-01

The causes and consequences of variation in sperm quality, survival and ageing are active areas of research in ecology and evolution. In order to address these topics, many recent studies have measured sperm viability using fluorescent staining. Although sperm viability staining has produced a nu...

Localization and expression of clarin-1, the Clrn1 gene product, in auditory hair cells and photoreceptors

Science.gov (United States)

Zallocchi, Marisa; Meehan, Daniel T.; Delimont, Duane; Askew, Charles; Garrige, Suneetha; Gratton, Michael Anne; Rothermund-Franklin, Christie A.; Cosgrove, Dominic

2009-01-01

The Usher syndrome 3A (CLRN1) gene encodes clarin-1, which is a member of the tetraspanin family of transmembrane proteins. Although identified more than 6 years ago, little is known about its localization or function in the eye and ear. We developed a polyclonal antibody that react with all clarin-1 isoforms and used it to characterize protein expression in cochlea and retina. In the cochlea, we observe clarin-1expression in the stereocilia of P0 mice, and in synaptic terminals present at the base of the auditory hair cells from E18 to P6. In the retina, clarin-1 localizes to the connecting cilia, inner segment of photoreceptors and to the ribbon synapses. RT-PCR from P0 cochlea and P28 retina show mRNAs encoding only isoforms 2 and 3. Western-blots show that only isoform 2 is present in protein extracts from these same tissues. We examined clarin-1 expression in the immortomouse-derived hair cell line UB/OC-1. Only isoform 2 is expressed in UB/OC-1 at both mRNA and protein levels, suggesting this isoform is biologically relevant to hair cell function. The protein co-localizes with microtubules and post-transgolgi vesicles. The sub-cellular localization of clarin-1 in hair cells and photoreceptors suggests it functions at both the basal and apical poles of neurosensoriepithelia. PMID:19539019

Pollen viability and germination in Jatropha ribifolia and Jatropha ...

African Journals Online (AJOL)

The aim of this work is to assess pollen viability using the staining technique and in vitro germination with different concentrations of sucrose in Jatropha ribifolia and Jatropha mollissima, contributing to the knowledge of the reproductive biology and subsidizing their conservation, management and utilization. Pollen viability ...

Modeling the Flexural Rigidity of Rod Photoreceptors

Science.gov (United States)

Haeri, Mohammad; Knox, Barry E.; Ahmadi, Aphrodite

2013-01-01

In vertebrate eyes, the rod photoreceptor has a modified cilium with an extended cylindrical structure specialized for phototransduction called the outer segment (OS). The OS has numerous stacked membrane disks and can bend or break when subjected to mechanical forces. The OS exhibits axial structural variation, with extended bands composed of a few hundred membrane disks whose thickness is diurnally modulated. Using high-resolution confocal microscopy, we have observed OS flexing and disruption in live transgenic Xenopus rods. Based on the experimental observations, we introduce a coarse-grained model of OS mechanical rigidity using elasticity theory, representing the axial OS banding explicitly via a spring-bead model. We calculate a bending stiffness of ∼105 nN⋅μm2, which is seven orders-of-magnitude larger than that of typical cilia and flagella. This bending stiffness has a quadratic relation to OS radius, so that thinner OS have lower fragility. Furthermore, we find that increasing the spatial frequency of axial OS banding decreases OS rigidity, reducing its fragility. Moreover, the model predicts a tendency for OS to break in bands with higher spring number density, analogous to the experimental observation that transgenic rods tended to break preferentially in bands of high fluorescence. We discuss how pathological alterations of disk membrane properties by mutant proteins may lead to increased OS rigidity and thus increased breakage, ultimately contributing to retinal degeneration. PMID:23442852

Viability of mesenchymal stem cells during electrospinning

Directory of Open Access Journals (Sweden)

G. Zanatta

2012-02-01

Full Text Available Tissue engineering is a technique by which a live tissue can be re-constructed and one of its main goals is to associate cells with biomaterials. Electrospinning is a technique that facilitates the production of nanofibers and is commonly used to develop fibrous scaffolds to be used in tissue engineering. In the present study, a different approach for cell incorporation into fibrous scaffolds was tested. Mesenchymal stem cells were extracted from the wall of the umbilical cord and mononuclear cells from umbilical cord blood. Cells were re-suspended in a 10% polyvinyl alcohol solution and subjected to electrospinning for 30 min under a voltage of 21 kV. Cell viability was assessed before and after the procedure by exclusion of dead cells using trypan blue staining. Fiber diameter was observed by scanning electron microscopy and the presence of cells within the scaffolds was analyzed by confocal laser scanning microscopy. After electrospinning, the viability of mesenchymal stem cells was reduced from 88 to 19.6% and the viability of mononuclear cells from 99 to 8.38%. The loss of viability was possibly due to the high viscosity of the polymer solution, which reduced the access to nutrients associated with electric and mechanical stress during electrospinning. These results suggest that the incorporation of cells during fiber formation by electrospinning is a viable process that needs more investigation in order to find ways to protect cells from damage.

Images of photoreceptors in living primate eyes using adaptive optics two-photon ophthalmoscopy

Science.gov (United States)

Hunter, Jennifer J.; Masella, Benjamin; Dubra, Alfredo; Sharma, Robin; Yin, Lu; Merigan, William H.; Palczewska, Grazyna; Palczewski, Krzysztof; Williams, David R.

2011-01-01

In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images of the macaque cone mosaic were obtained using a fluorescence adaptive optics scanning laser ophthalmoscope, overcoming the challenges of a low numerical aperture, imperfect optics of the eye, high required light levels, and eye motion. Although the specific fluorophores are as yet unknown, strong in vivo intrinsic fluorescence allowed images of the cone mosaic. Imaging intact ex vivo retina revealed that the strongest two-photon excited fluorescence signal comes from the cone inner segments. The fluorescence response increased following light stimulation, which could provide a functional measure of the effects of light on photoreceptors. PMID:21326644

Pollen diversity, viability and floral structure of some Musa genotypes

African Journals Online (AJOL)

Pollen diversity, viability and floral structure of some Musa genotypes. ... This experiment was designed to study the floral structure, pollen morphology and the potential pollen viability of five Musa genotypes obtained ... HOW TO USE AJOL.

Efficacy of 670 nm Light Therapy to Protect against Photoreceptor Cell Death Is Dependent on the Severity of Damage

Directory of Open Access Journals (Sweden)

Joshua A. Chu-Tan

2016-01-01

Full Text Available Photobiomodulation at a wavelength of 670 nm has been shown to be effective in preventing photoreceptor cell death in the retina. We treated Sprague-Dawley (SD rats with varying doses of 670 nm light (9; 18; 36; 90 J/cm2 before exposing them to different intensities of damaging white light (750; 1000; 1500 lux. 670 nm light exhibited a biphasic response in its amelioration of cell death in light-induced degeneration in vivo. Lower light damage intensities required lower doses of 670 nm light to reduce TUNEL cell death. At higher damage intensities, the highest dose of 670 nm light showed protection. In vitro, the Seahorse XFe96 Extracellular Flux Analyzer revealed that 670 nm light directly influences mitochondrial metabolism by increasing the spare respiratory capacity of mitochondria in 661 W photoreceptor-like cells in light damaged conditions. Our findings further support the use of 670 nm light as an effective treatment against retinal degeneration as well as shedding light on the mechanism of protection through the increase of the mitochondrial spare respiratory capacity.

Loss-of-function of the ciliopathy protein Cc2d2a disorganizes the vesicle fusion machinery at the periciliary membrane and indirectly affects Rab8-trafficking in zebrafish photoreceptors.

Science.gov (United States)

Ojeda Naharros, Irene; Gesemann, Matthias; Mateos, José M; Barmettler, Gery; Forbes, Austin; Ziegler, Urs; Neuhauss, Stephan C F; Bachmann-Gagescu, Ruxandra

2017-12-01

Ciliopathies are human disorders caused by dysfunction of primary cilia, ubiquitous organelles involved in transduction of environmental signals such as light sensation in photoreceptors. Concentration of signal detection proteins such as opsins in the ciliary membrane is achieved by RabGTPase-regulated polarized vesicle trafficking and by a selective barrier at the ciliary base, the transition zone (TZ). Dysfunction of the TZ protein CC2D2A causes Joubert/Meckel syndromes in humans and loss of ciliary protein localization in animal models, including opsins in retinal photoreceptors. The link between the TZ and upstream vesicle trafficking has been little explored to date. Moreover, the role of the small GTPase Rab8 in opsin-carrier vesicle (OCV) trafficking has been recently questioned in a mouse model. Using correlative light and electron microscopy and live imaging in zebrafish photoreceptors, we provide the first live characterization of Rab8-mediated trafficking in photoreceptors in vivo. Our results support a possibly redundant role for both Rab8a/b paralogs in OCV trafficking, based on co-localization of Rab8 and opsins in vesicular structures, and joint movement of Rab8-tagged particles with opsin. We further investigate the role of the TZ protein Cc2d2a in Rab8-mediated trafficking using cc2d2a zebrafish mutants and identify a requirement for Cc2d2a in the latest step of OCV trafficking, namely vesicle fusion. Progressive accumulation of opsin-containing vesicles in the apical portion of photoreceptors lacking Cc2d2a is caused by disorganization of the vesicle fusion machinery at the periciliary membrane with mislocalization and loss of the t-SNAREs SNAP25 and Syntaxin3 and of the exocyst component Exoc4. We further observe secondary defects on upstream Rab8-trafficking with cytoplasmic accumulation of Rab8. Taken together, our results support participation of Rab8 in OCV trafficking and identify a novel role for the TZ protein Cc2d2a in fusion of incoming

Survey of the Definition of Fetal Viability and the Availability, Indications, and Decision Making Processes for Post-Viability Termination of Pregnancy for Fetal Abnormalities and Health Conditions in Canada.

Science.gov (United States)

Hull, Danna; Davies, Gregory; Armour, Christine M

2016-06-01

The purpose of this study was to explore the definition of fetal viability and the availability, indications, and decision making processes for post-viability termination of pregnancy for fetal abnormalities and health conditions in Canada. An online survey of members of the Canadian Association of Genetic Counsellors, the Canadian College of Medical Geneticists, and the Canadian Society for Maternal-Fetal Medicine who provide direct counselling to, or management of, prenatal patients in Canada (total sample size 815). Results of this study showed that the majority of respondents indicated that their centre will offer post-viability termination of pregnancy (98/123; 80 %). Sixty-seven percent (68/101) of respondents reported the definition of fetal viability to be 24 weeks' gestation. Most respondents reported that a collaborative decision making process was used to determine if post-viability termination of pregnancy would be offered (136/170; 80 %). For conditions presumed to be lethal/likely lethal, the majority of respondents would "sometimes" or "always" offer post-viability termination of pregnancy, whereas for conditions presumed to have a mild effect, the majority of respondents would "rarely" or "never" offer post-viability termination of pregnancy. Ninety percent (77/86) of respondents reported that perinatal hospice is offered as an alternative to termination of pregnancy. In conclusion, this study suggests that although post-viability termination is available in many provinces in Canada, variation in the definition of fetal viability and indications appear to exist. While these variations may lead to unequal access to post-viability termination of pregnancy across Canada, they might also represent the complexity of the decision making process and the importance of examining individual factors to ensure that the most appropriate decision is made in each case.

Normal central retinal function and structure preserved in retinitis pigmentosa.

Science.gov (United States)

Jacobson, Samuel G; Roman, Alejandro J; Aleman, Tomas S; Sumaroka, Alexander; Herrera, Waldo; Windsor, Elizabeth A M; Atkinson, Lori A; Schwartz, Sharon B; Steinberg, Janet D; Cideciyan, Artur V

2010-02-01

To determine whether normal function and structure, as recently found in forms of Usher syndrome, also occur in a population of patients with nonsyndromic retinitis pigmentosa (RP). Patients with simplex, multiplex, or autosomal recessive RP (n = 238; ages 9-82 years) were studied with static chromatic perimetry. A subset was evaluated with optical coherence tomography (OCT). Co-localized visual sensitivity and photoreceptor nuclear layer thickness were measured across the central retina to establish the relationship of function and structure. Comparisons were made to patients with Usher syndrome (n = 83, ages 10-69 years). Cross-sectional psychophysical data identified patients with RP who had normal rod- and cone-mediated function in the central retina. There were two other patterns with greater dysfunction, and longitudinal data confirmed that progression can occur from normal rod and cone function to cone-only central islands. The retinal extent of normal laminar architecture by OCT corresponded to the extent of normal visual function in patients with RP. Central retinal preservation of normal function and structure did not show a relationship with age or retained peripheral function. Usher syndrome results were like those in nonsyndromic RP. Regional disease variation is a well-known finding in RP. Unexpected was the observation that patients with presumed recessive RP can have regions with functionally and structurally normal retina. Such patients will require special consideration in future clinical trials of either focal or systemic treatment. Whether there is a common molecular mechanism shared by forms of RP with normal regions of retina warrants further study.

An updated methodology to review developing-country vaccine manufacturer viability.

Science.gov (United States)

Luter, Nicholas; Kumar, Ritu; Hozumi, Dai; Lorenson, Tina; Larsen, Shannon; Gowda, Bhavya; Batson, Amie

2017-07-05

In 1997, Milstien, Batson, and Meaney published "A Systematic Method for Evaluating the Potential Viability of Local Vaccine Producers." The paper identified characteristics of successful vaccine manufacturers and developed a viability framework to evaluate their performance. This paper revisits the original study after two decades to determine the ability of the framework to predict manufacturer success. By reconstructing much of the original dataset and conducting in-depth interviews, the authors developed informed views on the continued viability of manufacturers in low- and middle-income country markets. Considering the marked changes in the market and technology landscape since 1997, the authors find the viability framework to be predictive and a useful lens through which to evaluate manufacturer success or failure. Of particular interest is how incumbent and potentially new developing-country vaccine manufacturers enter and sustain production in competitive international markets and how they integrate (or fail to integrate) new technology into the production process. Ultimately, most manufacturers will need to meet global quality standards to be viable. As governments and donors consider investments in vaccine producers, the updated viability factors will be a useful tool in evaluating the prospects of manufacturers over the mid to long term. The paper emphasizes that while up-front investments are important, other critical factors-including investments in a national regulatory authority, manufacturer independence, and ability to adapt and adopt new technology-are necessary to ensure viability. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

PBMC and MDAMB-231 cellular viability after telecobalt irradiation

International Nuclear Information System (INIS)

Andrade, Lidia M.; Campos, Tarcisio P.R.

2002-01-01

Radiotherapy by gamma rays are used for cancer treatment. Ionizing radiation effects on cells has been investigated. Studies in vitro were developed using tumor cell lines and ionizing radiation. The aim of this research was to test the cellular viability response of two cell types through MTT assay: human peripheral blood mononuclear cell (PBMC) and human breast carcinoma cell line MDAMB-231. These cells were irradiated with 60 Co source Theratron 80 radiotherapy machine from Atomic Energy Canada Limited with 20 x 20 cm field at 136.4 cGy/min, surface source distance 70 cm. Culture flasks contained 10 4 , 10 5 and 10 6 cells were irradiated with 100 Gy, 25 Gy, and 50 Gy using non fractionated doses. Cellular viability were evaluated 1h, 24h, 48h and 72h after irradiation and samples were measured by optical density at 595nm. Our results show that PBMC cells present lower cellular viability post irradiation. On the other hand, MDAMB-231 cells maintain viability after 50 Gy irradiation at 72h indicating cellular radioresistance. (author)

Viability of seeds of two representatives from Apocynaceae family

Directory of Open Access Journals (Sweden)

Y.A. Aviekin

2015-05-01

Full Text Available The viability of some Apocynaceae seeds depending on the duration of storage under conditions of low temperature was studied. Extracted embryos from the seeds of Pachypodium lamerei Drake and Adenium obesum (Forssk. Roem. et Schult with different storage history were analyzed. Embryos were stained by acidic fuchsine what allows identification of viable and destructed cells. Destructed cells were stained much more intensively, while viable cells remained unstained. Observed results showed dependence of viability of P. lamerei and A. obesum seeds from term of storage. It was obtained that the seeds of investigated succulent species, just like in many other tropical plants, rapidly lost their viability and should be described as microbiotic.

Circadian locomotor rhythms in the cricket, Gryllodes sigillatus. I. Localization of the pacemaker and the photoreceptor.

Science.gov (United States)

Abe, Y; Ushirogawa, H; Tomioka, K

1997-10-01

Circadian locomotor rhythm and its underlying mechanism were investigated in the cricket, Gryllodes sigillatus. Adult male crickets showed a nocturnal locomotor rhythm peaking early in the dark phase of a light to dark cycle. This rhythm persisted under constant darkness (DD) with a free-running period averaging 23.1 +/- 0.3 hr. Although constant bright light made most animals arrhythmic, about 40% of the animals showed free-running rhythms with a period longer than 24 hr under constant dim light condition. On transfer to DD, all arrhythmic animals restored the locomotor rhythm. Bilateral optic nerve severance resulted in free-running of the rhythm even under light-dark cycles. The free-running period of the optic nerve severed animals was significantly longer than sham operated crickets in DD, suggesting that the compound eye plays some role in determining the free-running period. Removal of bilateral lamina-medulla portion of the optic lobe abolished the rhythm under DD. These results demonstrate that the photoreceptor for entrainment is the compound eye and the optic lobe is indispensable for persistence of the rhythm. However, 75% and 54% of the optic lobeless animals showed aberrant rhythms with a period very close to 24 hr under light and temperature cycles, respectively, suggesting that there are neural and/or humoral mechanisms for the aberrant rhythms outside of the optic lobe. Since ocelli removal did not affect the photoperiodically induced rhythm, it is likely that the photoreception for the rhythm is performed through an extraretinal photoreceptor.

Transplantation of adult mouse iPS cell-derived photoreceptor precursors restores retinal structure and function in degenerative mice.

Directory of Open Access Journals (Sweden)

Budd A Tucker

2011-04-01

Full Text Available This study was designed to determine whether adult mouse induced pluripotent stem cells (iPSCs, could be used to produce retinal precursors and subsequently photoreceptor cells for retinal transplantation to restore retinal function in degenerative hosts. iPSCs were generated using adult dsRed mouse dermal fibroblasts via retroviral induction of the transcription factors Oct4, Sox2, KLF4 and c-Myc. As with normal mouse ES cells, adult dsRed iPSCs expressed the pluripotency genes SSEA1, Oct4, Sox2, KLF4, c-Myc and Nanog. Following transplantation into the eye of immune-compromised retinal degenerative mice these cells proceeded to form teratomas containing tissue comprising all three germ layers. At 33 days post-differentiation a large proportion of the cells expressed the retinal progenitor cell marker Pax6 and went on to express the photoreceptor markers, CRX, recoverin, and rhodopsin. When tested using calcium imaging these cells were shown to exhibit characteristics of normal retinal physiology, responding to delivery of neurotransmitters. Following subretinal transplantation into degenerative hosts differentiated iPSCs took up residence in the retinal outer nuclear layer and gave rise to increased electro retinal function as determined by ERG and functional anatomy. As such, adult fibroblast-derived iPSCs provide a viable source for the production of retinal precursors to be used for transplantation and treatment of retinal degenerative disease.

Drosophila photoreceptor axon guidance and targeting requires the dreadlocks SH2/SH3 adapter protein.

Science.gov (United States)

Garrity, P A; Rao, Y; Salecker, I; McGlade, J; Pawson, T; Zipursky, S L

1996-05-31

Mutations in the Drosophila gene dreadlocks (dock) disrupt photoreceptor cell (R cell) axon guidance and targeting. Genetic mosaic analysis and cell-type-specific expression of dock transgenes demonstrate dock is required in R cells for proper innervation. Dock protein contains one SH2 and three SH3 domains, implicating it in tyrosine kinase signaling, and is highly related to the human proto-oncogene Nck. Dock expression is detected in R cell growth cones in the target region. We propose Dock transmits signals in the growth cone in response to guidance and targeting cues. These findings provide an important step for dissection of signaling pathways regulating growth cone motility.

Viability Test Device for anisakid nematodes

Directory of Open Access Journals (Sweden)

Michael Kroeger

2018-03-01

Full Text Available Up to now the visual inspection of mobility of isolated anisakid larvae serves as a measure of viability and possible risk of infection. This paper presents a new method to rule out unreliability – caused by the temporary immobility of the larvae and by the human uncertainty factor of visual observation. By means of a Near infrared (NIR imaging method, elastic curvature energies and geometric shape parameters were determined from contours, and used as a measure of viability. It was based on the modelling of larvae as a cylindrical membrane system. The interaction between curvatures, contraction of the longitudinal muscles, and inner pressure enabled the derivation of viability from stationary form data. From series of spectrally signed images within a narrow wavelength range, curvature data of the larvae were determined. Possible mobility of larvae was taken into account in statistical error variables. Experiments on individual living larvae, long-term observations of Anisakis larvae, and comparative studies of the staining method and the VTD measurements of larvae from the tissue of products confirmed the effectiveness of this method. The VTD differentiated clearly between live and dead nematode larvae isolated from marinated, deep-frozen and salted products. The VTD has been proven as excellent method to detect living anisakid nematode larvae in fishery products and is seen as useful tool for fish processing industry and control authorities. Keywords: Biophysics

Independent signaling by Drosophila insulin receptor for axon guidance and growth

Directory of Open Access Journals (Sweden)

Caroline Rita Li

2014-01-01

Full Text Available The Drosophila insulin receptor (DInR regulates a diverse array of biological processes including growth, axon guidance, and sugar homeostasis. Growth regulation by DInR is mediated by Chico, the Drosophila homolog of vertebrate insulin-receptor-substrate proteins IRS1-4. In contrast, DInR regulation of photoreceptor axon guidance in the developing visual system is mediated by the SH2-SH3 domain adaptor protein Dreadlocks (Dock. In vitro studies by others identified five NPXY motifs, one in the juxtamembrane region and four in the signaling C-terminal tail (C-tail, important for interaction with Chico. Here we used yeast two-hybrid assays to identify regions in the DInR C-tail that interact with Dock. These Dock-binding sites were in separate portions of the C-tail from the previously identified Chico-binding sites. To test whether these sites are required for growth or axon guidance in whole animals, a panel of DInR proteins, in which the putative Chico and Dock interaction sites had been mutated individually or in combination, were tested for their ability to rescue viability, growth, and axon guidance defects of dinr mutant flies. Sites required for viability were identified. Unexpectedly, mutation of both putative Dock binding sites, either individually or in combination, did not lead to defects in photoreceptor axon guidance. Thus, either sites also required for viability are necessary for DInR function in axon guidance and/or there is redundancy built into the DInR/Dock interaction such that Dock is able to interact with multiple regions of DInR. We also found that simultaneous mutation of all 5 NPXY motifs implicated in Chico interaction drastically decreased growth in both male and female adult flies. Mutation of these 5 NPXY motifs did not affect photoreceptor axon guidance, showing that different sites within DInR control growth and axon guidance.

Extreme-Dipper Profile, Increased Aortic Stiffness, and Impaired Subendocardial Viability in Hypertension.

Science.gov (United States)

Amah, Guy; Ouardani, Rahma; Pasteur-Rousseau, Adrien; Voicu, Sebastian; Safar, Michel E; Kubis, Nathalie; Bonnin, Philippe

2017-04-01

In treated hypertensives, extreme-dippers with stable coronary artery disease (CAD) exhibit more severe nighttime cardiac ischemia than dippers. After excluding confounding factors such as diabetes, CAD or chronic kidney disease (CKD), we assessed whether subendocardial viability, determined by the Buckberg index, was more significantly impaired in extreme-dippers than in dippers. Two hundred thirteen consecutive treated hypertensives (156 dippers, 57 extreme-dippers), were included. After 24-hour ambulatory blood pressure (BP) monitoring, patients underwent radial applanation tonometry (with determination of: subendocardial viability ratio [SEVR], central augmentation index [AIx], and pulse pressure amplification [PPamp]), carotid-femoral pulse wave velocity (cfPWV) measurement, and cycle ergometer stress testing. Extreme-dippers showed higher cfPWV (8.99 ± 2.16 vs. 8.29 ± 1.69 m/s, P = 0.014), higher AIx (29.7 ± 9.4 vs. 26.4 ± 10.4%, P = 0.042), lower PPamp (1.22 ± 0.14 vs. 1.30 ± 0.15, P < 0.001), lower SEVR (146 ± 23% vs. 157 ± 26%, P = 0.007), and lower nighttime diastolic BP (DBP) (70 ± 9 vs. 75 ± 9 mm Hg, P < 0.001) than dippers. SEVR and cfPWV were inversely correlated. Among extreme-dippers, women exhibited lower SEVR (138 ± 21% vs. 161 ± 23%, P = 0.004), PPamp (1.16 ± 0.10 vs. 1.31 ± 0.15, P < 0.001), and nighttime DBP (67 ± 8 mm Hg vs. 72 ± 8 mm Hg, P = 0.017) than men. Extreme-dipper treated hypertensives with no history of CAD, diabetes or CKD, present increased aortic stiffness and low PPamp. Furthermore, this is the first demonstration of the greater likelihood of these patients to exhibit impaired subendocardial viability compared to dippers. Extreme-dipper hypertensive patients, women in particular, may have a significantly higher risk of silent myocardial ischemia, thus justifying systematic screening. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Identification of intracellular phospholipases A2 in the human eye: involvement in phagocytosis of photoreceptor outer segments

DEFF Research Database (Denmark)

Kolko, Miriam; Wang, Jinmei; Zhan, Chen

2007-01-01

PURPOSE: To identify intracellular phospholipases A(2) (PLA(2)) in the human retina and to explore the role of these enzymes in human retinal pigment epithelium (RPE) phagocytosis of photoreceptor outer segments (POS). METHODS: PCR amplification and Western blot analysis were used to identify m......)-VIA activity was found to be specifically increased 12 hours after ARPE-19 cells were fed with POS. Finally, RPE phagocytosis was inhibited by the iPLA(2)-VIA inhibitor bromoenol lactone. CONCLUSIONS: Various intracellular PLA(2) subtypes are present in the human retina. iPLA(2)-VIA may play...

Detecting viability transitions of umbilical cord mesenchymal stem cells by Raman micro-spectroscopy

International Nuclear Information System (INIS)

Bai, H; Chen, P; Fang, H; Lin, L; Tang, G Q; Mu, G G; Gong, W; Liu, Z P; Wu, H; Zhao, H; Han, Z C

2011-01-01

Recent research suggests that human umbilical cord derived mesenchymal stem cells (hUC-MSCs) can be promising candidates for cell-based therapy. Since large population and high viability are generally required, detecting viability transitions of these cells is crucial for their population expansion and quality control. Here, as a non-invasive method, Raman micro-spectroscopy is applied to examine hUC-MSCs with different viability. Using peak fitting and statistic t-test, the Raman peaks with obvious differences between the cells with high viability (> 90%) and low viability ( -1 , symmetric stretching of C–C in lipids at 877 cm -1 and CH deformation in proteins at 1342 cm -1 show the most significant changes (p < 0.001). When the cell viability decreases, the intensities of the former two peaks are both about doubled while that of the latter peak reduces by about 30%. Based on these results, we propose that the viability of hUC-MSCs can be characterized by these three peaks. And their intensity changes can be understood from the model of excessive reactive oxygen species interacting with the bio-macromolecules

Nuclear architecture of rod photoreceptor cells adapts to vision in mammalian evolution.

Science.gov (United States)

Solovei, Irina; Kreysing, Moritz; Lanctôt, Christian; Kösem, Süleyman; Peichl, Leo; Cremer, Thomas; Guck, Jochen; Joffe, Boris

2009-04-17

We show that the nuclear architecture of rod photoreceptor cells differs fundamentally in nocturnal and diurnal mammals. The rods of diurnal retinas possess the conventional architecture found in nearly all eukaryotic cells, with most heterochromatin situated at the nuclear periphery and euchromatin residing toward the nuclear interior. The rods of nocturnal retinas have a unique inverted pattern, where heterochromatin localizes in the nuclear center, whereas euchromatin, as well as nascent transcripts and splicing machinery, line the nuclear border. The inverted pattern forms by remodeling of the conventional one during terminal differentiation of rods. The inverted rod nuclei act as collecting lenses, and computer simulations indicate that columns of such nuclei channel light efficiently toward the light-sensing rod outer segments. Comparison of the two patterns suggests that the conventional architecture prevails in eukaryotic nuclei because it results in more flexible chromosome arrangements, facilitating positional regulation of nuclear functions.

Morphology and viability of castor bean genotypes pollen grains

Directory of Open Access Journals (Sweden)

Maria Selma Alves Silva Diamantino

2016-01-01

Full Text Available The objective of this work was to characterize the morphology and viability of the pollen of 15 genotypes of castor bean (Ricinus communis L. and to generate information that can assist in the selection of highly promising male parents for future use in genetic improvement programs aimed at producing seeds for oil extraction. Acetolysis and scanning electron microscopy was used to characterize the morphology of the pollen. The viability of the pollen grains was estimated by in vitro germination and colorimetric analysis (acetocarmine 2% and 2, 3, 5-triphenyltetrazolium chloride 1%. For the in vitro germination, pollen grains were grown in 10 types of solidified culture medium consisting of different concentrations of sucrose, boric acid, calcium nitrate, magnesium sulfate and potassium nitrate. The pollen grains had the following characteristics: medium size, isopolar and subspheroidal shape, radial symmetry, circular ambit, 3-colporate, elongated endoapertures, tectate exine and granulated sexine. The acetocarmine dye overestimated pollen viability. The media M5 and M8 were the most efficient at promoting the germination of pollen grains. The studied genotypes had high levels of viability and can therefore be used as male parents in genetic improvement programs.

Preservation of seed viability during 25 years of storage under standard genebank conditions

NARCIS (Netherlands)

Treuren, van R.; Groot, de E.C.; Hintum, van T.J.L.

2013-01-01

Maintaining sufficient viability is critical to the sustainability of ex situ conserved seed collections. For this reason, accessions are regenerated when viability falls below a predefined threshold. Viability is monitored by determining the germination ability of accessions at predefined time

Effect of Chlorine on Giardia lamblia Cyst Viability

OpenAIRE

Jarroll, Edward L.; Bingham, Alan K.; Meyer, Ernest A.

1981-01-01

The effect of chlorine concentration on Giardia lamblia cyst viability was tested under a variety of conditions. The ability of Giardia cysts to undergo excystation was used as the criterion of viability. The experimental variables employed included temperature (25, 15, and 5°C), pH (6, 7, and 8), chlorine-cyst contact time (10, 30, and 60 min), and chlorine concentration (1 to 8 mg/liter). In the pH range studied, cyst survival generally was observed to increase as buffer pH increased. Water...

Mutually exclusive expression of human red and green visual pigment-reporter transgenes occurs at high frequency in murine cone photoreceptors.

Science.gov (United States)

Wang, Y; Smallwood, P M; Cowan, M; Blesh, D; Lawler, A; Nathans, J

1999-04-27

This study examines the mechanism of mutually exclusive expression of the human X-linked red and green visual pigment genes in their respective cone photoreceptors by asking whether this expression pattern can be produced in a mammal that normally carries only a single X-linked visual pigment gene. To address this question, we generated transgenic mice that carry a single copy of a minimal human X chromosome visual pigment gene array in which the red and green pigment gene transcription units were replaced, respectively, by alkaline phosphatase and beta-galactosidase reporters. As determined by histochemical staining, the reporters are expressed exclusively in cone photoreceptor cells. In 20 transgenic mice carrying any one of three independent transgene insertion events, an average of 63% of expressing cones have alkaline phosphatase activity, 10% have beta-galactosidase activity, and 27% have activity for both reporters. Thus, mutually exclusive expression of red and green pigment transgenes can be achieved in a large fraction of cones in a dichromat mammal, suggesting a facile evolutionary path for the development of trichromacy after visual pigment gene duplication. These observations are consistent with a model of visual pigment expression in which stochastic pairing occurs between a locus control region and either the red or the green pigment gene promotor.

Role of the mouse retinal photoreceptor ribbon synapse in visual motion processing for optokinetic responses.

Science.gov (United States)

Sugita, Yuko; Araki, Fumiyuki; Chaya, Taro; Kawano, Kenji; Furukawa, Takahisa; Miura, Kenichiro

2015-01-01

The ribbon synapse is a specialized synaptic structure in the retinal outer plexiform layer where visual signals are transmitted from photoreceptors to the bipolar and horizontal cells. This structure is considered important in high-efficiency signal transmission; however, its role in visual signal processing is unclear. In order to understand its role in visual processing, the present study utilized Pikachurin-null mutant mice that show improper formation of the photoreceptor ribbon synapse. We examined the initial and late phases of the optokinetic responses (OKRs). The initial phase was examined by measuring the open-loop eye velocity of the OKRs to sinusoidal grating patterns of various spatial frequencies moving at various temporal frequencies for 0.5 s. The mutant mice showed significant initial OKRs with a spatiotemporal frequency tuning (spatial frequency, 0.09 ± 0.01 cycles/°; temporal frequency, 1.87 ± 0.12 Hz) that was slightly different from the wild-type mice (spatial frequency, 0.11 ± 0.01 cycles/°; temporal frequency, 1.66 ± 0.12 Hz). The late phase of the OKRs was examined by measuring the slow phase eye velocity of the optokinetic nystagmus induced by the sinusoidal gratings of various spatiotemporal frequencies moving for 30 s. We found that the optimal spatial and temporal frequencies of the mutant mice (spatial frequency, 0.11 ± 0.02 cycles/°; temporal frequency, 0.81 ± 0.24 Hz) were both lower than those in the wild-type mice (spatial frequency, 0.15 ± 0.02 cycles/°; temporal frequency, 1.93 ± 0.62 Hz). These results suggest that the ribbon synapse modulates the spatiotemporal frequency tuning of visual processing along the ON pathway by which the late phase of OKRs is mediated.

Role of the mouse retinal photoreceptor ribbon synapse in visual motion processing for optokinetic responses.

Directory of Open Access Journals (Sweden)

Yuko Sugita

Full Text Available The ribbon synapse is a specialized synaptic structure in the retinal outer plexiform layer where visual signals are transmitted from photoreceptors to the bipolar and horizontal cells. This structure is considered important in high-efficiency signal transmission; however, its role in visual signal processing is unclear. In order to understand its role in visual processing, the present study utilized Pikachurin-null mutant mice that show improper formation of the photoreceptor ribbon synapse. We examined the initial and late phases of the optokinetic responses (OKRs. The initial phase was examined by measuring the open-loop eye velocity of the OKRs to sinusoidal grating patterns of various spatial frequencies moving at various temporal frequencies for 0.5 s. The mutant mice showed significant initial OKRs with a spatiotemporal frequency tuning (spatial frequency, 0.09 ± 0.01 cycles/°; temporal frequency, 1.87 ± 0.12 Hz that was slightly different from the wild-type mice (spatial frequency, 0.11 ± 0.01 cycles/°; temporal frequency, 1.66 ± 0.12 Hz. The late phase of the OKRs was examined by measuring the slow phase eye velocity of the optokinetic nystagmus induced by the sinusoidal gratings of various spatiotemporal frequencies moving for 30 s. We found that the optimal spatial and temporal frequencies of the mutant mice (spatial frequency, 0.11 ± 0.02 cycles/°; temporal frequency, 0.81 ± 0.24 Hz were both lower than those in the wild-type mice (spatial frequency, 0.15 ± 0.02 cycles/°; temporal frequency, 1.93 ± 0.62 Hz. These results suggest that the ribbon synapse modulates the spatiotemporal frequency tuning of visual processing along the ON pathway by which the late phase of OKRs is mediated.

Noninvasive Real-Time Assessment of Cell Viability in a Three-Dimensional Tissue.

Science.gov (United States)

Mahfouzi, Seyed Hossein; Amoabediny, Ghassem; Doryab, Ali; Safiabadi-Tali, Seyed Hamid; Ghanei, Mostafa

2018-04-01

Maintaining cell viability within 3D tissue engineering scaffolds is an essential step toward a functional tissue or organ. Assessment of cell viability in 3D scaffolds is necessary to control and optimize tissue culture process. Monitoring systems based on respiration activity of cells (e.g., oxygen consumption) have been used in various cell cultures. In this research, an online monitoring system based on respiration activity was developed to monitor cell viability within acellular lung scaffolds. First, acellular lung scaffolds were recellularized with human umbilical cord vein endothelial cells, and then, cell viability was monitored during a 5-day period. The real-time monitoring system generated a cell growth profile representing invaluable information on cell viability and proliferative states during the culture period. The cell growth profile obtained by the monitoring system was consistent with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis and glucose consumption measurement. This system provided a means for noninvasive, real-time, and repetitive investigation of cell viability. Also, we showed the applicability of this monitoring system by introducing shaking as an operating parameter in a long-term culture.

Kaempferol nanoparticles achieve strong and selective inhibition of ovarian cancer cell viability

Science.gov (United States)

Luo, Haitao; Jiang, Bingbing; Li, Bingyun; Li, Zhaoliang; Jiang, Bing-Hua; Chen, Yi Charlie

2012-01-01

Ovarian cancer is one of the leading causes of cancer death for women throughout the Western world. Kaempferol, a natural flavonoid, has shown promise in the chemoprevention of ovarian cancer. A common concern about using dietary supplements for chemoprevention is their bioavailability. Nanoparticles have shown promise in increasing the bioavailability of some chemicals. Here we developed five different types of nanoparticles incorporating kaempferol and tested their efficacy in the inhibition of viability of cancerous and normal ovarian cells. We found that positively charged nanoparticle formulations did not lead to a significant reduction in cancer cell viability, whereas nonionic polymeric nanoparticles resulted in enhanced reduction of cancer cell viability. Among the nonionic polymeric nanoparticles, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) nanoparticles incorporating kaempferol led to significant reduction in cell viability of both cancerous and normal cells. Poly(DL-lactic acid-co-glycolic acid) (PLGA) nanoparticles incorporating kaempferol resulted in enhanced reduction of cancer cell viability together with no significant reduction in cell viability of normal cells compared with kaempferol alone. Therefore, both PEO-PPO-PEO and PLGA nanoparticle formulations were effective in reducing cancer cell viability, while PLGA nanoparticles incorporating kaempferol had selective toxicity against cancer cells and normal cells. A PLGA nanoparticle formulation could be advantageous in the prevention and treatment of ovarian cancers. On the other hand, PEO-PPO-PEO nanoparticles incorporating kaempferol were more effective inhibitors of cancer cells, but they also significantly reduced the viability of normal cells. PEO-PPO-PEO nanoparticles incorporating kaempferol may be suitable as a cancer-targeting strategy, which could limit the effects of the nanoparticles on normal cells while retaining their potency against cancer cells. We

Norbixin Protects Retinal Pigmented Epithelium Cells and Photoreceptors against A2E-Mediated Phototoxicity In Vitro and In Vivo.

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Valérie Fontaine

Full Text Available The accumulation of N-retinylidene-N-retinylethanolamine (A2E, a toxic by-product of the visual pigment cycle in the retinal pigment epithelium (RPE is a major cause of visual impairment in the elderly. Photooxidation of A2E results in retinal pigment epithelium degeneration followed by that of associated photoreceptors. Present treatments rely on nutrient supplementation with antioxidants. 9'-cis-Norbixin (a natural diapocarotenoid, 97% purity was prepared from Bixa orellana seeds. It was first evaluated in primary cultures of porcine retinal pigment epithelium cells challenged with A2E and illuminated with blue light, and it provided an improved photo-protection as compared with lutein or zeaxanthin. In Abca4-/- Rdh8-/- mice (a model of dry AMD, intravitreally-injected norbixin maintained the electroretinogram and protected photoreceptors against light damage. In a standard rat blue-light model of photodamage, norbixin was at least equally as active as phenyl-N-tert-butylnitrone, a free radical spin-trap. Chronic experiments performed with Abca4-/- Rdh8-/- mice treated orally for 3 months with norbixin showed a reduced A2E accumulation in the retina. Norbixin appears promising for developing an oral treatment of macular degeneration. A drug candidate (BIO201 with 9'-cis-norbixin as the active principle ingredient is under development, and its potential will be assessed in a forthcoming clinical trial.

Space mutagenic effects on cistanche deserticola seed viability and parasitic condition

International Nuclear Information System (INIS)

Xu Rong; Zhou Feng; Yu Jing; Chen Jun; Sun Suqin; Liu Yougang; Liu Tongning

2009-01-01

The seeds of Cistanche deserticola which from a single plant with fine properties were carried to the space by the recoverable experiment satellite 'Shijian No.8'. After space loading, the seed viability and characters of infrared spectroscopy were analyzed and then planted to observe and investigate the variation and heredity. The results showed that compared to the control group, the seed viability and germination rate increased observably after space loading. As well, the plants grew much healthier at the seedling stage. The results indicated that space loading has obvious promote effects on the seed viability, germination rate and disease resistance of Cistanche deserticola. The analysis results of infrared spectroscopy showed the contents of protein and carbohydrate were increased distinctly and the contents of oil or fat reduced somewhat in the seeds after space loading. The intensity ratio between characteristic absorption peak of protein and characteristic absorption peak of fat (I 1625 /I 1745 ) were increased from 1.07 to 1.16, which could be related to the enhancement of seed viability and the reduction of germination restraint substances. It could be concluded that microgravity and intense radiation in the space caused seed viability and material metabolism change. (authors)

Relationship between humidity and influenza A viability in droplets and implications for influenza's seasonality.

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Wan Yang

Full Text Available Humidity has been associated with influenza's seasonality, but the mechanisms underlying the relationship remain unclear. There is no consistent explanation for influenza's transmission patterns that applies to both temperate and tropical regions. This study aimed to determine the relationship between ambient humidity and viability of the influenza A virus (IAV during transmission between hosts and to explain the mechanisms underlying it. We measured the viability of IAV in droplets consisting of various model media, chosen to isolate effects of salts and proteins found in respiratory fluid, and in human mucus, at relative humidities (RH ranging from 17% to 100%. In all media and mucus, viability was highest when RH was either close to 100% or below ∼50%. When RH decreased from 84% to 50%, the relationship between viability and RH depended on droplet composition: viability decreased in saline solutions, did not change significantly in solutions supplemented with proteins, and increased dramatically in mucus. Additionally, viral decay increased linearly with salt concentration in saline solutions but not when they were supplemented with proteins. There appear to be three regimes of IAV viability in droplets, defined by humidity: physiological conditions (∼100% RH with high viability, concentrated conditions (50% to near 100% RH with lower viability depending on the composition of media, and dry conditions (<50% RH with high viability. This paradigm could help resolve conflicting findings in the literature on the relationship between IAV viability in aerosols and humidity, and results in human mucus could help explain influenza's seasonality in different regions.

Population viability analysis on domestic horse breeds (Equus caballus)

DEFF Research Database (Denmark)

Thirstrup, Janne Pia; Bach, Lars; Loeschcke, Volker

2009-01-01

simulation package was used for the population viability analysis. First, we investigated the future viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the viability of these breeds. Third, we examined...... concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts...... the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third...

Turnover of Glycerolipid Metabolite Pool and Seed Viability

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Xiao-Long Hu

2018-05-01

Full Text Available Hydration–dehydration cycles can frequently cause stress to seeds, but can also be used to improve germination. However, the molecular basis of the stress caused is poorly understood. Herein, we examine the effects of hydration–dehydration cycles on seed viability and profile the membrane glycerolipid molecular species. We find that seed viability was not affected during the first two cycles, but significantly decreased as further cycles were applied, until all viability was lost. The abundances of seven glycerolipid classes increased and decreased through hydration and dehydration, respectively, but the phosphatidic acid and diacylglycerol abundances changed in the opposite sense, while total glycerolipid contents remained constant. This suggests that during hydration–dehydration cycles, turnover of glycerolipid metabolite pools take place, while no significant lipid synthesis or degradation is involved. As further hydration–dehydration cycles occurred, lipid unsaturation increased, plastidic lipids decreased, and phosphatidylserine acyl chains lengthened. The latter two could be lethal for seeds. Our findings reveal a novel model of membrane lipid changes, and provide new insights into the responses of seeds to hydration–dehydration cycles.

Ca-Lignosulphonate and sclerotial viability of Sclerotinia sclerotiorum

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MATTEO MONTANARI

2012-01-01

Full Text Available Lignosulphonates, low cost by-products of the pulping process, have shown suppressive effects against some diseases caused by soil-borne pathogens. In this study, the effect of 1.5% v/v calcium lignosulphonate (Ca-Ls amendment to two commercial potting mixes (peat + coconut fibres; PC; and municipal compost + peat + pumice; MCPP on the viability of Sclerotinia sclerotiorum sclerotia was investigated. Sclerotia were buried in the Ca-Ls amended substrates for 30 days. Non-amended PC and MCPP, sterile sand and sterile PC with and without Ca-Ls were used as controls. The viability of sclerotia recovered from PC and MCPP amended with Ca-Ls was reduced by 50 and 42% respectively compared to control treatments. Ca-Ls amendment decreased sclerotial viability by enhancing the activity of the indigenous mycoparasitic fungi, Fusarium oxysporum, Mucor spp. and Trichoderma spp. The biocontrol ability of Ca-Ls against sclerotia was due to the stimulation of microbial activity and is, therefore, strictly dependent on the microbial composition of the substrate.

Photoreceptor Differentiation following Transplantation of Allogeneic Retinal Progenitor Cells to the Dystrophic Rhodopsin Pro347Leu Transgenic Pig

DEFF Research Database (Denmark)

Klassen, H; Kiilgaard, Jens Folke; Warfvinge, K

2012-01-01

Purpose. Transplantation of stem, progenitor, or precursor cells has resulted in photoreceptor replacement and evidence of functional efficacy in rodent models of retinal degeneration. Ongoing work has been directed toward the replication of these results in a large animal model, namely, the pig....... Methods. Retinal progenitor cells were derived from the neural retina of GFP-transgenic pigs and transplanted to the subretinal space of rhodopsin Pro347Leu-transgenic allorecipients, in the early stage of the degeneration and the absence of immune suppression. Results. Results confirm the survival...

Molecular assays for determining Mycobacterium leprae viability in tissues of experimentally infected mice.

Science.gov (United States)

Davis, Grace L; Ray, Nashone A; Lahiri, Ramanuj; Gillis, Thomas P; Krahenbuhl, James L; Williams, Diana L; Adams, Linda B

2013-01-01

The inability of Mycobacterium leprae to grow on axenic media has necessitated specialized techniques in order to determine viability of this organism. The purpose of this study was to develop a simple and sensitive molecular assay for determining M. leprae viability directly from infected tissues. Two M. leprae-specific quantitative reverse transcription PCR (qRT-PCR) assays based on the expression levels of esxA, encoding the ESAT-6 protein, and hsp18, encoding the heat shock 18 kDa protein, were developed and tested using infected footpad (FP) tissues of both immunocompetent and immunocompromised (athymic nu/nu) mice. In addition, the ability of these assays to detect the effects of anti-leprosy drug treatment on M. leprae viability was determined using rifampin and rifapentine, each at 10 mg/kg for 1, 5, or 20 daily doses, in the athymic nu/nu FP model. Molecular enumeration (RLEP PCR) and viability determinations (qRT-PCR) were performed via Taqman methodology on DNA and RNA, respectively, purified from ethanol-fixed FP tissue and compared with conventional enumeration (microscopic counting of acid fast bacilli) and viability assays (radiorespirometry, viability staining) which utilized bacilli freshly harvested from the contralateral FP. Both molecular and conventional assays demonstrated growth and high viability of M. leprae in nu/nu FPs over a 4 month infection period. In contrast, viability was markedly decreased by 8 weeks in immunocompetent mice. Rifapentine significantly reduced bacterial viability after 5 treatments, whereas rifampin required up to 20 treatments for the same efficacy. Neither drug was effective after a single treatment. In addition, host gene expression was monitored with the same RNA preparations. hsp18 and esxA qRT-PCR are sensitive molecular indicators, reliably detecting viability of M. leprae in tissues without the need for bacterial isolation or immediate processing, making these assays applicable for in vivo drug screening and

The cybernetics of viability: an overview

Science.gov (United States)

Nechansky, Helmut

2011-10-01

A three-level approach to viability is developed, considering (1) living systems, (2) a niche, understood as the area within the reach of their actions, and (3) an environment. A systematic analysis of the interrelations between these levels shows that living systems emerge with matter/energy processing systems. These can add controller structures when producing excess energy. A three-sensor controller structure enables a living system to deal with unfavourable and scarce environments. Further evolution of these controller structures offers improved ways to act on niches. Maintaining niches in scarce environments can require technology or economy. So social systems emerge, which are understood as aggregates of living systems. Basic patterns of interactions within social systems are analysed. So the introduction of the notion of the niche into the discussion of viability allows us to explain phenomena ranging from properties of single living systems to societal organization.

A Classification Method for Seed Viability Assessment with Infrared Thermography

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Sen Men

2017-04-01

Full Text Available This paper presents a viability assessment method for Pisum sativum L. seeds based on the infrared thermography technique. In this work, different artificial treatments were conducted to prepare seeds samples with different viability. Thermal images and visible images were recorded every five minutes during the standard five day germination test. After the test, the root length of each sample was measured, which can be used as the viability index of that seed. Each individual seed area in the visible images was segmented with an edge detection method, and the average temperature of the corresponding area in the infrared images was calculated as the representative temperature for this seed at that time. The temperature curve of each seed during germination was plotted. Thirteen characteristic parameters extracted from the temperature curve were analyzed to show the difference of the temperature fluctuations between the seeds samples with different viability. With above parameters, support vector machine (SVM was used to classify the seed samples into three categories: viable, aged and dead according to the root length, the classification accuracy rate was 95%. On this basis, with the temperature data of only the first three hours during the germination, another SVM model was proposed to classify the seed samples, and the accuracy rate was about 91.67%. From these experimental results, it can be seen that infrared thermography can be applied for the prediction of seed viability, based on the SVM algorithm.

Economic Viability and Marketing Strategies of Periwinkle ...

African Journals Online (AJOL)

Economic Viability and Marketing Strategies of Periwinkle Tympanotonus Fuscatus in Rivers State, Nigeria. ... The results indicated that marketing strategies are enroute, through harvesters (collectors), ... EMAIL FULL TEXT EMAIL FULL TEXT

Challenge testing of gametes to enhance their viability

DEFF Research Database (Denmark)

Callesen, Henrik

2010-01-01

of survival mechanism that enables them to come through the process. The details of the mechanism remain unknown but, if identified, it could have immense potential as a new way to improve the viability of embryos produced by ART. However, few publications describe systematic ways to challenge test gametes...... and then to use the results as a basis for improving gamete viability. Furthermore, new methods to monitor the reactions of gametes to such challenge tests are needed. In the present review, these two issues are discussed, as are some of the conditions necessary before a challenge test protocol can be part...

Assessment of the technical viability of reactor options for plutonium disposition

International Nuclear Information System (INIS)

Primm, R.T. III.

1996-01-01

Various reactor concepts for the disposition of surplus Pu have been proposed by reactor vendors; not all have attained the same level of technical viability. Studies were performed to differentiate between reactor concepts by devising a quantitative index for technical viability. For a quantitative assessment, three issues required resolution: the definition of a technical maturity scale, the treatment of ''subjective'' factors which cannot be easily represented in a quantitative format, and the protocol for producing a single technical viability figure-of-merit for each alternative. Alternatives involving the use of foreign facilities were found to be the most technically viable

UV photoreceptors and UV-yellow wing pigments in Heliconius butterflies allow a color signal to serve both mimicry and intraspecific communication.

Science.gov (United States)

Bybee, Seth M; Yuan, Furong; Ramstetter, Monica D; Llorente-Bousquets, Jorge; Reed, Robert D; Osorio, Daniel; Briscoe, Adriana D

2012-01-01

Mimetic wing coloration evolves in butterflies in the context of predator confusion. Unless butterfly eyes have adaptations for discriminating mimetic color variation, mimicry also carries a risk of confusion for the butterflies themselves. Heliconius butterfly eyes, which express recently duplicated ultraviolet (UV) opsins, have such an adaptation. To examine bird and butterfly color vision as sources of selection on butterfly coloration, we studied yellow wing pigmentation in the tribe Heliconiini. We confirmed, using reflectance and mass spectrometry, that only Heliconius use 3-hydroxy-DL-kynurenine (3-OHK), which looks yellow to humans but reflects both UV- and long-wavelength light, whereas butterflies in related genera have chemically unknown yellow pigments mostly lacking UV reflectance. Modeling of these color signals reveals that the two UV photoreceptors of Heliconius are better suited to separating 3-OHK from non-3-OHK spectra compared with the photoreceptors of related genera or birds. The co-occurrence of potentially enhanced UV vision and a UV-reflecting yellow wing pigment could allow unpalatable Heliconius private intraspecific communication in the presence of mimics. Our results are the best available evidence for the correlated evolution of a color signal and color vision. They also suggest that predator visual systems are error prone in the context of mimicry. © 2011 by The University of Chicago.

A comparison of assays measuring the viability of Legionella ...

Science.gov (United States)

Background: The relatively high prevalence of Legionella pneumophila in premise plumbing systems has been widely reported. Published reports indicate Legionella has a comparatively high resistance to chlorine and moreover has the ability to grow in phagocytic amoeba which could provide additional protection in chlorinated drinking water distribution systems. Copper-Silver (Cu-Ag) ionization treatment systems are commercially available for use in large building water systems to help control the risks from Legionella bacteria. The objectives of this study were to develop and optimize Legionella viability assays and use them to investigate the viability of Legionella bacteria after exposure to water treated with coppper and silver ions. Methods: Log phase L. pneumophila cells were used in all experiments and were generated by incubation at 35C for 48 hours in buffered yeast extract broth. Viability assays used included plating on buffered charcoal yeast extract agar to determine the number of culturable cells and treating cells with propidium monoazide (PMA) or ethidium monoazide (EMA) followed by quantitative PCR targeting mip gene of L. pneumophila. The qPCR viability assays were optimized using L. pneumophila inactivated by heat treatment at 65C for 60 min. The effectiveness of Cu-Ag ionization treatment was studied by inoculating L. pneumonia at 105 CFU/mL in water collected directly from a building water system that employed this technology and incubat

Effect of salt hyperosmotic stress on yeast cell viability

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Logothetis Stelios

2007-01-01

Full Text Available During fermentation for ethanol production, yeasts are subjected to different kinds of physico-chemical stresses such as: initially high sugar concentration and low temperature; and later, increased ethanol concentrations. Such conditions trigger a series of biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding osmostress, many studies have been focused on transcriptional activation and gene expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present work was to further our understanding of wine yeast performance during fermentations under osmotic stress conditions. Specifically, the research work focused on the evaluation of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13, particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress conditions energized specific genes to enable yeast cells to survive under stressful conditions. Experiments were designed by pretreating cells with different sodium chloride concentrations (NaCl: 4%, 6% and 10% w/v growing in defined media containing D-glucose and evaluating the impact of this on yeast growth and viability. Subsequent fermentation cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v using salt-adapted cells as inocula. We present evidence that osmostress induced by mild salt pre-treatments resulted in beneficial influences on both cell viability and fermentation performance of an industrial wine yeast strain.

Good genes and sexual selection in dung beetles (Onthophagus taurus: genetic variance in egg-to-adult and adult viability.

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Francisco Garcia-Gonzalez

2011-01-01

Full Text Available Whether species exhibit significant heritable variation in fitness is central for sexual selection. According to good genes models there must be genetic variation in males leading to variation in offspring fitness if females are to obtain genetic benefits from exercising mate preferences, or by mating multiply. However, sexual selection based on genetic benefits is controversial, and there is limited unambiguous support for the notion that choosy or polyandrous females can increase the chances of producing offspring with high viability. Here we examine the levels of additive genetic variance in two fitness components in the dung beetle Onthophagus taurus. We found significant sire effects on egg-to-adult viability and on son, but not daughter, survival to sexual maturity, as well as moderate coefficients of additive variance in these traits. Moreover, we do not find evidence for sexual antagonism influencing genetic variation for fitness. Our results are consistent with good genes sexual selection, and suggest that both pre- and postcopulatory mate choice, and male competition could provide indirect benefits to females.

Viability of infrared FEL facilities

International Nuclear Information System (INIS)

Schwettman, H.A.

2004-01-01

Infrared FELs have broken important ground in optical science in the past decade. The rapid development of optical parametric amplifiers and oscillators, and THz sources, however, has changed the competitive landscape and compelled FEL facilities to identify and exploit their unique advantages. The viability of infrared FEL facilities depends on targeting unique world-class science and providing adequate experimental beam time at competitive costs

Heterozygous effects of irradiated chromosomes on viability in Drosophila melanogaster

International Nuclear Information System (INIS)

Simmons, M.J.

1976-01-01

Two large experiments were conducted in order to evaluate the heterozygous effects of irradiated chromosomes on viability. Mutations were accumulated on several hundred second chromosomes by delivering doses of 2,500R over either two or four generations for total x-ray exposures of 5,000R or 10,000R. Chromosomes treated with 5,000R were screened for lethals after the first treatment, and surviving nonlethals were used to generate families of fully treated chromosomes. The members of these families shared the effects of the first irradiation, but differed with respect to those of the second. The chromosomes treated with 10,000R were not grouped into families since mutations were accumulated independently on each chromosome in that experiment. Heterozygous effects on viability of the irradiated chromosomes were tested in both isogenic (homozygous) and nonisogenic (heterozygous) genetic backgrounds. In conjunction with these tests, homozygous viabilities were determined by the marked-inversion technique. This permitted a separation of the irradiated chromosomes into those which were drastic when made homozygous and those which were not. The results indicate that drastic chromosomes have deleterious effects in heterozygous condition, since viability was reduced by 2 to 4 percent in tests performed with the 10,000R chromosomes, and by 1 percent in those involving the 5,000R material. Within a series of tests, the effects were more pronounced when the genetic background was homozygous. These results suggest that the mutants induced by high doses of x-rays are principally drastic ones which show deleterious effects on viability in heterozygous condition

A Comparison of Real-Time and Endpoint Cell Viability Assays for Improved Synthetic Lethal Drug Validation.

Science.gov (United States)

Single, Andrew; Beetham, Henry; Telford, Bryony J; Guilford, Parry; Chen, Augustine

2015-12-01

Cell viability assays fulfill a central role in drug discovery studies. It is therefore important to understand the advantages and disadvantages of the wide variety of available assay methodologies. In this study, we compared the performance of three endpoint assays (resazurin reduction, CellTiter-Glo, and nuclei enumeration) and two real-time systems (IncuCyte and xCELLigence). Of the endpoint approaches, both the resazurin reduction and CellTiter-Glo assays showed higher cell viabilities when compared directly to stained nuclei counts. The IncuCyte and xCELLigence real-time systems were comparable, and both were particularly effective at tracking the effects of drug treatment on cell proliferation at sub-confluent growth. However, the real-time systems failed to evaluate contrasting cell densities between drug-treated and control-treated cells at full growth confluency. Here, we showed that using real-time systems in combination with endpoint assays alleviates the disadvantages posed by each approach alone, providing a more effective means to evaluate drug toxicity in monolayer cell cultures. Such approaches were shown to be effective in elucidating the toxicity of synthetic lethal drugs in an isogenic pair of MCF10A breast cell lines. © 2015 Society for Laboratory Automation and Screening.

Cationic niosomes an effective gene carrier composed of novel spermine-derivative cationic lipids: effect of central core structures.

Science.gov (United States)

Opanasopit, Praneet; Leksantikul, Lalita; Niyomtham, Nattisa; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Yingyongnarongkul, Boon-Ek

2017-05-01

Cationic niosomes formulated from Span 20, cholesterol (Chol) and novel spermine-based cationic lipids of multiple central core structures (di(oxyethyl)amino, di(oxyethyl)amino carboxy, 3-amino-1,2-dioxypropyl and 2-amino-1,3-dioxypropyl) were successfully prepared for improving transfection efficiency in vitro. The niosomes composed of spermine cationic lipid with central core structure of di(oxyethyl)amino revealed the highest gene transfection efficiency. To investigate the factors affecting gene transfection and cell viability including differences in the central core structures of cationic lipids, the composition of vesicles, molar ratio of cationic lipids in formulations and the weight ratio of niosomes to DNA. Cationic niosomes composed of nonionic surfactants (Span20), cholesterol and spermine-based cationic lipids of multiple central core structures were formulated. Gene transfection and cell viability were evaluated on a human cervical carcinoma cell line (HeLa cells) using pDNA encoding green fluorescent protein (pEGFP-C2). The morphology, size and charge were also characterized. High transfection efficiency was obtained from cationic niosomes composed of Span20:Chol:cationic lipid at the molar ratio of 2.5:2.5:0.5 mM. Cationic lipids with di(oxyethyl)amino as a central core structure exhibited highest transfection efficiency. In addition, there was also no serum effect on transfection efficiency. These novel cationic niosomes may constitute a good alternative carrier for gene transfection.

Human amniotic fluid promotes retinal pigmented epithelial cells' trans-differentiation into rod photoreceptors and retinal ganglion cells.

Science.gov (United States)

Ghaderi, Shima; Soheili, Zahra-Soheila; Ahmadieh, Hamid; Davari, Maliheh; Jahromi, Fatemeh Sanie; Samie, Shahram; Rezaie-Kanavi, Mozhgan; Pakravesh, Jalil; Deezagi, Abdolkhalegh

2011-09-01

To evaluate the effect of human amniotic fluid (HAF) on retinal pigmented epithelial cells growth and trans-differentiation into retinal neurons, retinal pigmented epithelium (RPE) cells were isolated from neonatal human cadaver eye globes and cultured in Dulbecco's modified Eagle's medium-F12 supplemented with 10% fetal bovine serum (FBS). Confluent monolayer cultures were trypsinized and passaged using FBS-containing or HAF-containing media. Amniotic fluid samples were received from pregnant women in the first trimester of gestation. Cell proliferation and death enzyme-linked immunosorbent assays were performed to assess the effect of HAF on RPE cell growth. Trans-differentiation into rod photoreceptors and retinal ganglion cells was also studied using immunocytochemistry and real-time polymerase chain reaction techniques. Primary cultures of RPE cells were successfully established under FBS-containing or HAF-containing media leading to rapid cell growth and proliferation. When RPE cells were moved to in vitro culture system, they began to lose their differentiation markers such as pigmentation and RPE65 marker and trans-differentiated neural-like cells followed by spheroid colonies pertaining to stem/progenitor cells were morphologically detected. Immunocytochemistry (ICC) analysis of HAF-treated cultures showed a considerable expression of Rhodopsin gene (30% Rhodopsin-positive cells) indicating trans-differentiation of RPE cells to rod photoreceptors. Real-time polymerase chain reaction revealed an HAF-dose-dependant expression of Thy-1 gene (RGC marker) and significant promoting effect of HAF on RGCs generation. The data presented here suggest that HAF possesses invaluable stimulatory effect on RPE cells growth and trans-differentiation into retinal neurons. It can be regarded as a newly introduced enriched supplement in serum-free kinds of media used in neuro-retinal regeneration studies.

Photoreceptor change and visual outcome after idiopathic epiretinal membrane removal with or without additional internal limiting membrane peeling.

Science.gov (United States)

Ahn, Seong Joon; Ahn, Jeeyun; Woo, Se Joon; Park, Kyu Hyung

2014-01-01

To compare the postoperative photoreceptor status and visual outcome after epiretinal membrane removal with or without additional internal limiting membrane (ILM) peeling. Medical records of 40 eyes from 37 patients undergoing epiretinal membrane removal with residual ILM peeling (additional ILM peeling group) and 69 eyes from 65 patients undergoing epiretinal membrane removal without additional ILM peeling (no additional peeling group) were reviewed. The length of defects in cone outer segment tips, inner segment/outer segment junction, and external limiting membrane line were measured using spectral domain optical coherence tomography images of the fovea before and at 1, 3, 6, and 12 months after the surgery. Cone outer segment tips and inner segment/outer segment junction line defects were most severe at postoperative 1 month and gradually restored at 12 months postoperatively. The cone outer segment tips line defect in the additional ILM peeling group was significantly greater than that in the no additional peeling group at postoperative 1 month (P = 0.006), and best-corrected visual acuity was significantly worse in the former group at the same month (P = 0.001). There was no significant difference in the defect size and best-corrected visual acuity at subsequent visits and recurrence rates between the two groups. Patients who received epiretinal membrane surgery without additional ILM peeling showed better visual and anatomical outcome than those with additional ILM peeling at postoperative 1 month. However, surgical outcomes were comparable between the two groups, thereafter. In terms of visual outcome and photoreceptor integrity, additional ILM peeling may not be an essential procedure.

Detection of viability by percent thallium uptake with conventional thallium scintigraphy

International Nuclear Information System (INIS)

Imai, Kamon; Araki, Yasushi; Horiuchi, Kou-ichi; Yumikura, Sei; Saito, Satoshi; Ozawa, Yukio; Kan-matsuse, Katsuo; Hagiwara, Kazuo.

1994-01-01

Thallium myocardial scintigraphy (TMS) is used for diagnosis of viability in infarcted myocardium before coronary revascularization. Underestimation of viability by TMS has been reported by many investigators. To evaluate viability precisely, thallium re-injection method or 24 hour delayed imaging is performed. However, these techniques are not convenient and are difficult to perform in clinical practice. Percent T1-uptake method was developed for predicting myocardial viability. To evaluate usefulness of this method, TMS was performed before and after PTCA in 23 patients with myocardial infarction. Left ventricle was divided into 3 layers, then each layer was divided into 4 segments (12 segments in total). Forth three segments showed recovery of perfusion on TMS after PTCA. Viability in infarcted myocardium is predicted by 1) redistribution (RD), 2) %T1-uptake≥45% on the image immediately after exercise (TE), and 3) %T1-uptake≥45% on delayed image (TD). Sensitivity was RD: 60%, TE: 90% and TD: 95% (p<0.001 vs. RD). Specificity was RD: 74%, TE: 68%, and TD: 60% (NS). Predictive accuracy (PA) was RD: 69%, TE: 77%, TD: 73% (NS). Compared with RD, %T1-uptake, either TE or TD, increased sensitivity with slightly improved PA, but decreased specificity slightly. Therefore %T1-uptake would be a sensitive and useful predictor to find patients who are most likely to benefit from re-vascularization. (author)

Predicting climate change extirpation risk for central and southern Appalachian forest tree species

Science.gov (United States)

Kevin M. Potter; William W. Hargrove; Frank H. Koch

2010-01-01

Climate change will likely pose a severe threat to the viability of certain forest tree species, which will be forced either to adapt to new conditions or to shift to more favorable environments if they are to survive. Several forest tree species of the central and southern Appalachians may be at particular risk, since they occur in limited high-elevation ranges and/or...

Present trends in the detection of myocardial viability using nuclear cardiology tests

International Nuclear Information System (INIS)

Peix Gonzalez, Amalia; Garcia Barreto, David

1999-01-01

The myocardial viability diagnosis is important for those who will undergo myocardial revascularization whether by surgery or coronary angioplasty. Our purpose is to present some of the present trends in the detection of myocardial viability using nuclear cardiology tests. Emphasis is made on the estimation of radiopharmaceutical uptake and the use of vasodilators in perfusion scintigraphy mainly with technetium-labeled compounds. Also, the current possibilities for a myocardial metabolism study using single-photon emission-computed tomography as well as some clinical implications of myocardial viability are set forth

Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish

DEFF Research Database (Denmark)

Garm, Anders Lydik; Mori, S.

2009-01-01

Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each with a s......Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...... when stimulated and provokes a strong increase in the pacemaker frequency upon light-off. The upper lens eye, the pit eyes and the rhopalial neuropil all have close to the opposite effect. When these responses are compared with all-eye stimulations it is seen that some advanced integration must take...

High-resolution crystal structures of the photoreceptor glyceraldehyde 3-phosphate dehydrogenase (GAPDH) with three and four-bound NAD molecules

Science.gov (United States)

Baker, Bo Y; Shi, Wuxian; Wang, Benlian; Palczewski, Krzysztof

2014-01-01

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the oxidative phosphorylation of d-glyceraldehyde 3-phosphate (G3P) into 1,3-diphosphoglycerate (BGP) in the presence of the NAD cofactor. GAPDH is an important drug target because of its central role in glycolysis, and nonglycolytic processes such as nuclear RNA transport, DNA replication/repair, membrane fusion and cellular apoptosis. Recent studies found that GAPDH participates in the development of diabetic retinopathy and its progression after the cessation of hyperglycemia. Here, we report two structures for native bovine photoreceptor GAPDH as a homotetramer with differing occupancy by NAD, bGAPDH(NAD)4, and bGAPDH(NAD)3. The bGAPDH(NAD)4 was solved at 1.52 Å, the highest resolution for GAPDH. Structural comparison of the bGAPDH(NAD)4 and bGAPDH(NAD)3 models revealed novel details of conformational changes induced by cofactor binding, including a loop region (residues 54–56). Structure analysis of bGAPDH confirmed the importance of Phe34 in NAD binding, and demonstrated that Phe34 was stabilized in the presence of NAD but displayed greater mobility in its absence. The oxidative state of the active site Cys149 residue is regulated by NAD binding, because this residue was found oxidized in the absence of dinucleotide. The distance between Cys149 and His176 decreased upon NAD binding and Cys149 remained in a reduced state when NAD was bound. These findings provide an important structural step for understanding the mechanism of GAPDH activity in vision and its pathological role in retinopathies. PMID:25176140

How can EPR spectroscopy help to unravel molecular mechanisms of flavin-dependent photoreceptors?

Directory of Open Access Journals (Sweden)

Daniel eNohr

2015-09-01

Full Text Available Electron paramagnetic resonance (EPR spectroscopy is a well-established spectroscopic method for the examination of paramagnetic molecules. Proteins can contain paramagnetic moieties in form of stable cofactors, transiently formed intermediates, or spin labels artificially introduced to cysteine sites. The focus of this review is to evaluate potential scopes of application of EPR to the emerging field of optogenetics. The main objective for EPR spectroscopy in this context is to unravel the complex mechanisms of light-active proteins, from their primary photoreaction to downstream signal transduction. An overview of recent results from the family of flavin-containing, blue-light dependent photoreceptors is given. In detail, mechanistic similarities and differences are condensed from the three classes of flavoproteins, the cryptochromes, LOV (Light-oxygen-voltage, and BLUF (blue-light using FAD domains. Additionally, a concept that includes spin-labeled proteins and examination using modern pulsed EPR is introduced, which allows for a precise mapping of light-induced conformational changes.

How can EPR spectroscopy help to unravel molecular mechanisms of flavin-dependent photoreceptors?

Science.gov (United States)

Nohr, Daniel; Rodriguez, Ryan; Weber, Stefan; Schleicher, Erik

2015-01-01

Electron paramagnetic resonance (EPR) spectroscopy is a well-established spectroscopic method for the examination of paramagnetic molecules. Proteins can contain paramagnetic moieties in form of stable cofactors, transiently formed intermediates, or spin labels artificially introduced to cysteine sites. The focus of this review is to evaluate potential scopes of application of EPR to the emerging field of optogenetics. The main objective for EPR spectroscopy in this context is to unravel the complex mechanisms of light-active proteins, from their primary photoreaction to downstream signal transduction. An overview of recent results from the family of flavin-containing, blue-light dependent photoreceptors is given. In detail, mechanistic similarities and differences are condensed from the three classes of flavoproteins, the cryptochromes, LOV (Light-oxygen-voltage), and BLUF (blue-light using FAD) domains. Additionally, a concept that includes spin-labeled proteins and examination using modern pulsed EPR is introduced, which allows for a precise mapping of light-induced conformational changes.

Sustainable model for financial viability of decentralized biomass gasifier based power projects

NARCIS (Netherlands)

Palit, D.; Malhotra, R.; Kumar, Atul

2011-01-01

This paper made a modest attempt for designing a sustainable model for financial viability of biomass gasifier power projects for enhancing electricity access in India and other developing countries. For long term sustainability of distributed generation projects in remote rural areas, viability

Effect of storage temperature on Streptococcus mutans viability

Directory of Open Access Journals (Sweden)

Ana Lídia Soares COTA

2018-04-01

Full Text Available Abstract Introduction Proper storage conditions and maintenance of viable biological material plays an important role in microbiological research, allowing for the opportunity to conduct future studies. Objective To evaluate the viability of Streptococcus mutans strains that were previously grown and stored under different temperatures for approximately eight years. Material and method In this study, we evaluated 393 bacterial isolates that were stored in a freezer at -80°C (G1 and 200 isolates stored in a freezer at -20°C (G2. Aliquots of each sample were plated on blood agar and mitis-salivarius bacitracin sucrose agar-solidified medium. After incubating under microaerophilic conditions in an incubator at 37°C for 72 hours, the presence, morphology and purity of bacterial growth was observed. The data were analyzed by means of descriptive statistics. Result Microbial viability was observed in almost all samples (99.7% in G1, whereas all isolates stored at -20°C were considered inviable. Conclusion The viability of S. mutans is influenced by the storage temperature of the samples, and the strains remain viable when stored under ideal temperature conditions (-80°C, even when stored for a long period of time.

Assessment of myocardial perfusion and metabolism for assessment of myocardial viability

International Nuclear Information System (INIS)

Beller, G.

1996-01-01

Identifying preserved myocardial viability in the presence of severe regional left ventricular dysfunction is becoming increasingly more important for clinical decision-making to better select those patients with coronary artery disease who will benefit most from revascularization. 201 Tl remains the most commonly employed radionuclide for detecting both ischemia and viability. A severe persistent defect with 201 Tl uptake compared to peak to improved perfusion and corresponding improved function after revascularisation. Detection of defect reversibility on 201 Tl imaging is enhanced by 'reinjection' of a second 201 Tl dose after acquisition of redistribution images. Initial and 4-hour rest/redistribution imaging has proven most usefull for detection of viability in the resting state in patients with ischemic cardiomyopathy. The greater the extent of preoperative viability, the greater is the improvement in regional and global function after revascularisation. 99 Tc sestamibi has also been demonstrated to be extracted by myocardial cells in proportion to regional blood flow in the presence of viable myocities. Although this agrnt does not redistribute after intravenous injection, its >50% uptake of the tracer implies viablility and predicts improved regional function after revascularisation. Finally positron emission tomography with 18 F fluorodeoxoglucose (FDG) is perhaps the most sensitive noninvasive imaging technique for detection of viability in stunned or hibernating myocardium. A mismatch pattern between regional flow and FDG uptake as approximately an 80-85% positive preicted value for predicting improved function in asynergic myocardial regions after revascualarisation

Non-directional photoreceptors in the pluteus of Strongylocentrotus purpuratus

Directory of Open Access Journals (Sweden)

Alberto Valero-Gracia

2016-11-01

Full Text Available In comparison to complex visual systems, non-directional photoreception – the most primitive form of biological photodetection – has been poorly investigated, although it is essential to many biological processes such as circadian and seasonal rhythms. Here we describe the spatiotemporal expression pattern of the major molecular actors mediating light reception – opsins – localized in the Strongylocentrotus purpuratus larva. In contrast to other zooplanktonic larvae, the echinopluteus lacks photoreceptor cells with observable shading pigments involved in directional visual tasks. Nonetheless, the echinopluteus expresses two distinct classes of opsins: a Go-opsin and a rhabdomeric opsin. The Go-opsin, Sp-opsin3.2, is detectable at early (3 days post fertilization and four armed pluteus stages (4 days post fertilization in two cells that flank the apical organ. To rule out the presence of shading pigments involved in directional photoreception, we used electron microscopy to explore the expression domain of Go-opsin Sp-opsin3.2 positive cells. The rhabdomeric opsin Sp-Opsin4 expression is detectable in clusters of cells located around the primary podia at the five-fold ectoderm pentagonal disc stage (day 18-21 and thereafter, thus indicating that Sp-Opsin4 may not be involved in the photoreception mechanism of the larva, but only of the juvenile. We discuss the putative function of the relevant cells in their neural context, and propose a model for understanding simple photodetection in marine larvae.

Comparison of tissue viability imaging and colorimetry: skin blanching.

Science.gov (United States)

Zhai, Hongbo; Chan, Heidi P; Farahmand, Sara; Nilsson, Gert E; Maibach, Howard I

2009-02-01

Operator-independent assessment of skin blanching is important in the development and evaluation of topically applied steroids. Spectroscopic instruments based on hand-held probes, however, include elements of operator dependence such as difference in applied pressure and probe misalignment, while laser Doppler-based methods are better suited for demonstration of skin vasodilatation than for vasoconstriction. To demonstrate the potential of the emerging technology of Tissue Viability Imaging (TiVi) in the objective and operator-independent assessment of skin blanching. The WheelsBridge TiVi600 Tissue Viability Imager was used for quantification of human skin blanching with the Minolta chromameter CR 200 as an independent colorimeter reference method. Desoximetasone gel 0.05% was applied topically on the volar side of the forearm under occlusion for 6 h in four healthy adults. In a separate study, the induction of blanching in the occlusion phase was mapped using a transparent occlusion cover. The relative uncertainty in the blanching estimate produced by the Tissue Viability Imager was about 5% and similar to that of the chromameter operated by a single user and taking the a(*) parameter as a measure of blanching. Estimation of skin blanching could also be performed in the presence of a transient paradoxical erythema, using the integrated TiVi software. The successive induction of skin blanching during the occlusion phase could readily be mapped by the Tissue Viability Imager. TiVi seems to be suitable for operator-independent and remote mapping of human skin blanching, eliminating the main disadvantages of methods based on hand-held probes.

Micro-calibration of space and motion by photoreceptors synchronized in parallel with cortical oscillations: A unified theory of visual perception.

Science.gov (United States)

Jerath, Ravinder; Cearley, Shannon M; Barnes, Vernon A; Jensen, Mike

2018-01-01

A fundamental function of the visual system is detecting motion, yet visual perception is poorly understood. Current research has determined that the retina and ganglion cells elicit responses for motion detection; however, the underlying mechanism for this is incompletely understood. Previously we proposed that retinogeniculo-cortical oscillations and photoreceptors work in parallel to process vision. Here we propose that motion could also be processed within the retina, and not in the brain as current theory suggests. In this paper, we discuss: 1) internal neural space formation; 2) primary, secondary, and tertiary roles of vision; 3) gamma as the secondary role; and 4) synchronization and coherence. Movement within the external field is instantly detected by primary processing within the space formed by the retina, providing a unified view of the world from an internal point of view. Our new theory begins to answer questions about: 1) perception of space, erect images, and motion, 2) purpose of lateral inhibition, 3) speed of visual perception, and 4) how peripheral color vision occurs without a large population of cones located peripherally in the retina. We explain that strong oscillatory activity influences on brain activity and is necessary for: 1) visual processing, and 2) formation of the internal visuospatial area necessary for visual consciousness, which could allow rods to receive precise visual and visuospatial information, while retinal waves could link the lateral geniculate body with the cortex to form a neural space formed by membrane potential-based oscillations and photoreceptors. We propose that vision is tripartite, with three components that allow a person to make sense of the world, terming them "primary, secondary, and tertiary roles" of vision. Finally, we propose that Gamma waves that are higher in strength and volume allow communication among the retina, thalamus, and various areas of the cortex, and synchronization brings cortical

Flat choroidal melanoma masquerading as central serous chorioretinopathy

Directory of Open Access Journals (Sweden)

Timothy Patrick Higgins

2016-01-01

Full Text Available There are several mimickers of choroidal melanoma. We report a patient with recent family stress who developed blurred vision to 20/50 OD and was found to have unilateral central serous chorioretinopathy and a coincidental choroidal nevus. After 1 year without resolution of the subretinal fluid, the patient was referred for our opinion. On examination, visual acuity was 20/50 in the right eye and 20/20 in the left eye. The left eye was normal. Evaluation of the right eye showed a small, pigmented submacular choroidal lesion measuring 4 mm Χ 3 mm. Ultrasonography documented an isoechoic mass measuring 1.71 mm in thickness. Optical coherence tomography showed subretinal fluid with shaggy photoreceptors and hyper-reflective material within the subretinal fluid, likely indicative of lipofuscin within macrophages. Autofluorescence revealed orange pigment overlying the lesion. These features were strongly suggestive of small choroidal melanoma with five risk factors for tumor growth. Treatment with Iodine-125 plaque brachytherapy was performed on the patient. The readers should keep in mind that choroidal melanoma can manifest as a tiny choroidal mass with related multimodal imaging features of subretinal fluid and orange pigment.

Unravelling the molecular basis for light modulated cellulase gene expression - the role of photoreceptors in Neurospora crassa

Science.gov (United States)

2012-01-01

Background Light represents an important environmental cue, which exerts considerable influence on the metabolism of fungi. Studies with the biotechnological fungal workhorse Trichoderma reesei (Hypocrea jecorina) have revealed an interconnection between transcriptional regulation of cellulolytic enzymes and the light response. Neurospora crassa has been used as a model organism to study light and circadian rhythm biology. We therefore investigated whether light also regulates transcriptional regulation of cellulolytic enzymes in N. crassa. Results We show that the N. crassa photoreceptor genes wc-1, wc-2 and vvd are involved in regulation of cellulase gene expression, indicating that this phenomenon is conserved among filamentous fungi. The negative effect of VVD on production of cellulolytic enzymes is thereby accomplished by its role in photoadaptation and hence its function in White collar complex (WCC) formation. In contrast, the induction of vvd expression by the WCC does not seem to be crucial in this process. Additionally, we found that WC-1 and WC-2 not only act as a complex, but also have individual functions upon growth on cellulose. Conclusions Genome wide transcriptome analysis of photoreceptor mutants and evaluation of results by analysis of mutant strains identified several candidate genes likely to play a role in light modulated cellulase gene expression. Genes with functions in amino acid metabolism, glycogen metabolism, energy supply and protein folding are enriched among genes with decreased expression levels in the wc-1 and wc-2 mutants. The ability to properly respond to amino acid starvation, i. e. up-regulation of the cross pathway control protein cpc-1, was found to be beneficial for cellulase gene expression. Our results further suggest a contribution of oxidative depolymerization of cellulose to plant cell wall degradation in N. crassa. PMID:22462823

Independent signaling by Drosophila insulin receptor for axon guidance and growth.

Science.gov (United States)

Li, Caroline R; Guo, Dongyu; Pick, Leslie

2013-01-01

The Drosophila insulin receptor (DInR) regulates a diverse array of biological processes including growth, axon guidance, and sugar homeostasis. Growth regulation by DInR is mediated by Chico, the Drosophila homolog of vertebrate insulin receptor substrate proteins IRS1-4. In contrast, DInR regulation of photoreceptor axon guidance in the developing visual system is mediated by the SH2-SH3 domain adaptor protein Dreadlocks (Dock). In vitro studies by others identified five NPXY motifs, one in the juxtamembrane region and four in the signaling C-terminal tail (C-tail), important for interaction with Chico. Here we used yeast two-hybrid assays to identify regions in the DInR C-tail that interact with Dock. These Dock binding sites were in separate portions of the C-tail from the previously identified Chico binding sites. To test whether these sites are required for growth or axon guidance in whole animals, a panel of DInR proteins, in which the putative Chico and Dock interaction sites had been mutated individually or in combination, were tested for their ability to rescue viability, growth and axon guidance defects of dinr mutant flies. Sites required for viability were identified. Unexpectedly, mutation of both putative Dock binding sites, either individually or in combination, did not lead to defects in photoreceptor axon guidance. Thus, either sites also required for viability are necessary for DInR function in axon guidance and/or there is redundancy built into the DInR/Dock interaction such that Dock is able to interact with multiple regions of DInR. We also found that simultaneous mutation of all five NPXY motifs implicated in Chico interaction drastically decreased growth in both male and female adult flies. These animals resembled chico mutants, supporting the notion that DInR interacts directly with Chico in vivo to control body size. Mutation of these five NPXY motifs did not affect photoreceptor axon guidance, segregating the roles of DInR in the

Economic Viability of Brewery Spent Grain as a Biofuel

Energy Technology Data Exchange (ETDEWEB)

Morrow, Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-01

This report summarizes an investigation into the technical feasibility and economic viability of use grain wastes from the beer brewing process as fuel to generate the heat needed in subsequent brewing process. The study finds that while use of spent grain as a biofuel is technically feasible, the economics are not attractive. Economic viability is limited by the underuse of capital equipment. The investment in heating equipment requires a higher utilization that the client brewer currently anticipates. It may be possible in the future that changing factors may swing the decision to a more positive one.

Viability Assessment Volume 1

International Nuclear Information System (INIS)

1998-01-01

Since May 1996, under its draft Civilian Radioactive Waste Management Program Plan (DOE 1996), DOE has been carrying out a 5-year program of work to support the decision in 2001 by the Secretary of Energy on whether or not to recommend the site to the President. Part of this program was to address major unresolved technical issues and to complete an assessment of the viability of the Yucca Mountain site by 1998. Affirming the DOE plans, Congress directed DOE in the 1997 Energy and Water Development Appropriations Act to provide a viability assessment of the Yucca Mountain site to Congress and the President. This Viability Assessment (VA) document is the DOE report to Congress and the President. They are expected to use the VA to make an informed decision about program direction and funding. Drawing on 15 years of scientific investigation and design work at Yucca Mountain, the VA summarizes a large technical basis of field investigations, laboratory tests, models, analyses, and engineering, described in cited references. The VA identifies the major uncertainties relevant to the technical defensibility of DOE analyses and designs, the DOE approach to managing these uncertainties, and the status of work toward the site recommendation and LA. The VA also identifies DOE plans for the remaining work, and the estimated costs of completing an LA and constructing and operating a repository. The attention to uncertainties is important because DOE must evaluate how the repository will perform during the next 10,000 years or longer. Uncertainties exist because of variability in the natural (geologic and hydrologic) systems at Yucca Mountain and because of imperfect scientific understanding of the natural processes that might affect the repository system. This is Volume 1 and it covers, Introduction and Site Characteristics, includes a high-level summary of the results of the VA and some additional background information. (The overview is bound separately.) Section 1 of Volume

Influence of harvesting and processing methods on organic viability of soybean seed

Directory of Open Access Journals (Sweden)

Đukanović Lana

2000-01-01

Full Text Available Organic viability of soybean seed for three soybean varieties - elite (Bosa, ZPS 015 and Nena depending on methods of manipulation with seeds during harvesting and processing phase were determined in this paper. Trial was conducted in Zemun Polje during 1999; manual and mechanized harvesting or processing methods were applied. Seed germination was tested using ISTA methods (Standard method and Cold test. Following parameters were evaluated: germination viability, germination, rate-speed of emergence, length of hypocotile and main root Rate-speed of emergence was based on number of emerged plants per day. Length of hypocotile or root and percent of germination determined vigour index. Based on obtained results it maybe concluded that methods of seed manipulation during harvesting or processing phase were influenced on soybean seed quality parameters evaluated. Ways of seed manipulation - methods evaluated were influenced organic viability of soybean seed by decreasing germination viability, total germination and length of main root.

BMI1 loss delays photoreceptor degeneration in Rd1 mice. Bmi1 loss and neuroprotection in Rd1 mice.

Science.gov (United States)

Zencak, Dusan; Crippa, Sylvain V; Tekaya, Meriem; Tanger, Ellen; Schorderet, Daniel E; Munier, Francis L; van Lohuizen, Maarten; Arsenijevic, Yvan

2006-01-01

Retinitis pigmentosa (RP) is a heterogeneous group of genetic disorders leading to blindness, which remain untreatable at present. Rd1 mice represent a recognized model of RP, and so far only GDNF treatment provided a slight delay in the retinal degeneration in these mice. Bmi1, a transcriptional repressor, has recently been shown to be essential for neural stem cell (NSC) renewal in the brain, with an increased appearance of glial cells in vivo in Bmi1 knockout (Bmi1-/-) mice. One of the roles of glial cells is to sustain neuronal function and survival. In the view of a role of the retinal Miller glia as a source of neural protection in the retina, the increased astrocytic population in the Bmi1-/- brain led us to investigate the effect of Bmi1 loss in Rd1 mice. We observed an increase of Müller glial cells in Rd1-Bmi1-/- retinas compared to Rd1. Moreover, Rd1-Bmi1-/- mice showed 7-8 rows of photoreceptors at 30 days of age (P30), while in Rd1 littermates there was a complete disruption of the outer nuclear layer (ONL). Preliminary ERG results showed a responsiveness of Rd1-Bmi1-/- mice in scotopic vision at P35. In conclusion, Bmi1 loss prevented, or rescued, photoreceptors from degeneration to an unanticipated extent in Rd1 mice. In this chapter, we will first provide a brief review of our work on the cortical NSCs and introduce the Bmi1 oncogene, thus offering a rational to our observations on the retina.

Variation in rhodopsin kinase expression alters the dim flash response shut off and the light adaptation in rod photoreceptors.

Science.gov (United States)

Sakurai, Keisuke; Young, Joyce E; Kefalov, Vladimir J; Khani, Shahrokh C

2011-08-29

Rod photoreceptors are exquisitely sensitive light detectors that function in dim light. The timely inactivation of their light responses is critical for the ability of rods to reliably detect and count photons. A key step in the inactivation of the rod transduction is the phosphorylation of the rod visual pigment, rhodopsin, catalyzed by G-protein-dependent receptor kinase 1 (GRK1). Absence of GRK1 greatly prolongs the photoreceptors' light response and enhances their susceptibility to degeneration. This study examined the light responses from mouse rods expressing various levels of GRK1 to evaluate how their function is modulated by rhodopsin inactivation. Transretinal and single-cell rod electrophysiological recordings were obtained from several strains of mice expressing GRK1 at 0.3- to 3-fold the wild-type levels. The effect of GRK1 expression level on the function of mouse rods was examined in darkness and during background adaptation. Altering the expression of GRK1 from 0.3- to 3-fold that in wild-type rods had little effect on the single photon response amplitude. Notably, increasing the expression level of GRK1 accelerated the dim flash response shut off but had no effect on the saturated response shut off. Additionally, GRK1 excess abolished the acceleration of saturated responses shut off during light adaptation. These results demonstrate that rhodopsin inactivation can modulate the kinetics of recovery from dim light stimulation. More importantly, the ratio of rhodopsin kinase to its modulator recoverin appears critical for the proper adaptation of rods and the acceleration of their response shut off in background light.

Nuclear Power Options Viability Study. Volume 4. Bibliography

Energy Technology Data Exchange (ETDEWEB)

Trauger, D B; White, J D; Sims, J W [eds.

1986-09-01

Documents in the Nuclear Power Options Viability Study (NPOVS) bibliography are classified under one of four headings or categories as follows: nuclear options; light water reactors; liquid metal reactors; and high temperature reactors. The collection and selection of these documents, beginning early in 1984 and continuing through March of 1986, was carried out in support of the study's objective: to explore the viabilities of several nuclear electric power generation options for commercial deployment in the United States between 2000 and 2010. There are approximately 550 articles, papers, reports, and books in the bibliography that have been selected from some 2000 surveyed. The citations have been made computer accessible to facilitate rapid on-line retrieval by keyword, author, corporate author, title, journal name, or document number.

Nuclear Power Options Viability Study. Volume 4. Bibliography

International Nuclear Information System (INIS)

Trauger, D.B.; White, J.D.; Sims, J.W.

1986-09-01

Documents in the Nuclear Power Options Viability Study (NPOVS) bibliography are classified under one of four headings or categories as follows: nuclear options; light water reactors; liquid metal reactors; and high temperature reactors. The collection and selection of these documents, beginning early in 1984 and continuing through March of 1986, was carried out in support of the study's objective: to explore the viabilities of several nuclear electric power generation options for commercial deployment in the United States between 2000 and 2010. There are approximately 550 articles, papers, reports, and books in the bibliography that have been selected from some 2000 surveyed. The citations have been made computer accessible to facilitate rapid on-line retrieval by keyword, author, corporate author, title, journal name, or document number

Inverted nuclear architecture and its development during differentiation of mouse rod photoreceptor cells: a new model to study nuclear architecture.

Science.gov (United States)

Solovei, I; Joffe, B

2010-09-01

Interphase nuclei have a conserved architecture: heterochromatin occupies the nuclear periphery, whereas euchromatin resides in the nuclear interior. It has recently been found that rod photoreceptor cells of nocturnal mammals have an inverted architecture, which transforms these nuclei in microlenses and supposedly facilitates a reduction in photon loss in the retina. This unique deviation from the nearly universal pattern throws a new light on the nuclear organization. In the article we discuss the implications of the studies of the inverted nuclei for understanding the role of the spatial organization of the nucleus in nuclear functions.

Radiopeptide internalisation and externalisation assays: Cell viability and radioligand integrity

International Nuclear Information System (INIS)

Raza Naqvi, Syed Ali; Sosabowski, Jane K.; Ahamad Nagra, Saeed; Ishfaq, Malik M.; Mather, Stephen J.; Matzow, Torkjel

2011-01-01

Various aspects of radiopeptide receptor-mediated cell internalisation and externalisation assays were assessed, including the integrity of externalised peptides and the effect of varying the pH and incubation time of the acid wash step (to remove surface receptor-bound ligand) on efficacy and cell viability. The observed intact proportion of externalised peptide was 5-10%, and acid wash buffers with pH 2.8 or below were found to be detrimental to cell viability and integrity, particularly following prolonged incubation times.

Is cell viability always directly related to corrosion resistance of stainless steels?

International Nuclear Information System (INIS)

Salahinejad, E.; Ghaffari, M.; Vashaee, D.; Tayebi, L.

2016-01-01

It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

Is cell viability always directly related to corrosion resistance of stainless steels?

Energy Technology Data Exchange (ETDEWEB)

Salahinejad, E., E-mail: salahinejad@kntu.ac.ir [Faculty of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Bruker AXS Inc., 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Vashaee, D. [Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Tayebi, L. [Department of Developmental Sciences, Marquette University School of Dentistry, Milwaukee, WI 53201 (United States); Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom)

2016-05-01

It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

Normative data of outer photoreceptor layer thickness obtained by software image enhancing based on Stratus optical coherence tomography images

DEFF Research Database (Denmark)

Christensen, U.C.; Krøyer, K.; Thomadsen, Jakob

2008-01-01

backscattered light within the outer nuclear layer (ONL) in the fovea was registered and compared with backscattered light within the ONL in the peripheral part of the macula (I-ratio-ONL). Results: The mean RPE-OScomplex thickness in the foveal centre was 77.2 mu m (SD = 3.95). The RPE-OScomplex thickness...... in the superior macula 0.5-3 mm of the centre was significantly increased as compared with the corresponding inferior retina. In healthy subjects, the I-ratio-ONL was 1.06. Conclusions: Contrast-enhanced OCT images enable quantification of outer photoreceptor layer thickness, and normative values may help...

Impact of age and diagnosis on viability during centrifugation and cryopreservation of peripheral blood stem cell products.

Science.gov (United States)

Civriz Bozdag, S; Bay, M; Ayyıldız, E; Topcuoglu, P; Ilhan, O

2012-08-01

The viability of the hematopoietic stem cells infused to the patient is important for transplant outcome. We evaluated 31 peripheral blood stem cell product collected from 15 patients. We aimed to check the viabilities of the cells from patients with different age and diagnosis, in different stages of the cryopreservation procedure. We showed a markedly decreased viability rate after centrifugation and addition of DMSO. Percentages of viabilities were similar between young and old patients in each step. Type of hematological malignancy did not make a significant influence on the viability. High speed centrifugation has a negative impact on the viability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects induced on the transverse-spatial-impulse response of an inhomogeneous photoreceptor with a nonsymmetric refractive index profile and arbitrarily located origin

Energy Technology Data Exchange (ETDEWEB)

Calvo, M.L.; Mondal, P.K.

1987-03-01

In a few earlier communications, spatial-transverse-impulse response (STIR) associated with the initial field transversely distributed across the entrance pupil of an inhomogeneous optical wave guide (photoreceptor) has been investigated. In the present work, effects of indetermination in the location of the origin on an arbitrarily defined refractive index profile, representing the degree of inhomogeneity at the aperture pupil of a single receptor, have been studied. Some consequences related to a few possible technical applications have been discussed.

Linking population viability, habitat suitability, and landscape simulation models for conservation planning

Science.gov (United States)

Michael A. Larson; Frank R., III Thompson; Joshua J. Millspaugh; William D. Dijak; Stephen R. Shifley

2004-01-01

Methods for habitat modeling based on landscape simulations and population viability modeling based on habitat quality are well developed, but no published study of which we are aware has effectively joined them in a single, comprehensive analysis. We demonstrate the application of a population viability model for ovenbirds (Seiurus aurocapillus)...

[Selective retina therapy in central serous chorioretinopathy with detachment of the pigmentary epithelium].

Science.gov (United States)

Klatt, C; Elsner, H; Pörksen, E; Brinkmann, R; Bunse, A; Birngruber, R; Roider, J

2006-10-01

Selective Retina Therapy (SRT) is a new and innovative laser treatment modality that selectively treats the retinal pigmentary epithelium while sparing the photoreceptors. This therapeutic concept appears to be particularly suitable for treating patients with acute or chronic central serous chorioretinopathy (CSC). We present preliminary results obtained in five patients who had CSC associated with pigmentary epithelium detachment (PED) and serous subretinal fluid (SRF) and who were treated with SRT. This case series was made up of five male patients (mean age 47 years) with chronic CSC and SRF resulting from PED. Examinations performed before and at 1 month and 3 months after the treatment were: BCVA, FLA, OCT (Zeiss OCT III). For SRT, confluent treatment of the PED (area of leakage) was carried out using a pulsed frequency-doubled, Q-switched Nd-YLF prototype laser (lambda=527 nm, t= 1.7 s, 100 Hz, energy = 150-250 J). Best corrected visual acuity at baseline was 0.53, while after 4 weeks it was 0.56 and after 12 weeks, 0.5. At baseline leakage was seen at the PED on fluorescein angiography in all patients. After 4 weeks leakage activity was no longer noted on angiography in 4 of 5 patients. OCT at baseline showed SRF at the edge of the PED in all patients, but in 4 of the 5 patients this was no longer detectable after 4 weeks. SRT is a safe and effective treatment for patients with CSC in which PED has caused SRF. Not a single case of rip syndrome was observed in this study, even though the PED was treated confluently. Since SRT spares the photoreceptors it is particularly suitable for the treatment of CSC, especially when the origin of leakage is located close to the fovea. The results indicate that SRT leads to reconstruction of the outer blood-retina barrier.

LIVE/DEAD YEAST VIABILITY STAINING AS A TOOL FOR IMPROVING ARTISANAL PILSNER BEER PRODUCTION

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Benedetta Bottari

2014-10-01

Full Text Available The production of an artisanal beer, made by brewers using traditional practices on a small scale, is founded on the empirical adjustment of parameters, including yeasts handling and serial repitching. The aim of this study was to monitor yeast viability during different stages of artisanal beer productions through the Live/Dead Yeast viability staining and to correlate it with fermentation dynamics in order to increase process standardization and to maintain the quality of final products. Yeast viability and fermentation activities were evaluated during seven fermentation cycles of an artisanal pilsner beer. Yeast inoculated with higher viability performed generally better in fermentation, resulting in faster sugar consumption, faster ethanol production and stability. Handling yeast and serial repitching based on Live/Dead viability measurements, could be the key way to ensure reliable manufacture of high quality beer and to improve process standardization particularly for microbreweries, where variability of production can be a challenging point.

Drying process strongly affects probiotics viability and functionalities.

Science.gov (United States)

Iaconelli, Cyril; Lemetais, Guillaume; Kechaou, Noura; Chain, Florian; Bermúdez-Humarán, Luis G; Langella, Philippe; Gervais, Patrick; Beney, Laurent

2015-11-20

Probiotic formulations are widely used and are proposed to have a variety of beneficial effects, depending on the probiotic strains present in the product. The impact of drying processes on the viability of probiotics is well documented. However, the impact of these processes on probiotics functionality remains unclear. In this work, we investigated variations in seven different bacterial markers after various desiccation processes. Markers were composed of four different viability evaluation (combining two growth abilities and two cytometric measurements) and in three in vitro functionalities: stimulation of IL-10 and IL-12 production by PBMCs (immunomodulation) and bacterial adhesion to hexadecane. We measured the impact of three drying processes (air-drying, freeze-drying and spray-drying), without the use of protective agents, on three types of probiotic bacteria: Bifidobacterium bifidum, Lactobacillus plantarum and Lactobacillus zeae. Our results show that the bacteria respond differently to the three different drying processes, in terms of viability and functionality. Drying methods produce important variations in bacterial immunomodulation and hydrophobicity, which are correlated. We also show that adherence can be stimulated (air-drying) or inhibited (spray-drying) by drying processes. Results of a multivariate analysis show no direct correlation between bacterial survival and functionality, but do show a correlation between probiotic responses to desiccation-rewetting and the process used to dry the bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

Morpho-anatomy, imbibition, viability and germination of the seed of Anadenanthera colubrina var. cebil (Fabaceae).

Science.gov (United States)

Varela, Rodolfo Omar; Albornoz, Patricia Liliana

2013-09-01

Seed biology is a relevant aspect of tropical forests because it is central to the understanding of processes of plant establishment, succession and natural regeneration. Anadenanthera colubrina var. cebil is a timber tree from South America that produces large seeds with thin weak teguments, which is uncommon among legumes. This study describes the morphology and anatomy of the seed coat, the viability, imbibition, and germination in this species. Seeds used during the essays came from 10 trees that grow naturally in Horco Molle, province of Tucumán, Argentina. Seed morphology was described from a sample of 20 units. The seed coat surface was examined with a scanning electron microscope. Transverse sections of hydrated and non-hydrated seeds were employed to describe the histological structure of the seed coat. Hydration, viability and germination experiments were performed under laboratory controlled conditions; and the experimental design consisted of 10 replicas of 10 seeds each. Viability and germination tests were conducted using freshly fallen seeds and seeds stored for five months. Morphologically the seeds of A. colubrina var. cebil are circular to subcircular, laterally compressed, smooth, bright brown and have a horseshoe fissure line (= pleurogram) on both sides. The seed coat comprises five tissue layers and a double (external and internal) cuticle. The outer cuticle (on the epidermis) is smooth and interrupted by microcracks and pores of variable depth. The epidermis consists of macroesclereids with non-lignified secondary walls. This layer is separated from the underlying ones during seed hydration. The other layers of internal tissues are comprised of osteosclereids, parenchyma, osteosclereids, and macrosclereids. The percentage of viable seeds was 93%, decreasing to 75% in seeds with five months old. Seed mass increased 76% after the first eight hours of hydration. Germination percentage was 75% after 76 hours. Germination of seeds stored for five

Evaluation of pollen viability, stigma receptivity and fertilization ...

African Journals Online (AJOL)

AJL

2013-11-13

Nov 13, 2013 ... by field artificial pollination were analyzed in this study. The maximum pollen viability .... the day before anthesis to avoid self-pollination. Subsequently, between ..... The Lagerstroemia handbook/checklist. Ameri. Association ...

Viability of Event Management Business in Batangas City, Philippine: Basis for Business Operation Initiatives

OpenAIRE

Jeninah Christia D. Borbon

2016-01-01

The research study on Viability of Event Management Business in Batangas City: Basis for Business Operation Initiatives aimed to assess the viability of this type of business using Thompson’s (2005) Dimension of Business Viability as its tool in order to create business operation initiatives. It provided a good framework for defining success factors in entrepreneurial operation initiatives in a specific business type – event management. This study utilized event organizers based i...

Viability of Green Roofs as a Flood Mitigation Element in the Central Region of Chile

Directory of Open Access Journals (Sweden)

Daniel Mora-Melià

2018-04-01

Full Text Available Population increase and urban development over the last 20 years in Chile have outgrown most rainwater drainage and evacuation systems. Many cities located in the central region suffer from frequent floods in some of their sectors during winter rainfall events. In addition, the lack of green spaces in these cities leads to biodiversity loss, increasing temperatures, greater energy demands, etc. Green roofs offer a solution that can mitigate climate change by reducing the runoff in cities with extensive, highly impermeable areas. This work analyses the installation of green roofs as a potential solution to the sectorial floods suffered by many cities in central Chile. The methodology includes the identification of conflictive sectors in the city of Curicó, hydrological modelling with the Storm Water Management Model (SWMM software, the consideration of different distributions and types of green roof surfaces, and computational simulations to determine the feasibility of green roofs for preventing floods. The results show that, for moderate rainfall events, all studied sectors could avoid flooding if at least 50% of the surrounding area had green roofs (irrespective of the type of green roof. In contrast, in the presence of strong rainfall events, only some semi-extensive and extensive green roofs covering 60% to 95% of the surrounding area, respectively, could prevent flooding.

Molecular genetics of rhodopsin and phototrans duction in the visual system of Drosophila

International Nuclear Information System (INIS)

Zuker, C.; Cowman, A.; Montell, C.; Rubin, G.

1987-01-01

The authors have isolated the genes encoding four Drosophila visual pigments. Each of these opsins is expressed in a set of functionally and anatomically distinct photoreceptor cells of the eye. One is expressed in the six outer photoreceptor cells (R1-R6), the second in the central R8 photoreceptor cell, and the other two in the UV sensitive R7 photoreceptor cells. They have determined the structure and nucleotide sequence of each of these genes. They have used P element-mediated gene transfer to introduce the cloned structural gene for the R1-R6 opsin in the Drosophila germline and restored the ninaE mutant phenotype to wild-type. In an attempt to study the contribution of the various opsins to the specific functional properties of the different photoreceptor cell types, they have genetically engineered Drosophila lines that express R8 opsin in the R1-R6 photoreceptor cells. In collaboration with Drs. Ozaki and Pak at Purdue University, they have used oligonucleotide site-directed mutagenesis to mutate selected amino acids and regions of the rhodopsin molecule and reintroduced the mutated genes into Drosophila to analyze structure-function relationships in the rhodopsin molecule

Imaging of tumor viability in lung cancer. Initial results using 23Na-MRI

International Nuclear Information System (INIS)

Henzler, T.; Apfaltrer, P.; Haneder, S.; Schoenberg, S.O.; Fink, C.; Konstandin, S.; Schad, L.; Schmid-Bindert, G.; Manegold, C.; Wenz, F.

2012-01-01

23 Na-MRI has been proposed as a potential imaging biomarker for the assessment of tumor viability and the evaluation of therapy response but has not yet been evaluated in patients with lung cancer. We aimed to assess the feasibility of 23 Na-MRI in patients with lung cancer. Three patients with stage IV adenocarcinoma of the lung were examined on a clinical 3 Tesla MRI system (Magnetom TimTrio, Siemens Healthcare, Erlangen, Germany). Feasibility of 23 Na-MRI images was proven by comparison and fusion of 23 Na-MRI with 1 H-MR, CT and FDG-PET-CT images. 23 Na signal intensities (SI) of tumor and cerebrospinal fluid (CSF) of the spinal canal were measured and the SI ratio in tumor and CSF was calculated. One chemonaive patient was examined before and after the initiation of combination therapy (Carboplatin, Gemcitabin, Cetuximab). All 23 Na-MRI examinations were successfully completed and were of diagnostic quality. Fusion of 23 Na-MRI images with 1 H-MRI, CT and FDG-PET-CT was feasible in all patients and showed differences in solid and necrotic tumor areas. The mean tumor SI and the tumor/CSF SI ratio were 13.3 ± 1.8 x 103 and 0.83 ± 0.14, respectively. In necrotic tumors, as suggested by central non-FDG-avid areas, the mean tumor SI and the tumor/CSF ratio were 19.4 x 103 and 1.10, respectively. 23 Na-MRI is feasible in patients with lung cancer and could provide valuable functional molecular information regarding tumor viability, and potentially treatment response. (orig.)

The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by 15O-water-PET

International Nuclear Information System (INIS)

Tsukagoshi, Joichi

1994-01-01

The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by 15 O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with 15 O-water even in the absence of metabolic imaging. (author)

Assessing Photoreceptor Structure in Retinitis Pigmentosa and Usher Syndrome.

Science.gov (United States)

Sun, Lynn W; Johnson, Ryan D; Langlo, Christopher S; Cooper, Robert F; Razeen, Moataz M; Russillo, Madia C; Dubra, Alfredo; Connor, Thomas B; Han, Dennis P; Pennesi, Mark E; Kay, Christine N; Weinberg, David V; Stepien, Kimberly E; Carroll, Joseph

2016-05-01

The purpose of this study was to examine cone photoreceptor structure in retinitis pigmentosa (RP) and Usher syndrome using confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). Nineteen subjects (11 RP, 8 Usher syndrome) underwent ophthalmic and genetic testing, spectral-domain optical coherence tomography (SD-OCT), and AOSLO imaging. Split-detector images obtained in 11 subjects (7 RP, 4 Usher syndrome) were used to assess remnant cone structure in areas of altered cone reflectivity on confocal AOSLO. Despite normal interdigitation zone and ellipsoid zone appearance on OCT, foveal and parafoveal cone densities derived from confocal AOSLO images were significantly lower in Usher syndrome compared with RP. This was due in large part to an increased prevalence of non-waveguiding cones in the Usher syndrome retina. Although significantly correlated to best-corrected visual acuity and foveal sensitivity, cone density can decrease by nearly 38% before visual acuity becomes abnormal. Aberrantly waveguiding cones were noted within the transition zone of all eyes and corresponded to intact inner segment structures. These remnant cones decreased in density and increased in diameter across the transition zone and disappeared with external limiting membrane collapse. Foveal cone density can be decreased in RP and Usher syndrome before visible changes on OCT or a decline in visual function. Thus, AOSLO imaging may allow more sensitive monitoring of disease than current methods. However, confocal AOSLO is limited by dependence on cone waveguiding, whereas split-detector AOSLO offers unambiguous and quantifiable visualization of remnant cone inner segment structure. Confocal and split-detector thus offer complementary insights into retinal pathology.

Echinococcus metacestode: in search of viability markers.

Science.gov (United States)

Gottstein, Bruno; Wang, Junhua; Blagosklonov, Oleg; Grenouillet, Frédéric; Millon, Laurence; Vuitton, Dominique A; Müller, Norbert

2014-01-01

Epidemiological studies have demonstrated that most humans infected with Echinococcus spp. exhibit resistance to disease. When infection leads to disease, the parasite is partially controlled by host immunity: in case of immunocompetence, the normal alveolar echinococcosis (AE) or cystic echinococcosis (CE) situation, the metacestode grows slowly, and first clinical signs appear years after infection; in case of impaired immunity (AIDS; other immunodeficiencies), uncontrolled proliferation of the metacestode leads to rapidly progressing disease. Assessing Echinococcus multilocularis viability in vivo following therapeutic interventions in AE patients may be of tremendous benefit when compared with the invasive procedures used to perform biopsies. Current options are F18-fluorodeoxyglucose-positron emission tomography (FDG-PET), which visualizes periparasitic inflammation due to the metabolic activity of the metacestode, and measurement of antibodies against recEm18, a viability-associated protein, that rapidly regresses upon metacestode inactivation. For Echinococcus granulosus, similar prognosis-associated follow-up parameters are still lacking but a few candidates may be listed. Other possible markers include functional and diffusion-weighted Magnetic Resonance Imaging (MRI), and measurement of products from the parasite (circulating antigens or DNA), and from the host (inflammation markers, cytokines, or chemokines). Even though some of them have been promising in pilot studies, none has been properly validated in an appropriate number of patients until now to be recommended for further use in clinical settings. There is therefore still a need to develop reliable tools for improved viability assessment to provide the sufficient information needed to reliably withdraw anti-parasite benzimidazole chemotherapy, and a basis for the development of new alternative therapeutic tools. © B. Gottstein et al., published by EDP Sciences, 2014.

Radiopeptide internalisation and externalization assays: cell viability and radioligand integrity.

Science.gov (United States)

Naqvi, Syed Ali Raza; Sosabowski, Jane K; Nagra, Saeed Ahamad; Ishfaq, Malik M; Mather, Stephen J; Matzow, Torkjel

2011-01-01

Various aspects of radiopeptide receptor-mediated cell internalisation and externalization assays were assessed, including the integrity of externalized peptides and the effect of varying the pH and incubation time of the acid wash step (to remove surface receptor-bound ligand) on efficacy and cell viability. The observed intact proportion of externalized peptide was 5-10%, and acid wash buffers with pH 2.8 or below were found to be detrimental to cell viability and integrity, particularly following prolonged incubation times. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effects induced on the transverse-spatial-impulse response of an inhomogeneous photoreceptor with a nonsymmetric refractive index profile and arbitrarily located origin

International Nuclear Information System (INIS)

Calvo, M.L.

1987-01-01

In a few earlier communications, spatial-transverse-impulse response (STIR) associated with the initial field transversely distributed across the entrance pupil of an inhomogeneous optical wave guide (photo-receptor) has been investigated. In the present work, effects of indetermination in the location of the origin on an arbitrarily defined refractive index profile, representing the degree of inhomogenity at the aperture pupil of a single receptor, have been studied. Some consequences related to a few possible technical applications have been discussed

The two parallel photocycles of the Chlamydomonas sensory photoreceptor histidine kinase rhodopsin 1.

Science.gov (United States)

Luck, Meike; Hegemann, Peter

2017-10-01

Histidine kinase rhodopsins (HKRs) belong to a class of unexplored sensory photoreceptors that share a similar modular architecture. The light sensing rhodopsin domain is covalently linked to signal-transducing modules and in some cases to a C-terminal guanylyl-cyclase effector. In spite of their wide distribution in unicellular organisms, very little is known about their physiological role and mechanistic functioning. We investigated the photochemical properties of the recombinant rhodopsin-fragment of Cr-HKR1 originating from Chlamydomonas reinhardtii. Our spectroscopic studies revealed an unusual thermal stability of the photoproducts with the deprotonated retinal Schiff base (RSB). Upon UV-irradiation these Rh-UV states with maximal absorbance in the UVA-region (Rh-UV) photochemically convert to stable blue light absorbing rhodopsin (Rh-Bl) with protonated chromophore. The heterogeneity of the sample is based on two parallel photocycles with the chromophore in C 15 =N-syn- or -anti-configuration. This report represents an attempt to decipher the underlying reaction schemes and interconversions of the two coexisting photocycles. Copyright © 2017 Elsevier GmbH. All rights reserved.

Effect of late-stage therapy on disease progression in AAV-mediated rescue of photoreceptor cells in the retinoschisin-deficient mouse.

Science.gov (United States)

Janssen, Andreas; Min, Seok H; Molday, Laurie L; Tanimoto, Naoyuki; Seeliger, Mathias W; Hauswirth, William W; Molday, Robert S; Weber, Bernhard H F

2008-06-01

Proof-of-concept for a successful adeno-associated virus serotype 5 (AAV5)-mediated gene therapy in X-linked juvenile retinoschisis (XLRS) has been demonstrated in an established mouse model for this condition. The initial studies concentrated on early time-points of treatment. In this study, we aimed to explore the consequences of single subretinal injections administered at various stages of more advanced disease. By electroretinogram (ERG), functional improvement in treated versus untreated eyes is found to be significant in retinoschisin-deficient mice injected at the time-points of 15 days (P15), 1 month (PM1), and 2 months (PM2) after birth. In mice treated at 7 months after birth (PM7), an age previously shown to exhibit advanced retinal disease, ERG responses reveal no beneficial effects of vector treatment. Generally, functional rescue is paralleled by sustained retinoschisin expression and significant photoreceptor survival relative to untreated eyes. Quantitative measures of photoreceptors and peanut agglutinin-labeled ribbon synapses demonstrate rescue effects even in mice injected as late as PM7. Taken together, AAV5-mediated gene replacement is beneficial in slowing disease progression in murine XLRS. In addition, we show the effectiveness of rescue efforts even if treatment is delayed until advanced signs of disease have developed. Human XLRS patients might benefit from these findings, which suggest that the effectiveness of treatment appears not to be restricted to the early stages of the disease, and that treatment may prove to be valuable even when administered at more advanced stages.

The role of adrenergic activation on murine luteal cell viability and progesterone production.

Science.gov (United States)

Wang, Jing; Tang, Min; Jiang, Huaide; Wu, Bing; Cai, Wei; Hu, Chuan; Bao, Riqiang; Dong, Qiming; Xiao, Li; Li, Gang; Zhang, Chunping

2016-09-15

Sympathetic innervations exist in mammalian CL. The action of catecholaminergic system on luteal cells has been the focus of a variety of studies. Norepinephrine (NE) increased progesterone secretion of cattle luteal cells by activating β-adrenoceptors. In this study, murine luteal cells were treated with NE and isoprenaline (ISO). We found that NE increased the viability of murine luteal cells and ISO decreased the viability of luteal cells. Both NE and ISO promoted the progesterone production. Nonselective β-adrenergic antagonist, propranolol reversed the effect of ISO on cell viability but did not reverse the effect of NE on cell viability. Propranolol blocked the influence of NE and ISO on progesterone production. These results reveal that the increase of luteal cell viability induced by NE is not dependent on β-adrenergic activation. α-Adrenergic activation possibly contributes to it. Both NE and ISO increased progesterone production through activating β-adrenergic receptor. Further study showed that CyclinD2 is involved in the increase of luteal cell induced by NE. 3β-Hydroxysteroid dehydrogenase, LHR, steroidogenic acute regulatory protein (StAR), and PGF2α contribute to the progesterone production induced by NE and ISO. Copyright © 2016 Elsevier Inc. All rights reserved.

Viability of Lactobacillus acidophilus and Lactobacillus casei in fermented milk products during refrigerated storage.

Science.gov (United States)

Nighswonger, B D; Brashears, M M; Gilliland, S E

1996-02-01

The viability was investigated of five strains of Lactobacillus acidophilus and one strain of Lactobacillus casei that were added as adjuncts to yogurt and cultured buttermilk during 28 d of refrigerated storage at 5 to 7 degrees C. A modification of LBS (Lactobacillus selection) agar was used for the enumeration of L. acidophilus and L. casei. The medium allowed the colony formation of the adjunct bacteria while preventing colony formation of the traditional yogurt or buttermilk starter cultures. At each sampling period, colonies from the selective agar medium were isolated for confirmation of identity to confirm that only L. acidophilus and L. casei were enumerated, that their characteristics did not change during storage, or both. The strains of L. acidophilus varied in both cultured products. In buttermilk, L. acidophilus MUH-41, O-16, and L-1 exhibited no significant loss in viability, but strains 43121 and La-5 did. No significant loss in viability of L. acidophilus MUH-41 and L-1 occurred in yogurt prepared using culture CM2; however, strains 43121, O-16, and La-5 lost viability. In the yogurt prepared using culture YC-4, L. acidophilus 43121 exhibited no significant loss in viability, but MUH-41, O-16, L-1, and La-5 did. There was no loss in viability of L. casei GG during storage of any of the cultured products.

Analysis of the function of the photoreceptors phytochrome B and phytochrome D in Nicotiana plumbaginifolia and Arabidopsis thaliana.

Science.gov (United States)

Fernández, Aurora Piñas; Gil, Patricia; Valkai, Ildiko; Nagy, Ferenc; Schäfer, Eberhard

2005-05-01

To investigate the mechanism of phytochrome action in vivo, NtPHYB, AtPHYB and phyD:green fluorescent protein (GFP) were overexpressed in Nicotiana plumbaginifolia and Arabidopsis thaliana. The expression of 35S:NtPHYB:GFP and 35S:AtPHYB:GFP complemented the tobacco hgl2 and Arabidopsis phyB-9 mutations, whereas the 35S:AtPHYD:GFP only rescued the hgl2 mutant. All three fusion proteins are transported into the nucleus in all genetic backgrounds. These data indicate that AtPHYD:GFP is biologically active and functions as the main red light receptor in transgenic tobacco, and establish an experimental system for the functional analysis of this elusive photoreceptor in vivo.

Viability of lactobacillus acidophilus in various vaginal tablet formulations

Directory of Open Access Journals (Sweden)

Fazeli M.R.

2006-07-01

Full Text Available The lactobacilli which are present in vaginal fluids play an important role in prevention of vaginosis and there are considerable interests in formulation of these friendly bacteria into suitable pharmaceutical dosage forms. Formulating these microorganisms for vaginal application is a critical issue as the products should retain viability of lactobacilli during formulation and also storage. The aim of this study was to examine the viability and release of Lactobacillus acidophilus from slow-release vaginal tablets prepared by using six different retarding polymers and from two effervescent tablets prepared by using citric or adipic acid. The Carbomer–based formulations showed high initial viablility compared to those based on HPMC-LV, HPMC-HV, Polycarbophil and SCMC polymers which showed one log decrease in viable cells. All retarding polymers in slow release formulations presented a strong bacterial release at about 2 h except Carbomer polymers which showed to be poor bacterial releasers. Although effervescent formulations produced a quick bacterial release in comparison with polymer based slow-release tablets, they were less stable in cold storage. Due to the strong chelating characteristic of citric acid, the viability was quickly lost for aqueous medium of citric acid in comparison with adipic acid based effervescent tablets.

Hospital board effectiveness: relationships between board training and hospital financial viability.

Science.gov (United States)

Molinari, C; Morlock, L; Alexander, J; Lyles, C A

1992-01-01

This study examined whether hospital governing boards that invest in board education and training are more informed and effective decision-making bodies. Measures of hospital financial viability (i.e., selected financial ratios and outcomes) are used as indicators of hospital board effectiveness. Board participation in educational programs was significantly associated with improved profitability, liquidity, and occupancy levels, suggesting that investment in the education of directors is likely to enhance hospital viability and thus increase board effectiveness.

Laser solder welding of articular cartilage: tensile strength and chondrocyte viability.

Science.gov (United States)

Züger, B J; Ott, B; Mainil-Varlet, P; Schaffner, T; Clémence, J F; Weber, H P; Frenz, M

2001-01-01

The surgical treatment of full-thickness cartilage defects in the knee joint remains a therapeutic challenge. Recently, new techniques for articular cartilage transplantation, such as mosaicplasty, have become available for cartilage repair. The long-term success of these techniques, however, depends not only on the chondrocyte viability but also on a lateral integration of the implant. The goal of this study was to evaluate the feasibility of cartilage welding by using albumin solder that was dye-enhanced to allow coagulation with 808-nm laser diode irradiation. Conventional histology of light microscopy was compared with a viability staining to precisely determine the extent of thermal damage after laser welding. Indocyanine green (ICG) enhanced albumin solder (25% albumin, 0.5% HA, 0.1% ICG) was used for articular cartilage welding. For coagulation, the solder was irradiated through the cartilage implant by 808-nm laser light and the tensile strength of the weld was measured. Viability staining revealed a thermal damage of typically 500 m in depth at an irradiance of approximately 10 W/cm(2) for 8 seconds, whereas conventional histologies showed only half of the extent found by the viability test. Heat-bath investigations revealed a threshold temperature of minimum 54 degrees C for thermal damage of chondrocytes. Efficient cartilage bonding was obtained by using bovine albumin solder as adhesive. Maximum tensile strength of more than 10 N/cm(2) was achieved. Viability tests revealed that the thermal damage is much greater (up to twice) than expected after light microscopic characterization. This study shows the feasibility to strongly laser weld cartilage on cartilage by use of a dye-enhanced albumin solder. Possibilities to reduce the range of damage are suggested. Copyright 2001 Wiley-Liss, Inc.

Communication Departments in (Pro) Action: A Case Study of an On-Campus Mini-Conference To Address Concerns about the Quality, Centrality and Viability of the Communication Major.

Science.gov (United States)

Everett, Marcia; Rudd, Andrew E.

The National Communication Association's Assessment Packet identified divisions between and among sub-fields of communication as threatening the viability of departments on many campuses and possibly even the integrity of the discipline. In 2000 James Applegate advocated in "Spectra" the importance of unity for developing a strong…

Optimizing cell viability in droplet-based cell deposition

NARCIS (Netherlands)

Hendriks, Jan; Visser, C.W.; Henke, S.J.; Leijten, Jeroen Christianus Hermanus; Saris, Daniël B.F.; Sun, Chao; Lohse, Detlef; Karperien, Hermanus Bernardus Johannes

2015-01-01

Biofabrication commonly involves the use of liquid droplets to transport cells to the printed structure. However, the viability of the cells after impact is poorly controlled and understood, hampering applications including cell spraying, inkjet bioprinting, and laser-assisted cell transfer. Here,

Two types of Tet-On transgenic lines for doxycycline-inducible gene expression in zebrafish rod photoreceptors and a gateway-based tet-on toolkit.

Directory of Open Access Journals (Sweden)

Leah J Campbell

Full Text Available The ability to control transgene expression within specific tissues is an important tool for studying the molecular and cellular mechanisms of development, physiology, and disease. We developed a Tet-On system for spatial and temporal control of transgene expression in zebrafish rod photoreceptors. We generated two transgenic lines using the Xenopus rhodopsin promoter to drive the reverse tetracycline-controlled transcriptional transactivator (rtTA, one with self-reporting GFP activity and one with an epitope tagged rtTA. The self-reporting line includes a tetracycline response element (TRE-driven GFP and, in the presence of doxycycline, expresses GFP in larval and adult rods. A time-course of doxycycline treatment demonstrates that maximal induction of GFP expression, as determined by the number of GFP-positive rods, is reached within approximately 24 hours of drug treatment. The epitope-tagged transgenic line eliminates the need for the self-reporting GFP activity by expressing a FLAG-tagged rtTA protein. Both lines demonstrate strong induction of TRE-driven transgenes from plasmids microinjected into one-cell embryos. These results show that spatial and temporal control of transgene expression can be achieved in rod photoreceptors. Additionally, system components are constructed in Gateway compatible vectors for the rapid cloning of doxycycline-inducible transgenes and use in other areas of zebrafish research.

In vitro germination and viability of pollen grain of coconut accessions1

Directory of Open Access Journals (Sweden)

Catrine Regina Feitosa Moura

Full Text Available Storage as a means of maintaining the pollen viability is important for the preservation of the genetic variability, facilitates the exchange of germplasm and greatly contributes to the generation of variability obtained from artificial crosses, increasing the efficiency of breeding programs. The objective of this study was to select different culture media for the in vitro germination of pollen grain of dwarf and tall coconut accessions, as well as to determine the viability of pollen grain at room temperature conditions. For this purpose, Brazil Green Dwarf (BGD and Brazilian Tall (BRA pollen grains derived from the Coconut Active Germplasm Bank of Embrapa Coastal Tablelands Sergipe were used. To evaluate the effect of different culture media on the in vitro germination of pollen grains of anão verde do Brasil de Jiqui (AVeBrJ and gigante do Brasil Praia do Forte (GBrPF accessions, they were inoculated on to Petri dishes containing 2 ml of culture media. The pollen viability was assessed by staining with 1% acetic carmine and in vitro germination at 0, 24, 48 and 72 hours. The culture medium of Lora is suitable to assess the in vitrogermination of pollen grain of the AVeBrJ and GBrPF accessions. The pollen grain of the AVeBrJ accession showed intermediate viability (66.87% at room temperature up to 23.14 hours by in vitro germination. The pollen grain of the GBrPF accession showed high viability, above 70%, at room temperature up to 120 hours by in vitro germination.

Is cell viability always directly related to corrosion resistance of stainless steels?

Science.gov (United States)

Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

2016-05-01

It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. Copyright © 2016 Elsevier B.V. All rights reserved.

Tissue viability monitoring: a multi-sensor wearable platform approach

Science.gov (United States)

Mathur, Neha; Davidson, Alan; Buis, Arjan; Glesk, Ivan

2016-12-01

Health services worldwide are seeking ways to improve patient care for amputees suffering from diabetes, and at the same time reduce costs. The monitoring of residual limb temperature, interface pressure and gait can be a useful indicator of tissue viability in lower limb amputees especially to predict the occurrence of pressure ulcers. This is further exacerbated by elevated temperatures and humid micro environment within the prosthesis which encourages the growth of bacteria and skin breakdown. Wearable systems for prosthetic users have to be designed such that the sensors are minimally obtrusive and reliable enough to faithfully record movement and physiological signals. A mobile sensor platform has been developed for use with the lower limb prosthetic users. This system uses an Arduino board that includes sensors for temperature, gait, orientation and pressure measurements. The platform transmits sensor data to a central health authority database server infrastructure through the Bluetooth protocol at a suitable sampling rate. The data-sets recorded using these systems are then processed using machine learning algorithms to extract clinically relevant information from the data. Where a sensor threshold is reached a warning signal can be sent wirelessly together with the relevant data to the patient and appropriate medical personnel. This knowledge is also useful in establishing biomarkers related to a possible deterioration in a patient's health or for assessing the impact of clinical interventions.

Potential carbon credit and community expectations towards viability ...

African Journals Online (AJOL)

Nicholaus family

marginal (incremental) revenues from forest carbon stock as well as the conceptual trend of forest biomass indicates that, there is ... Key words: Carbon stock payments, community preferences and REDD+ project viability. INTRODUCTION .... following criteria were used in selecting respondents especially households: 1) ...

Study progress of cardiac MRI technology in assessment of myocardial viability after myocardial infarction

International Nuclear Information System (INIS)

Wang Jing; Zhang Hao

2013-01-01

Acute myocardial infarction (AMI) is one of the most common diseases that cause disability and death around the world. Correctly and effectively assessing the myocardial viability after myocardial infarction can reduce the disabled rate and mortality rate. At present, many methods could be used to assess myocardial viability. The cardiac magnetic resonance imaging (CMR) technology has a lot of advantages compared to other methods. In this paper, we reviewed the research progress of CMR in assessment of myocardial viability after myocardial infarction, and compared CMR with other technologies. (authors)

Study of wettability and cell viability of H implanted stainless steel

Science.gov (United States)

Shafique, Muhammad Ahsan; Ahmad, Riaz; Rehman, Ihtesham Ur

2018-03-01

In the present work, the effect of hydrogen ion implantation on surface wettability and biocompatibility of stainless steel is investigated. Hydrogen ions are implanted in the near-surface of stainless steel to facilitate hydrogen bonding at different doses with constant energy of 500 KeV, which consequently improve the surface wettability. Treated and untreated sample are characterized for surface wettability, incubation of hydroxyapatite and cell viability. Contact angle (CA) study reveals that surface wettability increases with increasing H-ion dose. Raman spectroscopy shows that precipitation of hydroxyapatite over the surface increase with increasing dose of H-ions. Cell viability study using MTT assay describes improved cell viability in treated samples as compared to the untreated sample. It is found that low dose of H-ions is more effective for cell proliferation and the cell count decreases with increasing ion dose. Our study demonstrates that H ion implantation improves the surface wettability and biocompatibility of stainless steel.

Viability Tests for Fresh and Stored Haemopoietic Cells

Energy Technology Data Exchange (ETDEWEB)

Fliedner, T. M. [Abteilung fuer klinische Physiologie, Zentrum fuer Klinische Grundlagenforschung, Universitaet Ulm, Ulm, Federal Republic of Germany (Germany)

1969-07-15

This paper reviews current methods of measurement of the viability of fresh and stored haemopoietic cells. The life expectancy of granulocytes and monocytes after transfusion can be studied by in-vitro labelling with {sup 3}H-DFP and subsequent autoradiography. The evaluation of data in about 30 patients with various haemopoietic conditions indicates a wide variation of the disappearance half-time of granulocytes. {sup 3}H-cytidine labels essentially all lymphocytes in vitro, predominantly in their RNA. Transfusion of {sup 3}H-cytidine-labelled lymphocytes enables one to measure the lower limit of their life-expectancy as well as their rate of RNA metabolism. If bone-marrow cells are labelled in vitro with {sup 3}H-thymidine and subsequently transfused, their capability to circulate, to reach the haemopoietic tissue of the host, to proliferate and to mature can be demonstrated. However, the repopulating capacity of frozen and thawed marrow is independent of the ability of {sup 3}H-TDR-labelled marrow cells to circulate, proliferate and mature. It is assumed that bone-marrow cells capable of repopulating depleted haemopoietic tissue are resting under steady-state conditions and can be labelled by means of {sup 3}H-TDR only using special conditions. Thus the only viability tests for fresh and stored bone-marrow cells at present appear to be bioassay methods at the animal experimental level. The results indicate the need for the development of reliable viability tests for stem cells applicable in both experimental and clinical conditions. (author)

Role of Autofluorescence in Inflammatory/Infective Diseases of the Retina and Choroid

OpenAIRE

Samy, Ahmed; Lightman, Sue; Ismetova, Filis; Talat, Lazha; Tomkins-Netzer, Oren

2014-01-01

Fundus autofluorescence (FAF) has recently emerged as a novel noninvasive imaging technique that uses the fluorescent properties of innate fluorophores accumulated in the retinal pigment epithelium (RPE) to assess the health and viability of the RPE/photoreceptor complex. Recent case reports suggest FAF as a promising tool for monitoring eyes with posterior uveitis helping to predict final visual outcome. In this paper we review the published literature on FAF in these disorders, specifically...

Morphological variability, lectin binding and Na+,K+-activated adenosine triphosphatase activity of isolated Müller (glial) cells from the rabbit retina.

Science.gov (United States)

Reichenbach, A; Dettmer, D; Brückner, G; Neumann, M; Birkenmeyer, G

1985-03-22

Rabbit retinal Müller cells were isolated by means of papaine and mechanical dissociation. These cells were shown to have a well preserved morphology and to preserve viability for many hours. Intense wheat germ agglutinin binding occurs on the photoreceptor side of Müller cells, especially in the microvillous region. Rabbit retinal Müller cells have a Na+,K+-activated adenosine triphosphatase activity in the same order of magnitude as brain astroglial cells.

Knocking Down Snrnp200 Initiates Demorphogenesis of Rod Photoreceptors in Zebrafish

Directory of Open Access Journals (Sweden)

Yuan Liu

2015-01-01

Full Text Available Purpose. The small nuclear ribonucleoprotein 200 kDa (SNRNP200 gene is a fundamental component for precursor message RNA (pre-mRNA splicing and has been implicated in the etiology of autosomal dominant retinitis pigmentosa (adRP. This study aims to determine the consequences of knocking down Snrnp200 in zebrafish. Methods. Expression of the Snrnp200 transcript in zebrafish was determined via whole mount in situ hybridization. Morpholino oligonucleotide (MO aiming to knock down the expression of Snrnp200 was injected into zebrafish embryos, followed by analyses of aberrant splicing and expression of the U4/U6-U5 tri-small nuclear ribonucleoproteins (snRNPs components and retina-specific transcripts. Systemic changes and retinal phenotypes were further characterized by histological study and immunofluorescence staining. Results. Snrnp200 was ubiquitously expressed in zebrafish. Knocking down Snrnp200 in zebrafish triggered aberrant splicing of the cbln1 gene, upregulation of other U4/U6-U5 tri-snRNP components, and downregulation of a panel of retina-specific transcripts. Systemic defects were found correlated with knockdown of Snrnp200 in zebrafish. Only demorphogenesis of rod photoreceptors was detected in the initial stage, mimicking the disease characteristics of RP. Conclusions. We conclude that knocking down Snrnp200 in zebrafish could alter regular splicing and expression of a panel of genes, which may eventually trigger rod defects.

From "Gut Feeling" to Objectivity: Machine Preservation of the Liver as a Tool to Assess Organ Viability.

Science.gov (United States)

Watson, Christopher J E; Jochmans, Ina

2018-01-01

The purpose of this review was to summarise how machine perfusion could contribute to viability assessment of donor livers. In both hypothermic and normothermic machine perfusion, perfusate transaminase measurement has allowed pretransplant assessment of hepatocellular damage. Hypothermic perfusion permits transplantation of marginal grafts but as yet has not permitted formal viability assessment. Livers undergoing normothermic perfusion have been investigated using parameters similar to those used to evaluate the liver in vivo. Lactate clearance, glucose evolution and pH regulation during normothermic perfusion seem promising measures of viability. In addition, bile chemistry might inform on cholangiocyte viability and the likelihood of post-transplant cholangiopathy. While the use of machine perfusion technology has the potential to reduce and even remove uncertainty regarding liver graft viability, analysis of large datasets, such as those derived from large multicenter trials of machine perfusion, are needed to provide sufficient information to enable viability parameters to be defined and validated .

Tychastic measure of viability risk

CERN Document Server

Aubin, Jean-Pierre; Dordan, Olivier

2014-01-01

This book presents a forecasting mechanism of the price intervals for deriving the SCR (solvency capital requirement) eradicating the risk during the exercise period on one hand, and measuring the risk by computing the hedging exit time function associating with smaller investments the date until which the value of the portfolio hedges the liabilities on the other. This information, summarized under the term “tychastic viability measure of risk” is an evolutionary alternative to statistical measures, when dealing with evolutions under uncertainty. The book is written by experts in the field and the target audience primarily comprises research experts and practitioners.

The Effect of zeolite addition on viability of paddy straw mushroom spawn

Directory of Open Access Journals (Sweden)

DJUMHAWAN RATMAN PERMANA

2007-01-01

Full Text Available The objective of this research was to increase the viability of the paddy straw mushroom spawn by adding natural stone on the media’s composition for the paddy straw mushroom spawn. Mycelium of the paddy straw mushroom was take from the pure development of the paddy straw mushroom which was planted on the various treatment for media e.i. 100% cotton media and rice bran + 0% zeolite (A, 75% cotton media and rice bran + 25% zeolite (B, 50% cotton media and rice bran + 50% zeolite (C, 25% cotton and rice bran + 75% zeolite (D, 0% cotton media and rice bran + 100% rice bran (E. Each treatment was observed for the length of mycelium, the concentration of reduced sugar, total carbon and water content, spawn media weight, pH and temperature. Results demonstrated that there is a positive effect of zeolite added to the paddy straw mushroom media. The zeolite able to adsorbed nutrient through its pores, so the mycelium of the paddy straw mushroom able to use the nutrient gradually and equally appropriate with its growth. Therefore the viability of the paddy straw mushroom is increase. Result showed that the B is the best viability in the Potetos Dectrose Agar (PDA media, that has viability power up to 50 days after inoculation and the temperature are 29,6 0C, then followed by treatment C, D, A and E, each has viability power up to 42; 38; 34; 22 days after inoculation and the maximum length of each mycelium are 17.5; 9.2; 0.9; 0.5 cm, but in the treatment D being contaminated by Aspergillus sp.

Nanodiamonds on tetrahedral amorphous carbon significantly enhance dopamine detection and cell viability.

Science.gov (United States)

Peltola, Emilia; Wester, Niklas; Holt, Katherine B; Johansson, Leena-Sisko; Koskinen, Jari; Myllymäki, Vesa; Laurila, Tomi

2017-02-15

We hypothesize that by using integrated carbon nanostructures on tetrahedral amorphous carbon (ta-C), it is possible to take the performance and characteristics of these bioelectrodes to a completely new level. The integrated carbon electrodes were realized by combining nanodiamonds (NDs) with ta-C thin films coated on Ti-coated Si-substrates. NDs were functionalized with mixture of carboxyl and amine groups ND andante or amine ND amine , carboxyl ND vox or hydroxyl groups ND H and drop-casted or spray-coated onto substrate. By utilizing these novel structures we show that (i) the detection limit for dopamine can be improved by two orders of magnitude [from 10µM to 50nM] in comparison to ta-C thin film electrodes and (ii) the coating method significantly affects electrochemical properties of NDs and (iii) the ND coatings selectively promote cell viability. ND andante and ND H showed most promising electrochemical properties. The viability of human mesenchymal stem cells and osteoblastic SaOS-2 cells was increased on all ND surfaces, whereas the viability of mouse neural stem cells and rat neuroblastic cells was improved on ND andante and ND H and reduced on ND amine and ND vox. The viability of C6 cells remained unchanged, indicating that these surfaces will not cause excess gliosis. In summary, we demonstrated here that by using functionalized NDs on ta-C thin films we can significantly improve sensitivity towards dopamine as well as selectively promote cell viability. Thus, these novel carbon nanostructures provide an interesting concept for development of various in vivo targeted sensor solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

The GTP- and Phospholipid-Binding Protein TTD14 Regulates Trafficking of the TRPL Ion Channel in Drosophila Photoreceptor Cells

Science.gov (United States)

Cerny, Alexander C.; Altendorfer, André; Schopf, Krystina; Baltner, Karla; Maag, Nathalie; Sehn, Elisabeth; Wolfrum, Uwe; Huber, Armin

2015-01-01

Recycling of signaling proteins is a common phenomenon in diverse signaling pathways. In photoreceptors of Drosophila, light absorption by rhodopsin triggers a phospholipase Cβ-mediated opening of the ion channels transient receptor potential (TRP) and TRP-like (TRPL) and generates the visual response. The signaling proteins are located in a plasma membrane compartment called rhabdomere. The major rhodopsin (Rh1) and TRP are predominantly localized in the rhabdomere in light and darkness. In contrast, TRPL translocates between the rhabdomeral plasma membrane in the dark and a storage compartment in the cell body in the light, from where it can be recycled to the plasma membrane upon subsequent dark adaptation. Here, we identified the gene mutated in trpl translocation defective 14 (ttd14), which is required for both TRPL internalization from the rhabdomere in the light and recycling of TRPL back to the rhabdomere in the dark. TTD14 is highly conserved in invertebrates and binds GTP in vitro. The ttd14 mutation alters a conserved proline residue (P75L) in the GTP-binding domain and abolishes binding to GTP. This indicates that GTP binding is essential for TTD14 function. TTD14 is a cytosolic protein and binds to PtdIns(3)P, a lipid enriched in early endosome membranes, and to phosphatidic acid. In contrast to TRPL, rhabdomeral localization of the membrane proteins Rh1 and TRP is not affected in the ttd14 P75L mutant. The ttd14 P75L mutation results in Rh1-independent photoreceptor degeneration and larval lethality suggesting that other processes are also affected by the ttd14 P75L mutation. In conclusion, TTD14 is a novel regulator of TRPL trafficking, involved in internalization and subsequent sorting of TRPL into the recycling pathway that enables this ion channel to return to the plasma membrane. PMID:26509977

The GTP- and Phospholipid-Binding Protein TTD14 Regulates Trafficking of the TRPL Ion Channel in Drosophila Photoreceptor Cells.

Directory of Open Access Journals (Sweden)

Alexander C Cerny

2015-10-01

Full Text Available Recycling of signaling proteins is a common phenomenon in diverse signaling pathways. In photoreceptors of Drosophila, light absorption by rhodopsin triggers a phospholipase Cβ-mediated opening of the ion channels transient receptor potential (TRP and TRP-like (TRPL and generates the visual response. The signaling proteins are located in a plasma membrane compartment called rhabdomere. The major rhodopsin (Rh1 and TRP are predominantly localized in the rhabdomere in light and darkness. In contrast, TRPL translocates between the rhabdomeral plasma membrane in the dark and a storage compartment in the cell body in the light, from where it can be recycled to the plasma membrane upon subsequent dark adaptation. Here, we identified the gene mutated in trpl translocation defective 14 (ttd14, which is required for both TRPL internalization from the rhabdomere in the light and recycling of TRPL back to the rhabdomere in the dark. TTD14 is highly conserved in invertebrates and binds GTP in vitro. The ttd14 mutation alters a conserved proline residue (P75L in the GTP-binding domain and abolishes binding to GTP. This indicates that GTP binding is essential for TTD14 function. TTD14 is a cytosolic protein and binds to PtdIns(3P, a lipid enriched in early endosome membranes, and to phosphatidic acid. In contrast to TRPL, rhabdomeral localization of the membrane proteins Rh1 and TRP is not affected in the ttd14P75L mutant. The ttd14P75L mutation results in Rh1-independent photoreceptor degeneration and larval lethality suggesting that other processes are also affected by the ttd14P75L mutation. In conclusion, TTD14 is a novel regulator of TRPL trafficking, involved in internalization and subsequent sorting of TRPL into the recycling pathway that enables this ion channel to return to the plasma membrane.

Seed viability of five wild Saudi Arabian species by germination and X-ray tests.

Science.gov (United States)

Al-Hammad, B A; Al-Ammari, B S

2017-09-01

Our objective was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of five wild species ( Moringa peregrina , Abrus precatorius , Arthrocnemum macrostachyum , Acacia ehrenbergiana and Acacia tortilis ) from Saudi Arabia. Usually several days were required to determine the viability of all five species via germination tests. However, X-ray test will give immediate results on filled/viable seeds. Seeds of all species, except Acacia ehrenbergiana and Acacia tortilis showed high viability in both germination (96-72% at 25/15 °C, 94-70% at 35/25 °C) and X-ray (100-80%) test. Furthermore, there was a general agreement between the germination (19%, 14% at 25/15 °C and 17% and 12% at 35/25 °C) and X-ray (8%, 4%) tests in which seed viability of Acacia ehrenbergiana and Acacia tortilis was very low due to insect damaged embryo as shown in X-ray analysis. Seeds of Abruspreca torius have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (83% at 25/15 °C and 81% at 35/25 °C) and X-ray (96%) tests. Most of the nongerminated seeds of the five species except those of Acacia ehrenbergiana and Acacia tortilis , were alive as judged by the tetrazolium test (TZ). Thus, for the five species examined, the X-ray test was proved to be a good and rapid predictor of seed viability.

Viability costs of reproduction and behavioral compensation in western mosquitofish (Gambusia affinis).

Science.gov (United States)

Laidlaw, Clinton T; Condon, Jacob M; Belk, Mark C

2014-01-01

The cost of reproduction hypothesis suggests that current reproduction has inherent tradeoffs with future reproduction. These tradeoffs can be both in the form of energy allocated to current offspring as opposed to somatic maintenance and future reproduction (allocation costs), or as an increase in mortality as a result of morphological or physiological changes related to reproduction (viability costs). Individuals may be able to decrease viability costs by altering behavior. Female western mosquitofish, Gambusia affinis experience a reduction in swimming ability as a consequence of pregnancy. We test for a viability cost of reproduction, and for behavioral compensation in pregnant female G. affinis by measuring survival of females in early and later stages of pregnancy when exposed to predation. Late-stage pregnant females experience a 70% greater probability of mortality compared to early-stage pregnant females. The presence of a refuge roughly doubled the odds of survival of both early and late-stage pregnant females. However, there was no interaction between refuge availability and stage of pregnancy. These data do not provide evidence for behavioral compensation by female G. affinis for elevated viability costs incurred during later stages of pregnancy. Behavioral compensation may be constrained by other aspects of the cost of reproduction.

Viability costs of reproduction and behavioral compensation in western mosquitofish (Gambusia affinis.

Directory of Open Access Journals (Sweden)

Clinton T Laidlaw

Full Text Available The cost of reproduction hypothesis suggests that current reproduction has inherent tradeoffs with future reproduction. These tradeoffs can be both in the form of energy allocated to current offspring as opposed to somatic maintenance and future reproduction (allocation costs, or as an increase in mortality as a result of morphological or physiological changes related to reproduction (viability costs. Individuals may be able to decrease viability costs by altering behavior. Female western mosquitofish, Gambusia affinis experience a reduction in swimming ability as a consequence of pregnancy. We test for a viability cost of reproduction, and for behavioral compensation in pregnant female G. affinis by measuring survival of females in early and later stages of pregnancy when exposed to predation. Late-stage pregnant females experience a 70% greater probability of mortality compared to early-stage pregnant females. The presence of a refuge roughly doubled the odds of survival of both early and late-stage pregnant females. However, there was no interaction between refuge availability and stage of pregnancy. These data do not provide evidence for behavioral compensation by female G. affinis for elevated viability costs incurred during later stages of pregnancy. Behavioral compensation may be constrained by other aspects of the cost of reproduction.

Economic viability of new launched school lunch programmes

DEFF Research Database (Denmark)

Jensen, Jørgen Dejgård; Smed, Sinne; Mørkbak, Morten Raun

2013-01-01

activities related to the schools’ support and the users’ feeling of ownership, as well as internal professionalism and leadership in the implementation of the school lunch programme are important for the viability of the programme. Strong performance on the latter factors might to some extent compensate...

Influence of gamma irradiation on pollen viability, germination ability ...

African Journals Online (AJOL)

STORAGESEVER

2009-12-15

Dec 15, 2009 ... minor cross-incompatibilities and physiological studies of incompatibility ... campanula shape of the flowers attractive for insect. (bees are ..... irradiation of cacao (Theobroma cacao L.) pollen: Effect on pollen grain viability ...

Effects of ultraviolet radiation on viability of isolated Beta vulgaris and Hordeum vulgare protoplasts

International Nuclear Information System (INIS)

Bornman, J.F.; Bjoern, L.O.; Bornman, C.H.

1982-01-01

Estimates of viability as measured by vital straining with fluorescein diacetate were carried out on freshly isolated and partially aged (16-hour-old) Beta vulgaris and Hordeum vulgare mesophyll protoplasts following irradiation with UV-B. Damage to the photosynthetic system by UV-B was determined by delayed light emission (DLE). In the case of freshly isolated Protoplasts Beta was approximately 30% more susceptible than Hordeum following 3h irradiation, with viability decreasing from 90% to 40%. After storage of protoplasts on ice for 16 h UV-B radiation markedly depressed viability in both species, but in the case of Hordeum there was a substantial initial loss of nearly 70% in viability over the first hour of irradiation. The first 10 min of UV-B radiation decreased the intensity of DLE by 40% without appreciably affecting the decay rate. Longer treatment times did not give a proportional effect so that even after 60 min of UV-B the inhibition did not exceed 60%. This suggested that although the enzyme system responsible for FDA hydrolysis may be partially inactivated (viability was 75-80% as compared with 90% in the control), the UV-B did not penetrate the innermost parts of the chloroplasts, but left some thylakoids undamaged. (orig.)

Anticipating mismatches of HIT investments: Developing a viability-fit model for e-health services.

Science.gov (United States)

Mettler, Tobias

2016-01-01

Albeit massive investments in the recent years, the impact of health information technology (HIT) has been controversial and strongly disputed by both research and practice. While many studies are concerned with the development of new or the refinement of existing measurement models for assessing the impact of HIT adoption (ex post), this study presents an initial attempt to better understand the factors affecting viability and fit of HIT and thereby underscores the importance of also having instruments for managing expectations (ex ante). We extend prior research by undertaking a more granular investigation into the theoretical assumptions of viability and fit constructs. In doing so, we use a mixed-methods approach, conducting qualitative focus group discussions and a quantitative field study to improve and validate a viability-fit measurement instrument. Our findings suggest two issues for research and practice. First, the results indicate that different stakeholders perceive HIT viability and fit of the same e-health services very unequally. Second, the analysis also demonstrates that there can be a great discrepancy between the organizational viability and individual fit of a particular e-health service. The findings of this study have a number of important implications such as for health policy making, HIT portfolios, and stakeholder communication. Copyright © 2015. Published by Elsevier Ireland Ltd.

Viability and vigour of ageing winter wheat grains

Directory of Open Access Journals (Sweden)

Stanisław Grzesiuk

2014-01-01

Full Text Available The viability and vigour of ageing winter wheat caryopses of the cvs. Grana and Jana were tested. Viability was determined on the basis of germination capacity and rate, and vigour on the basis of the over-all activity of hydrogenases in the sprouts, exudate conductometry, analysis of sprout growth, oxygen uptake and mitochondrial protein content in the sprouts. What is called energy (or rate of germination and over-all dehydrogenase activity in embryos and sprouts and the electroconductivity of exudates were found to be very good measures of the vigour of ageing caryopses. The latter two indices of vigour should be determined at a strictly defined moment of swelling and germination. Good measures of caryopse vigour are also respiration during swelling and at the beginning of germination and mitochondrial protein content in the sprouts or seedlings. There is a high correlation between the vigour of ageing grain and its bioenergetic indices.

Traffic networks as information systems a viability approach

CERN Document Server

Aubin, Jean-Pierre

2017-01-01

This authored monograph covers a viability to approach to traffic management by advising to vehicles circulated on the network the velocity they should follow for satisfying global traffic conditions;. It presents an investigation of three structural innovations: The objective is to broadcast at each instant and at each position the advised celerity to vehicles, which could be read by auxiliary speedometers or used by cruise control devices. Namely, 1. Construct regulation feedback providing at each time and position advised velocities (celerities) for minimizing congestion or other requirements. 2. Taking into account traffic constraints of different type, the first one being to remain on the roads, to stop at junctions, etc. 3. Use information provided by the probe vehicles equipped with GPS to the traffic regulator; 4. Use other global traffic measures of vehicles provided by different types of sensors; These results are based on convex analysis, intertemporal optimization and viability theory as mathemati...

Cost viability of 3D printed house in UK

Science.gov (United States)

Tobi, A. L. Mohd; Omar, S. A.; Yehia, Z.; Al-Ojaili, S.; Hashim, A.; Orhan, O.

2018-03-01

UK has been facing housing crisis due to the rising price of the property on sale. This paper will look into the viability of 3D printing technology as an alternative way for house construction on UK. The analysis will be carried out based on the data until the year of 2014 due to limited resources availability. Details cost breakdown on average size house construction cost in UK were analysed and relate to the cost viability of 3D printing technology in reducing the house price in UK. It is found that the 3D printing generates saving of up to around 35% out of total house price in UK. This cost saving comes from the 3D printed construction of walls and foundations for material and labour cost.

Photoreceptor PhyB Involved in Arabidopsis Temperature Perception and Heat-Tolerance Formation.

Science.gov (United States)

Song, Junyi; Liu, Qijun; Hu, Biru; Wu, Wenjian

2017-06-05

The influence of temperature on plants is essential. However, our knowledge on the intricate regulation process underlying heat stress (HS) response in plants is limited. Recently, information about thermal sensors in vivo has begun to emerge. In this study, another primary environmental stimulus, light, was verified once again to work with temperature synergistically on plants, through the modulation of numerous biological processes. With the application of transcriptomic analysis, a substantial number of heat-responsive genes were detected involved in both light- and phytohormone-mediated pathways in Arabidopsis. During this process, phytoreceptor phyB acts as a molecular switch to turn on or turn off several other genes HS response, under different light conditions. Furthermore, a morphological study showed the afunction of phyB enhanced plants thermal tolerance, confirming the important role of this phytochrome in temperature perception and response in plants. This study adds data to the picture of light and temperature signaling cross-talk in plants, which is important for the exploration of complicated HS responses or light-mediated mechanisms. Furthermore, based on its influence on Arabidopsis thermal response in both morphological and physiological levels, phyB is a photoreceptor, as revealed before, as well as an essential thermal sensor in plants.

Solar lanterns for domestic lighting in India. Viability of central charging station model

International Nuclear Information System (INIS)

Chaurey, A.; Kandpal, T.C.

2009-01-01

About 68 million households in India rely on kerosene as a fuel for domestic lighting. Kerosene-based lighting devices, not only for poor quality of light, but also for the risks of indoor air pollution and fire hazards, etc. are not a desired option for domestic lighting purposes. Solar lantern is a better alternative in terms of its quality of illumination, durability and versatility of use. The dissemination model for solar lantern in India has so far been based on cash sales with or without the incentive of capital subsidy. This paper analyses several dissemination models including rental and fee-for-service based on centralized solar charging station concept for CFL- and LED-based designs of solar lanterns available in India. The basis of comparison is the acceptable daily costs or rental to the user as well as to the owner of the charging station. Further, the paper studies the impact of likely escalation in kerosene price on the acceptable daily rental and estimates the amount of subsidy required to make the charging station model viable for disseminating solar lanterns among rural households. (author)

Location of macular xanthophylls in the most vulnerable regions of photoreceptor outer-segment membranes.

Science.gov (United States)

Subczynski, Witold K; Wisniewska, Anna; Widomska, Justyna

2010-12-01

Lutein and zeaxanthin are two dietary carotenoids that compose the macular pigment of the primate retina. Another carotenoid, meso-zeaxanthin, is formed from lutein in the retina. A membrane location is one possible site where these dipolar, terminally dihydroxylated carotenoids, named macular xanthophylls, are accumulated in the nerve fibers and photoreceptor outer segments. Macular xanthophylls are oriented perpendicular to the membrane surface, which ensures their high solubility, stability, and significant effects on membrane properties. It was recently shown that they are selectively accumulated in membrane domains that contain unsaturated phospholipids, and thus are located in the most vulnerable regions of the membrane. This location is ideal if they are to act as lipid antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect the retina from age-related macular degeneration. In this mini-review, we examine published data on carotenoid-membrane interactions and present our hypothesis that the specific orientation and location of macular xanthophylls maximize their protective action in membranes of the eye retina. Copyright © 2010 Elsevier Inc. All rights reserved.

Biochemical Characteristics and Viability of Probiotic and Yogurt Bacteria in Yogurt during the Fermentation and Refrigerated Storage

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F Sarvari

2014-09-01

Full Text Available This research aimed to investigate the viability of probiotic bacteria (Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12 and yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in yogurt during the fermentation, immediately after fermentation and during refrigerated storage (21 d, 4˚C. Also the biochemical characteristics of milk as affected by the commercial 4-strain mixed starter culture were investigated. Storage time affected the viability of all bacterial species. The concentration of lactic acid during the fermentation increased in parallel with the titrable acidity, and the concentration of acetic acid was proportional to the viability of Bifidobacterium lactis. The acetaldehyde level was decreased in the yogurt from day 0 up to the end of the storage. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were multiplied considerably during the fermentation. Streptococcus thermophilus could maintain its viability to the highest level, but Lactobacillus delbrueckii ssp. bulgaricus lost its viability rapidly during the cold storage compared to Streptococcus thermophilus. The multiplication and viability of probiotic bacteria were also influenced by the associative strains and species of yogurt organisms. Bifidobacteria counts were satisfactory. The loss of viability for bifidobacteria was gradual and steady during the storage, and they showed good stability during the storage as compared to Lactobacillus acidophilus.

Viability of bull semen extended with commercial semen extender ...

African Journals Online (AJOL)

Andrea Raseona

stored at 24 °C. Sperm motility parameters, morphology, and viability were analysed ... body size, slow average daily weight gain, decreased fertility, extended .... were determined by counting a total of 200 spermatozoa per each stained slide.

Effect of Isolation Techniques on Viability of Bovine Blood Neutrophils

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P. Sláma

2006-01-01

Full Text Available The effect of selected isolation methods on the viability of neutrophil granulocytes (neutrophils from the blood of healthy Holstein x Bohemian Red Pied crossbred heifers was evaluated. Two methods of neutrophil isolation were used: a neutrophil isolation on the basis of hypotonic erythrocyte lysis (in two variants: after the erythrocyte lysis proper, the cells were centrifuged at either 200 g or 1000 g, and b neutrophil isolation with FACS Lysing Solution as the lysing agent. The viability of the isolated neutrophils was evaluated on the basis of apoptosis and necrosis. The results obtained with flow cytometry (FCM suggest that, from the isolation techniques used, the method based on FACS Lysing Solution impaired the neutrophil viability least. After the application of this method, 5.36 ± 2.15% of neutrophils were apoptotic and 0.51 ± 0.12% were necrotic. In contrast, when the hypotonic erythrocyte lysis was used, the proportion of apoptotic neutrophils amounted to 42.14 ± 7.12% and 49.00 ± 14.70%, respectively, and 41.12 ± 5.55% and 36.91 ± 24.38% respectively of necrotic neutrophils (P < 0.01. This was also confirmed by the light microscopy. After the isolation with FASC Lysing Solution, 1.92 ± 1.74% of neutrophils were apoptotic and 1.05 ± 0.76% were necrotic, as distinct from after the hypotonic erythrocyte lysis where 9.43 ± 3.69% of neutrophils were apoptotic and 12.67 ± 4.74% of necrotic after centrifugation at 200 g, while 12.60 ± 4.35 were apoptotic and 14.96 ± 12.64% were necrotic after centrifugation at 1000 g. It follows from the above-mentioned data that hypotonic lysis is not a suitable method for the isolation of neutrophils, as the method itself markedly affects cell viability.

Influence of boundary-layer dynamics on pollen dispersion and viability

Science.gov (United States)

Arritt, Raymond W.; Viner, Brian J.; Westgate, Mark E.

2013-04-01

Adoption of genetically modified (GM) crops has raised concerns that GM traits can accidentally cross into conventional crops or wild relatives through the transport of wind-borne pollen. In order to evaluate this risk it is necessary to account both for dispersion of the pollen grains and environmental influences on pollen viability. The Lagrangian approach is suited to this problem because it allows tracking the environmental temperature and moisture that pollen grains experience as they travel. Taking advantage of this capability we have combined a high-resolution version of the WRF meteorological model with a Lagrangian particle dispersion model to predict maize pollen dispersion and viability. WRF is used to obtain fields of wind, turbulence kinetic energy, temperature, and humidity which are then used as input to the Lagrangian dispersion model. The dispersion model in turn predicts transport of a statistical sample of a pollen cloud from source plants to receptors. We also use the three-dimensional temperature and moisture fields from WRF to diagnose changes in moisture content of the pollen grains and consequent loss of viability. Results show that turbulent motions in the convective boundary layer counteract the large terminal velocity of maize pollen grains and lift them to heights of several hundred meters, so that they can be transported long distances before settling to the ground. We also found that pollen lifted into the upper part of the boundary layer remains more viable than has been inferred using surface observations of temperature and humidity. This is attributed to the thermal and moisture structure that typifies the daytime atmospheric boundary layer, producing an environment of low vapor pressure deficit in the upper boundary layer which helps maintain pollen viability.

Cone photoreceptor structure in patients with x-linked cone dysfunction and red-green color vision deficiency

DEFF Research Database (Denmark)

Patterson, Emily J.; Wilk, Melissa; Langlo, Christopher S.

2016-01-01

encoded by exon 4, and two with a novel insertion in exon 2. Foveal cone structure and retinal thickness was disrupted to a variable degree, even among related individuals with the same L/M array. CONCLUSIONS. Our findings provide a direct link between disruption of the cone mosaic and L/ M opsin variants......PURPOSE. Mutations in the coding sequence of the L and M opsin genes are often associated with X-linked cone dysfunction (such as Bornholm Eye Disease, BED), though the exact color vision phenotype associated with these disorders is variable. We examined individuals with L/ M opsin gene mutations...... to clarify the link between color vision deficiency and cone dysfunction.  METHODS. We recruited 17 males for imaging. The thickness and integrity of the photoreceptor layers were evaluated using spectral-domain optical coherence tomography. Cone density was measured using high-resolution images of the cone...

Determination of Complement-Mediated Killing of Bacteria by Viability Staining and Bioluminescence

OpenAIRE

Virta, Marko; Lineri, Sanna; Kankaanpää, Pasi; Karp, Matti; Peltonen, Karita; Nuutila, Jari; Lilius, Esa-Matti

1998-01-01

Complement-mediated killing of bacteria was monitored by flow cytometric, luminometric, and conventional plate counting methods. A flow cytometric determination of bacterial viability was carried out by using dual staining with a LIVE/DEAD BacLight bacterial viability kit. In addition to the viable cell population, several other populations emerged in the fluorescence histogram, and there was a dramatic decrease in the total cell count in the light-scattering histogram in the course of the co...

Seed viability of five wild Saudi Arabian species by germination and X-ray tests

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B.A. Al-Hammad

2017-09-01

Full Text Available Our objective was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of five wild species (Moringa peregrina, Abrus precatorius, Arthrocnemum macrostachyum, Acacia ehrenbergiana and Acacia tortilis from Saudi Arabia. Usually several days were required to determine the viability of all five species via germination tests. However, X-ray test will give immediate results on filled/viable seeds. Seeds of all species, except Acacia ehrenbergiana and Acacia tortilis showed high viability in both germination (96–72% at 25/15 °C, 94–70% at 35/25 °C and X-ray (100–80% test. Furthermore, there was a general agreement between the germination (19%, 14% at 25/15 °C and 17% and 12% at 35/25 °C and X-ray (8%, 4% tests in which seed viability of Acacia ehrenbergiana and Acacia tortilis was very low due to insect damaged embryo as shown in X-ray analysis. Seeds of Abruspreca torius have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min, and they exhibited high viability in both the germination (83% at 25/15 °C and 81% at 35/25 °C and X-ray (96% tests. Most of the nongerminated seeds of the five species except those of Acacia ehrenbergiana and Acacia tortilis, were alive as judged by the tetrazolium test (TZ. Thus, for the five species examined, the X-ray test was proved to be a good and rapid predictor of seed viability.

The relationship between myocardial blood flow and myocardial viability after reperfusion. Myocardial viability assessed by [sup 15]O-water-PET

Energy Technology Data Exchange (ETDEWEB)

Tsukagoshi, Joichi (Gunma Univ., Maebashi (Japan). School of Medicine)

1994-09-01

The purpose of this study was to examine the relationship between myocardial blood flow and myocardial viability in the ischemic canine myocardium after reperfusion. Transient ischemia was induced by 60-, 90-, and 180-minute occlusion of the left anterior descending coronary artery. Myocardial blood flow (MBF) was measured in the areas in which regional contractility was severely impaired (ehocardiographically akinetic or dyskinetic) in the early reperfusion period by [sup 15]O-water positron emission tomography (PET) 12 hours and 4 weeks after reperfusion. An MBF ratio of ischemic to nonischemic regions 12 hours after reperfusion was inversely correlated with the amount of histologically determined tissue necrosis (r=-0.74). The regional contractility recovered 4 weeks later in the areas where an MBF ratio was 0.48 or greater, but did not recover in the areas with a lower MBF ratio. Thus, myocardial viability can be appropriately predicted in the early phase of myocardial perfusion by PET with [sup 15]O-water even in the absence of metabolic imaging. (author).

Morphological observation and analysis using automated image cytometry for the comparison of trypan blue and fluorescence-based viability detection method.

Science.gov (United States)

Chan, Leo Li-Ying; Kuksin, Dmitry; Laverty, Daniel J; Saldi, Stephanie; Qiu, Jean

2015-05-01

The ability to accurately determine cell viability is essential to performing a well-controlled biological experiment. Typical experiments range from standard cell culturing to advanced cell-based assays that may require cell viability measurement for downstream experiments. The traditional cell viability measurement method has been the trypan blue (TB) exclusion assay. However, since the introduction of fluorescence-based dyes for cell viability measurement using flow or image-based cytometry systems, there have been numerous publications comparing the two detection methods. Although previous studies have shown discrepancies between TB exclusion and fluorescence-based viability measurements, image-based morphological analysis was not performed in order to examine the viability discrepancies. In this work, we compared TB exclusion and fluorescence-based viability detection methods using image cytometry to observe morphological changes due to the effect of TB on dead cells. Imaging results showed that as the viability of a naturally-dying Jurkat cell sample decreased below 70 %, many TB-stained cells began to exhibit non-uniform morphological characteristics. Dead cells with these characteristics may be difficult to count under light microscopy, thus generating an artificially higher viability measurement compared to fluorescence-based method. These morphological observations can potentially explain the differences in viability measurement between the two methods.

Protective function of pyridoxamine on retinal photoreceptor cells via activation of the p‑Erk1/2/Nrf2/Trx/ASK1 signalling pathway in diabetic mice.

Science.gov (United States)

Ren, Xiang; Sun, Hong; Zhang, Chenghong; Li, Chen; Wang, Jinlei; Shen, Jie; Yu, Dong; Kong, Li

2016-07-01

The present study aimed to investigate the mechanisms that mediate the protective effects of pyridoxamine (PM) on light‑damaged retinal photoreceptor cells in diabetic mice. A high‑fat diet and streptozotocin were used to induce a mouse model of type II diabetes. During the experiment, mice were divided the mice into three types of group, as follows: Control groups (negative control and light‑damaged groups); experimental groups (diabetic and diabetic light‑damaged groups); and treatment groups (25, 50 and 100 mg/kg PM‑treated groups). Using hematoxylin‑eosin staining, the number of nuclear layer cells were counted. Western blotting and immunohistochemistry were performed to measure the levels of thioredoxin (Trx), phospho‑extracellular signal‑regulated kinase 1/2 (p‑Erk1/2), nuclear factor erythroid 2‑related factor 2 (Nrf2) and apoptosis signal‑regulating kinase 1 (ASK1). The photoreceptor cell count in the outer nuclear layer of the light‑damaged, diabetic control and diabetic light‑damaged groups were significantly reduced compared with the negative control group (PTrx, p‑Erk1/2 and Nrf2 expression levels (PTrx, p‑Erk1/2 and Nrf2 expression levels were significantly increased (PTrx, p‑Erk1/2 and Nrf2 expression, and the downregulation of ASK1 expression.

Group B streptococcal beta-hemolysin/cytolysin directly impairs cardiomyocyte viability and function.

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Mary E Hensler

Full Text Available BACKGROUND: Group B Streptococcus (GBS is a leading cause of neonatal sepsis where myocardial dysfunction is an important contributor to poor outcome. Here we study the effects of the GBS pore-forming beta-hemolysin/cytolysin (Bh/c exotoxin on cardiomyocyte viability, contractility, and calcium transients. METHODOLOGY/PRINCIPAL FINDINGS: HL-1 cardiomyocytes exposed to intact wild-type (WT or isogenic Deltabeta h/c mutant GBS, or to cell-free extracts from either strain, were assessed for viability by trypan blue exclusion and for apoptosis by TUNEL staining. Functionality of exposed cardiomyocytes was analyzed by visual quantitation of the rate and extent of contractility. Mitochondrial membrane polarization was measured in TMRE-loaded cells exposed to GBS beta h/c. Effects of GBS beta h/c on calcium transients were studied in fura-2AM-loaded primary rat ventricular cardiomyocytes. Exposure of HL-1 cardiomyocytes to either WT GBS or beta h/c extracts significantly reduced both rate and extent of contractility and later induced necrotic and apoptotic cell death. No effects on cardiomyocyte viability or function were observed after treatment with Deltabeta h/c mutant bacteria or extracts. The beta h/c toxin was associated with complete and rapid loss of detectable calcium transients in primary neonatal rat ventricular cardiomyocytes and induced a loss of mitochondrial membrane polarization. These effects on viability and function were abrogated by the beta h/c inhibitor, dipalmitoyl phosphatidylcholine (DPPC. CONCLUSIONS/SIGNIFICANCE: Our data show a rapid loss of cardiomyocyte viability and function induced by GBS beta h/c, and these deleterious effects are inhibited by DPPC, a normal constituent of human pulmonary surfactant.. These findings have clinical implications for the cardiac dysfunction observed in neonatal GBS infections.

Knock-in strategy at 3'-end of Crx gene by CRISPR/Cas9 system shows the gene expression profiles during human photoreceptor differentiation.

Science.gov (United States)

Homma, Kohei; Usui, Sumiko; Kaneda, Makoto

2017-03-01

Fluorescent reporter gene knock-in induced pluripotent stem cell (iPSC) lines have been used to evaluate the efficiency of differentiation into specific cell lineages. Here, we report a knock-in strategy for the generation of human iPSC reporter lines in which a 2A peptide sequence and a red fluorescent protein (E2-Crimson) gene were inserted at the termination codon of the cone-rod homeobox (Crx) gene, a photoreceptor-specific transcriptional factor gene. The knock-in iPSC lines were differentiated into fluorescence-expressing cells in 3D retinal differentiation culture, and the fluorescent cells also expressed Crx specifically in the nucleus. We found that the fluorescence intensity was positively correlated with the expression levels of Crx mRNA and that fluorescent cells expressed rod photoreceptor-specific genes in the later stage of differentiation. Finally, we treated the fluorescent cells with DAPT, a Notch inhibitor, and found that DAPT-enhanced retinal differentiation was associated with up-regulation of Crx, Otx2 and NeuroD1, and down-regulation of Hes5 and Ngn2. These suggest that this knock-in strategy at the 3'-end of the target gene, combined with the 2A peptide linked to fluorescent proteins, offers a useful tool for labeling specific cell lineages or monitoring expression of any marker genes without affecting the function of the target gene. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Determination of intestinal viability by Doppler ultrasonography in venous infarction.

Science.gov (United States)

Cooperman, M; Martin, E W; Carey, L C

1980-01-01

The accuracy of Doppler ultrasound in predicting the viability of ischemic intestine secondary to venous obstruction was assessed. Twenty loops of ischemic intestine were created in dogs by temporarily obstructing venous return from the bowel. Doppler arterial flow signals within the intestine quickly disappeared following venous occlusion. In ten segments, arterial signals promptly returned following release of venous occlusion. Nine of these ten segments were viable at reoperation 24 hours later. In ten segments, no arterial signals could be detected following release of venous occlusion, and only one segment proved to be viable. Doppler ultrasound findings were far more accurate in distinguishing between viable and nonviable intestine thatn were clinical guides to intestinal viability. PMID:7352777

Mechanism of H₂O₂-induced oxidative stress regulating viability and biocontrol ability of Rhodotorula glutinis.

Science.gov (United States)

Chen, Jian; Li, Boqiang; Qin, Guozheng; Tian, Shiping

2015-01-16

The use of antagonistic yeasts to control postharvest pathogens is a promising alternative to fungicides. The effectiveness of the antagonists against fungal pathogens is greatly dependent on their viability, which is usually mediated by reactive oxygen species (ROS). Here, we investigated the effects of H₂O₂-induced oxidative stress on the viability and biocontrol efficacy of Rhodotorula glutinis and, using flow cytometric analysis, observed the changes of ROS accumulation and apoptosis in the yeast cells with or without H₂O₂ treatment. We found that the viability of R. glutinis decreased in a time- and dose-dependent manner under H₂O₂-induced oxidative stress. Compared to the control, yeast cells exposed to oxidative stress exhibited more accumulation of ROS and higher levels of protein oxidative damage, but showed lower efficacy for biocontrol of Penicillium expansum causing blue mold rot on peach fruit. The results indicate that apoptosis is a main cause of the cell viability loss in R. glutinis, which is attributed to ROS accumulation under oxidative stress. These findings offer a plausible explanation that oxidative stress affects biocontrol efficacy of R. glutinis via regulating its viability and cell apoptosis. Copyright © 2014 Elsevier B.V. All rights reserved.

Relevance of control theory to design and maintenance problems in time-variant reliability: The case of stochastic viability

International Nuclear Information System (INIS)

Rougé, Charles; Mathias, Jean-Denis; Deffuant, Guillaume

2014-01-01

The goal of this paper is twofold: (1) to show that time-variant reliability and a branch of control theory called stochastic viability address similar problems with different points of view, and (2) to demonstrate the relevance of concepts and methods from stochastic viability in reliability problems. On the one hand, reliability aims at evaluating the probability of failure of a system subjected to uncertainty and stochasticity. On the other hand, viability aims at maintaining a controlled dynamical system within a survival set. When the dynamical system is stochastic, this work shows that a viability problem belongs to a specific class of design and maintenance problems in time-variant reliability. Dynamic programming, which is used for solving Markovian stochastic viability problems, then yields the set of design states for which there exists a maintenance strategy which guarantees reliability with a confidence level β for a given period of time T. Besides, it leads to a straightforward computation of the date of the first outcrossing, informing on when the system is most likely to fail. We illustrate this approach with a simple example of population dynamics, including a case where load increases with time. - Highlights: • Time-variant reliability tools cannot devise complex maintenance strategies. • Stochastic viability is a control theory that computes a probability of failure. • Some design and maintenance problems are stochastic viability problems. • Used in viability, dynamic programming can find reliable maintenance actions. • Confronting reliability and control theories such as viability is promising

NPP Cernavoda unit 2 economic viability: The challenge for an advanced financing scheme

International Nuclear Information System (INIS)

Condu, M.; Popescu, D.

1999-01-01

The completion of Cernavoda Unit-2 being no doubt, the viability of the project was analyzed and strengthened. Economic justification of the decision to complete Unit-2 is described, including assessment of its safety design guides, design requirements and engineering design solutions in the light of changes in codes, guideline, standards and actual regulatory requirements. Cost-benefit analysis demonstrates the economic viability of the project

Cosmological viability conditions for f(T) dark energy models

Energy Technology Data Exchange (ETDEWEB)

Setare, M.R.; Mohammadipour, N., E-mail: rezakord@ipm.ir, E-mail: N.Mohammadipour@uok.ac.ir [Department of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2012-11-01

Recently f(T) modified teleparallel gravity where T is the torsion scalar has been proposed as the natural gravitational alternative for dark energy. We perform a detailed dynamical analysis of these models and find conditions for the cosmological viability of f(T) dark energy models as geometrical constraints on the derivatives of these models. We show that in the phase space exists two cosmologically viable trajectory which (i) The universe would start from an unstable radiation point, then pass a saddle standard matter point which is followed by accelerated expansion de sitter point. (ii) The universe starts from a saddle radiation epoch, then falls onto the stable matter era and the system can not evolve to the dark energy dominated epoch. Finally, for a number of f(T) dark energy models were proposed in the more literature, the viability conditions are investigated.

Prolonging the viability of Lactobacillus plantarum through the addition of prebiotics into the medium.

Science.gov (United States)

Altieri, Clelia; Bevilacqua, Antonio; Sinigaglia, Milena

2011-08-01

This article reports on the effects of prebiotics on the growth/death kinetics, metabolism, and biomass production by 2 strains of Lactobacillus plantarum (c19 and DSMZ 2601, isolated from table olives and purchased from a Public Collection, respectively). The research was divided into 3 different steps, in order to highlight the optimal combination for cell viability and experiments were performed under the conditions of an accelerated shelf life test; thus, 3 combinations were pointed out (fructooligosaccharides [FOS], 5 g/L; glucose + inulin, 2.5 + 2.5 g/L; glucose + FOS, 2.5 + 2.5 g/L). A sample containing only glucose was used as control. The results highlighted that the 3 combinations aforementioned prolonged cell viability over the time both under low and high inoculum conditions (3 and 9 log CFU/mL, respectively); however, FOS alone caused a reduction of biomass production, even if cell number was not affected by this compound. Therefore, as a final result of this research, the combination glucose + FOS could be proposed as a suitable mean to achieve an optimal production of biomass and prolong cell viability over the time. Food producers require a prolonged viability of probiotic bacteria in functional foods; this goal is usually achieved by refrigeration. In this article, the prolongation of cell viability through the addition of prebiotics was proposed. © 2011 Institute of Food Technologists®

The Viability of the Lactobacillus Rhamnosus IL4.2 Strain in Simulated Gastrointestinal Conditions

Directory of Open Access Journals (Sweden)

Emanuel Vamanu

2011-05-01

Full Text Available The viability maintenance of Lactobacillus rhamnosus IL4.2 strain in gastrointestinal conditions represents one of the most important characteristics regarding its use for obtaining probiotic products. The tests were performed with a cell suspension kept in 0.5% NaCl. The influence of pepsin (3 g/l at pH of 1.5, 2, 2.5 and 3, as well as of pancreatin (1 g/l in the presence of bile salts (1.5, 2, 3 and 5 mg/ml were determined. The influence of casein and mucin, in a concentration of 1 g/l, was also established in the aforementioned conditions. It was observed that mucin presented a longer viability maintenance, fact also confirmed by the calculation of the mathematical parameters of viability and mortality, when mucin was either used or not, especially in the case of gastric transit. The results proved that the tested strain maintained its viability even at pH between 1.8 - 2 and at an even higher concentration, of 2 mg/ml of bile salts, but up to two hours as of the exposure to the conditions of the simulated small intestinal juice. Such results were also confirmed by the cumulated effect of the simulated gastric and small intestinal juice, the strain thus increasing its viability with an average of 10% in the presence of mucin.

Examination of viability and quality of ovarian tissue after cryopreservation using simple laboratory methods in ewe

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Guerin Jean F

2011-06-01

Full Text Available Abstract Background The objective of the present study is to assess viability tests and to evaluate follicle ovarian tissue quality after freezing-thawing procedures. Methods Ewe's ovaries were harvested at the slaughterhouse, after dissection each ovarian specimen was divided into two groups: fresh tissue (control group and frozen tissue. In the first part of the study, the follicles viability was assessed by trypan blue staining, calcein AM/ethidium homodimer-1 staining (LIVE/DEAD viability/cytotoxicity kit, Molecular Probes and morphology in the two groups. In the second part of the study the quality of the whole ovarian tissue was evaluated by the quantification of the release of lactate dehydrogenase measurement (Cytotoxicity Detection kit ROCHE, DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL in primordial and primary follicles (ApopDETEK Kit system Enzo and morphology in the two groups. 100 Follicles (primordial and primary were counted on both fresh and frozen hemiovary to assess this various tests. Results Ovarian follicle viability assessment was similar using trypan blue or calcein/ethidium staining. Follicles showed a decreased viability after freezing-thawing. After cryopreservation, a significant correlation between the percentage of normal follicles and viability rate was found using trypan blue (r = 0.82, p Conclusion We suggest the use of trypan blue staining for the histological assessment of viability, the use of LDH assay for the cytotoxicity assessement and finally the use of DNA fragmentation assessment to valid different freezing-thawing protocols.

Effect of Storage Temperature on Beauveria bassiana (Bals. Vuill. Viability on Several Carriers

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Sri Sukamto

2006-05-01

Full Text Available One of the entomopatogenous fungus types commonly observed and showed potency as myco-insectiside is Beauveria bassiana(Bals. Vuill.In order to support effectiveness and patogenous activity of B. bassiana, it is necessary to add a carrying agent that protects its spores from ultra violet ray. This study aims to investigate the effect of storage temperature on viability of B. Bassianaspores on the carrier material. The observation was carried out in the Laboratory of Plant Diseases, Indonesian Coffee and Cocoa Research Institute. The research was arranged in completely randomized design by three factors. The first factor was carrier (C, that consists of C1 = rice flour, C2 = maize flour and C3 = tapioca flour. The second factor was dosage (D, that consists of D1 = 1 g B. bassiana+ 1 g carrier; D2 = 1 g B. bassiana+ 5 g carrier and D3 = 1 g B. bassiana+ 10 g carrier. The third factor was temperature of the storage (T,that consists of T1 = 5oC; T2 = 23oC and T3 = 29oC. Viability of B. Bassiana spores was examined by observing development of 100 blastopores randomly and determined under light microscope with 400 times magnification. Observation was conducted in two replicates after the spores of B. bassiana were kept in the storage for 2, 4, 8 and 16 weeks. The result showed that by adding 1 g tapioca flour and temperature of storage of 5oC was potentiall in keeping viability of B. bassianaspores at least for 2 months. It was due to that tapioca flour gave better effect than rice and maize flours in keeping the storage and appropriate low temperature. Viability of B. bassianaspores decreased with increasing carrier dosage, temperature and duration of the storage. Whereas, storage at 5oC was found to be a better condition in keeping viability of dry pure B. bassianaspores longer than conditions of 23o and 29oC. Key word:Beauveria bassiana, temperature, viability,carrier.

Approximate viability for nonlinear evolution inclusions with application to controllability

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Omar Benniche

2016-12-01

Full Text Available We investigate approximate viability for a graph with respect to fully nonlinear quasi-autonomous evolution inclusions. As application, an approximate null controllability result is given.

Assessing Technical and Programmatic Viability of Nuclear Waste and Material Stream Disposition Plans

International Nuclear Information System (INIS)

R. S. Hill; B. Griebenow

1999-01-01

The U.S. Department of Energy (DOE), Office of Environmental Management (EM) has responsibility for cleanup and disposition of nuclear wastes and excess materials that are a legacy of the nuclear arms race. In fulfilling this responsibility, EM applies a systems engineering approach to identify baseline disposition plans for the wastes and materials (storage, stabilization, treatment, and disposal), assess the path viability, and develop integration opportunities to improve the disposition viability or to combine, eliminate, and/or simplify activities, technologies, and facilities across the DOE Complex, evaluate the baseline and alternatives to make informed decisions, and implement and track selected opportunities. This paper focuses on processes used to assess the disposition path viability - the likelihood that current planning for disposition of nuclear waste and materials can be implemented

Assessment of myocardial viability using 123I-labeled iodophenylpentadecanoic acid at sustained low flow or after acute infarction and reperfusion.

Science.gov (United States)

Yang, J Y; Ruiz, M; Calnon, D A; Watson, D D; Beller, G A; Glover, D K

1999-05-01

123I-labeled iodophenylpentadecanoic acid (IPPA) is a synthetic fatty acid that may be useful for determination of myocardial viability. We investigated the uptake and clearance kinetics of this tracer in canine models of ischemia and infarction. In protocol 1, 185 MBq (5 mCi) 123I-IPPA were injected intravenously in 19 dogs with 50% left anterior descending artery (LAD) flow reduction. In 9 dogs, 201TI was coinjected. In protocol 2, 5 dogs underwent LAD occlusion for 3 h, and 123I-IPPA was injected 60 min after reperfusion. All dogs had flow measured by microspheres, regional systolic thickening by ultrasonic crystals and measurements of postmortem risk area and infarct size. Tracer activities were quantified by gamma well counting and by serial imaging. In protocol 1 dogs with sustained low flow (50% +/- 4%) and absence of systolic thickening (-3.2% +/- 1%), 123I-IPPA defect magnitude (LAD/left circumflex artery [LCX] count ratios) decreased from 0.65 +/- 0.02 to 0.74 +/- 0.02 at 30 min and to 0.84 +/- 0.03 at 2 h (P < 0.01), indicative of rest redistribution. Final transmural 123I-IPPA LAD/LCX activity ratio (0.99 +/- 0.05) was significantly greater than the flow ratio (0.53 +/- 0.04) at injection, confirming complete rest redistribution. The final 123I-IPPA activity ratio was significantly greater than the 201TI ratio over the 2-h period (P < 0.01). In protocol 2 dogs that underwent 3 h of total LAD occlusion and reflow (infarct size = 51% +/- 13% of risk area), viability was overestimated with 123I-IPPA, because uptake averaged 64% of normal in the central necrotic region, where flow averaged < 10% of normal. These findings suggest that serial 123I-IPPA imaging may be useful for assessing myocardial viability under conditions of sustained low flow and myocardial asynergy, such as appears to exist in patients with chronic coronary artery disease and depressed left ventricular function. In contrast, 123I-IPPA given early after reperfusion following prolonged

Myocardial Viability on Cardiac Magnetic Resonance.

Science.gov (United States)

Souto, Ana Luiza Mansur; Souto, Rafael Mansur; Teixeira, Isabella Cristina Resende; Nacif, Marcelo Souto

2017-05-01

The study of myocardial viability is of great importance in the orientation and management of patients requiring myocardial revascularization or angioplasty. The technique of delayed enhancement (DE) is accurate and has transformed the study of viability into an easy test, not only for the detection of fibrosis but also as a binary test detecting what is viable or not. On DE, fibrosis equal to or greater than 50% of the segmental area is considered as non-viable, whereas that below 50% is considered viable. During the same evaluation, cardiac magnetic resonance (CMR) may also use other techniques for functional and perfusion studies to obtain a global evaluation of ischemic heart disease. This study aims to highlight the current concepts and broadly emphasize the use of CMR as a method that over the last 20 years has become a reference in the detection of infarction and assessment of myocardial viability. Resumo O estudo de viabilidade miocárdica é de grande importância para a orientação e manejo de pacientes que necessitam de cirurgia de revascularização miocárdica ou angioplastia. A técnica de realce tardio (RT) é precisa e transformou o estudo de viabilidade em um teste fácil, não só para a detecção de fibrose, mas também como um modelo binário para a detecção do que é ou não é viável. Uma fibrose identificada pelo RT é considerada como não viável quando igual ou maior do que 50% da área segmentar e como viável quando menor que 50%. A ressonância magnética cardíaca (RMC) também pode lançar mão de outras técnicas para estudo funcional e de perfusão para uma avaliação global da doença isquêmica do coração no mesmo exame. Este estudo tem como objetivo destacar os conceitos atuais e enfatizar amplamente o uso da RMC como um método que nos últimos 20 anos se tornou referência na detecção de infarto e avaliação de viabilidade miocárdica.

75 FR 42474 - The Future of Aviation Advisory Committee (FAAC) Subcommittee on Competitiveness and Viability...

Science.gov (United States)

2010-07-21

... of Aviation Advisory Committee (FAAC) Subcommittee on Competitiveness and Viability; Notice of... Transportation, announces the second meeting of the FAAC Subcommittee on Competitiveness and Viability, which... recommendations to the Secretary of Transportation to ensure the competitiveness of the U.S. aviation industry and...

Extracellular matrix components expression in human pluripotent stem cell-derived retinal organoids recapitulates retinogenesis in vivo and reveals an important role for IMPG1 and CD44 in the development of photoreceptors and interphotoreceptor matrix.

Science.gov (United States)

Felemban, Majed; Dorgau, Birthe; Hunt, Nicola Claire; Hallam, Dean; Zerti, Darin; Bauer, Roman; Ding, Yuchun; Collin, Joseph; Steel, David; Krasnogor, Natalio; Al-Aama, Jumana; Lindsay, Susan; Mellough, Carla; Lako, Majlinda

2018-05-17

The extracellular matrix (ECM) plays an important role in numerous processes including cellular proliferation, differentiation, migration, maturation, adhesion guidance and axonal growth. To date, there has been no detailed analysis of the ECM distribution during retinal ontogenesis in humans and the functional importance of many ECM components is poorly understood. In this study, the expression of key ECM components in adult mouse and monkey retina, developing and adult human retina and retinal organoids derived from human pluripotent stem cells was studied. Our data indicate that basement membrane ECMs (Fibronectin and Collagen IV) were expressed in Bruch's membrane and the inner limiting membrane of the developing human retina, whilst the hyalectins (Versican and Brevican), cluster of differentiation 44 (CD44), photoreceptor-specific ECMs Interphotoreceptor Matrix Proteoglycan 1 (IMPG1) and Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) were detected in the developing interphotoreceptor matrix (IPM). The expression of IMPG1, Versican and Brevican in the developing IPM was conserved between human developing retina and human pluripotent stem cell-derived retinal organoids. Blocking the action of CD44 and IMPG1 in pluripotent stem cell derived retinal organoids affected the development of photoreceptors, their inner/outer segments and connecting cilia and disrupted IPM formation, with IMPG1 having an earlier and more significant impact. Together, our data suggest an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation during human retinogenesis. The expression and the role of many extracellular matrix (ECM) components during human retinal development is not fully understood. In this study, expression of key ECM components (Collagen IV, Fibronectin, Brevican, Versican, IMPG1 and IMPG2) was investigated during human retinal ontogenesis. Collagen IV and Fibronectin were expressed in Bruch's membrane; whereas Brevican, Versican

Effect of chlorinated ethene conversion on viability and activity of Methylosinus trichosporium OB3b

NARCIS (Netherlands)

van Hylckama Vlieg, Johan E.T.; Koning, Wim de; Janssen, Dick B.

1997-01-01

The effect of transformation of chlorinated ethenes on the cell viability of Methylosinus trichosporium OB3b was investigated. A comparison of the loss of viability with the decrease in transformation rates shelved that for the monooxygenase-mediated transformation of all chlorinated ethenes except

Loss of cellular viability in areas of ground-glass opacity on computed tomography images immediately after pulmonary radiofrequency ablation in rabbits

International Nuclear Information System (INIS)

Kuroki, Masaomi; Nakada, Hiroshi; Yamashita, Atsushi; Sawaguchi, Akira; Uchino, Noriko; Sato, Shinya; Asada, Yujiro; Tamura, Shozo; Asanuma, Taketoshi

2012-01-01

The purpose of this study was to determine cellular viability of lung parenchyma and neoplastic cells in areas of ground-glass opacity (GGO) on computed tomography (CT) images immediately after pulmonary radiofrequency ablation (RFA) in rabbits. A LeVeen RFA electrode was placed percutaneously into rabbit lungs with or without metastatic VX2 tumors. Five minutes later, seven isolated lungs were imaged by use of a multi-detector row CT scanner, and the images were compared with histological features. The cellular viability of the lung tissues was assessed by nicotinamide adenine dinucleotide hydrogen (NADH) staining in eight normal lungs and in three lungs with multiple metastatic tumors. All lung lesions appeared as bilayered structures with a central, dense, attenuated area and an outer area of GGO on CT images, and as three-layered structures on macroscopic and microscopic images 5 min after RFA. The GGO areas approximately corresponded to the outer two layers in macroscopic images that were exudative and congestive on microscopic images. Staining for NADH was significantly reduced in the GGO and densely attenuated areas with or without tumor tissue staining compared with the non-ablated area. Our results suggest that an area of GGO that appears on CT immediately after RFA can be effectively treated by RFA. (author)

Towards an understanding of the influence of national culture on organisational viability: An exploratory study

Directory of Open Access Journals (Sweden)

Awuzie Bankole O.

2017-06-01

Full Text Available ABSTRACT Viability connotes a system’s ability to become ultra-stable through effective self-regulation of its internal processes and information processing among its subsystems. Applying this to an infrastructure delivery system (IDS context, this study proposes that an IDS can successfully deliver on client requirements only if they attain and maintain viability. Research into the influence of National Culture (NC on an IDS’s viability appears to be lacking; hence this study. Adopting a multi-case study, qualitative research design, this study explores three IDSs involved in the delivery of infrastructure projects in two different NC contexts; Nigeria and the United Kingdom. 25 semi-structured interviews were conducted across the cases to provide for an in-depth understanding of existing interactions between participants in these delivery systems: client/project sponsor; main contractor and sub-contractors and to understand the influence of the prevailing national culture on such interactions, if any. Findings indicate that NC in project delivery environments influence the ability of IDSs to attain viability, especially as it pertains to the sustenance of Team Quality Attributes (TWQ within the system. Based on these findings, it is expected that in modelling IDSs for viability, adequate consideration should be given to the prevailing NC by project managers and planners.

Yeast viability and concentration analysis using lens-free computational microscopy and machine learning

Science.gov (United States)

Feizi, Alborz; Zhang, Yibo; Greenbaum, Alon; Guziak, Alex; Luong, Michelle; Chan, Raymond Yan Lok; Berg, Brandon; Ozkan, Haydar; Luo, Wei; Wu, Michael; Wu, Yichen; Ozcan, Aydogan

2017-03-01

Research laboratories and the industry rely on yeast viability and concentration measurements to adjust fermentation parameters such as pH, temperature, and pressure. Beer-brewing processes as well as biofuel production can especially utilize a cost-effective and portable way of obtaining data on cell viability and concentration. However, current methods of analysis are relatively costly and tedious. Here, we demonstrate a rapid, portable, and cost-effective platform for imaging and measuring viability and concentration of yeast cells. Our platform features a lens-free microscope that weighs 70 g and has dimensions of 12 × 4 × 4 cm. A partially-coherent illumination source (a light-emitting-diode), a band-pass optical filter, and a multimode optical fiber are used to illuminate the sample. The yeast sample is directly placed on a complementary metal-oxide semiconductor (CMOS) image sensor chip, which captures an in-line hologram of the sample over a large field-of-view of >20 mm2. The hologram is transferred to a touch-screen interface, where a trained Support Vector Machine model classifies yeast cells stained with methylene blue as live or dead and measures cell viability as well as concentration. We tested the accuracy of our platform against manual counting of live and dead cells using fluorescent exclusion staining and a bench-top fluorescence microscope. Our regression analysis showed no significant difference between the two methods within a concentration range of 1.4 × 105 to 1.4 × 106 cells/mL. This compact and cost-effective yeast analysis platform will enable automatic quantification of yeast viability and concentration in field settings and resource-limited environments.

Aptamer-based viability impedimetric sensor for bacteria.

Science.gov (United States)

Labib, Mahmoud; Zamay, Anna S; Kolovskaya, Olga S; Reshetneva, Irina T; Zamay, Galina S; Kibbee, Richard J; Sattar, Syed A; Zamay, Tatiana N; Berezovski, Maxim V

2012-11-06

The development of an aptamer-based viability impedimetric sensor for bacteria (AptaVISens-B) is presented. Highly specific DNA aptamers to live Salmonella typhimurium were selected via the cell-systematic evolution of ligands by exponential enrichment (SELEX) technique. Twelve rounds of selection were performed; each comprises a positive selection step against viable S. typhimurium and a negative selection step against heat killed S. typhimurium and a mixture of related pathogens, including Salmonella enteritidis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Citrobacter freundii to ensure the species specificity of the selected aptamers. The DNA sequence showing the highest binding affinity to the bacteria was further integrated into an impedimetric sensor via self-assembly onto a gold nanoparticle-modified screen-printed carbon electrode (GNP-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect S. typhimurium down to 600 CFU mL(-1) (equivalent to 18 live cells in 30 μL of assay volume) and distinguish it from other Salmonella species, including S. enteritidis and S. choleraesuis. This report is envisaged to open a new venue for the aptamer-based viability sensing of a variety of microorganisms, particularly viable but nonculturable (VBNC) bacteria, using a rapid, economic, and label-free electrochemical platform.

Comparison of methods used for assessing the viability and vitality of yeast cells.

Science.gov (United States)

Kwolek-Mirek, Magdalena; Zadrag-Tecza, Renata

2014-11-01

Determination of cell viability is the most commonly used method for assessing the impact of various types of stressors in toxicity research and in industrial microbiology studies. Viability is defined as a percentage of live cells in a whole population. Although cell death is one of the consequences of toxicity, chemical or physical factors may exert their toxic effects through a number of cellular alterations that may compromise cell ability to divide without necessarily leading to cell death. This aspect represents the term 'cell vitality' defined as physiological capabilities of cells. It is important to note that cell viability and cell vitality represent two different aspects of cell functions, and both are required for the estimation of the physiological state of a cell after exposure to various types of stressors and chemical or physical factors. In this paper, we introduced a classification of available methods for estimating both viability and vitality in Saccharomyces cerevisiae yeast cells (wild-type and Δsod1 mutant) in which the effects of selected oxidants causing oxidative stress is evaluated. We present the advantages as well as disadvantages of the selected methods and assess their usefulness in different types of research. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

In Vitro Pollen Viability and Pollen Germination in Cherry Laurel (Prunus laurocerasus L.

Directory of Open Access Journals (Sweden)

Melekber Sulusoglu

2014-01-01

Full Text Available Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.. Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride and IKI (iodine potassium iodide, were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r2 = 0.0614 and r2 = 0.0015, resp.. Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

In vitro pollen viability and pollen germination in cherry laurel (Prunus laurocerasus L.).

Science.gov (United States)

Sulusoglu, Melekber; Cavusoglu, Aysun

2014-01-01

Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.). Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride) and IKI (iodine potassium iodide), were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r(2) = 0.0614 and r(2) = 0.0015, resp.). Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

Viability of Event Management Business in Batangas City, Philippine: Basis for Business Operation Initiatives

Directory of Open Access Journals (Sweden)

Jeninah Christia D. Borbon

2016-11-01

Full Text Available The research study on Viability of Event Management Business in Batangas City: Basis for Business Operation Initiatives aimed to assess the viability of this type of business using Thompson’s (2005 Dimension of Business Viability as its tool in order to create business operation initiatives. It provided a good framework for defining success factors in entrepreneurial operation initiatives in a specific business type – event management. This study utilized event organizers based in Batangas, a southern popular province, which also is a great popular destination for many types of events. Findings showed that the event management business in Batangas City is generally a personal event type of business whose year of operation ranges from one to three years, mostly link to church or reception venues and usually offers on the day coordination. In the assessment of its perceived viability, it was found out that this type of business is moderately viable in terms of market, technical, business model, management model, economic and financial, and exit strategy. Among all the dimensions tested, only market, management model, economic and financial, and exit strategy showed significant relationship with the profile variables of the event management business. From the enumerated problems encountered, those that got the highest rate were demanding clients, overbooking of reservation/exceeding number of guests and failure to meet spectators and/or competitors expectations. And, the recommended business operation initiatives were based on the weaknesses discovered using Thompson’s Dimension of Business Viability Model.

Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds.

Science.gov (United States)

Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

2016-07-12

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.

Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.

Science.gov (United States)

Seeliger, Mathias W; Brombas, Arne; Weiler, Reto; Humphries, Peter; Knop, Gabriel; Tanimoto, Naoyuki; Müller, Frank

2011-11-08

Retinal photoreceptors permit visual perception over a wide range of lighting conditions. Rods work best in dim, and cones in bright environments, with considerable functional overlap at intermediate (mesopic) light levels. At many sites in the outer and inner retina where rod and cone signals interact, gap junctions, particularly those containing Connexin36, have been identified. However, little is known about the dynamic processes associated with the convergence of rod and cone system signals into ON- and OFF-pathways. Here we show that proper cone vision under mesopic conditions requires rapid adaptational feedback modulation of rod output via hyperpolarization-activated and cyclic nucleotide-gated channels 1. When these channels are absent, sustained rod responses following bright light exposure saturate the retinal network, resulting in a loss of downstream cone signalling. By specific genetic and pharmacological ablation of key signal processing components, regular cone signalling can be restored, thereby identifying the sites involved in functional rod-cone interactions.

Sustainable model for financial viability of decentralized biomass gasifier based power projects

International Nuclear Information System (INIS)

Palit, Debajit; Malhotra, Ramit; Kumar, Atul

2011-01-01

This paper made a modest attempt for designing a sustainable model for financial viability of biomass gasifier power projects for enhancing electricity access in India and other developing countries. For long term sustainability of distributed generation projects in remote rural areas, viability from both project implementing agency (PIA) and the end-users need to be ensured. The minimum required prices of electricity from both PIA and end-user perspective have been estimated. While for PIA the cost recovery is the key for viability, the affordability to pay the electricity cost is crucial for the end users. Analysis carried out in this paper on the basis of data obtained from operational projects implemented in India reveal that it is essential to operate the system at a higher capacity utilization factor. While this can be achieved though creating convergence with locally relevant economic activity, it is also observed that micro-enterprises cannot pay beyond a certain price of electricity to keep it sustainable. This paper sets forth a case for developing a regulatory mechanism to extend the tariff fixation for the projects and providing cross-subsidies to ensure long term sustainability of off-grid project. - Highlights: → We design sustainable financial model for viability of biomass gasifier projects. → Analysis based on field data obtained from operational projects in India. Estimated electricity pricing from both implementing agency and end-users perspective. → A regulatory mechanism for tariff fixation and cross subsidization is recommended.

Pollen diversity, viability and floral structure of some Musa genotypes

African Journals Online (AJOL)

Prof. Ogunji

Pollen diversity, viability and floral structure of some Musa genotypes ... at the Faculty of Agriculture & Natural Resources Management farm, Ebonyi State University,. Abakaliki. ..... Roots, tuber, plantains and bananas in human nutrition. Rome,.

UV-sensitive photoreceptor protein OPN5 in humans and mice.

Science.gov (United States)

Kojima, Daisuke; Mori, Suguru; Torii, Masaki; Wada, Akimori; Morishita, Rika; Fukada, Yoshitaka

2011-01-01

A variety of animal species utilize the ultraviolet (UV) component of sunlight as their environmental cues, whereas physiological roles of UV photoreception in mammals, especially in human beings, remain open questions. Here we report that mouse neuropsin (OPN5) encoded by the Opn5 gene exhibited an absorption maximum (λmax) at 380 nm when reconstituted with 11-cis-retinal. Upon UV-light illumination, OPN5 was converted to a blue-absorbing photoproduct (λmax 470 nm), which was stable in the dark and reverted to the UV-absorbing state by the subsequent orange light illumination, indicating its bistable nature. Human OPN5 also had an absorption maximum at 380 nm with spectral properties similar to mouse OPN5, revealing that OPN5 is the first and hitherto unknown human opsin with peak sensitivity in the UV region. OPN5 was capable of activating heterotrimeric G protein Gi in a UV-dependent manner. Immuno-blotting analyses of mouse tissue extracts identified the retina, the brain and, unexpectedly, the outer ears as the major sites of OPN5 expression. In the tissue sections of mice, OPN5 immuno-reactivities were detected in a subset of non-rod/non-cone retinal neurons as well as in the epidermal and muscle cells of the outer ears. Most of these OPN5-immuno-reactivities in mice were co-localized with positive signals for the alpha-subunit of Gi. These results demonstrate the first example of UV photoreceptor in human beings and strongly suggest that OPN5 triggers a UV-sensitive Gi-mediated signaling pathway in the mammalian tissues.

Puget Sound steelhead life cycle model analyses - Population Viability Analysis

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This research was initiated by the Puget Sound Steelhead Technical Recovery Team to develop viability criteria for threatened Puget Sound steelhead and to support...

In vivo visualization of photoreceptor layer and lipofuscin accumulation in Stargardt’s disease and fundus flavimaculatus by high resolution spectral-domain optical coherence tomography

Directory of Open Access Journals (Sweden)

Giuseppe Querques

2009-12-01

Full Text Available Giuseppe Querques, Rosy Prato, Gabriel Coscas, Gisèle Soubrane, Eric H SouiedDepartment of Ophthalmology, Hopital Intercommunal de Creteil, University Paris XII, FranceIntroduction: To assess photoreceptor (PR layer morphology in patients with Stargardt’s disease (STGD and fundus flavimaculatus (FFM using high resolution spectral domain optical coherence tomography (HD-OCT; OCT 4000 Cirrus, Humphrey-Zeiss, San Leandro, CA.Methods: This was a prospective observational case series. Sixteen consecutive patients with STGD and FFM underwent a complete ophthalmologic examination. Optical coherence tomography examination was performed with HD-OCT, a high-speed (27,000 axial scans per second OCT system using spectral/Fourier domain detection, with an axial image resolution of 5 µm.Results: A total of 31 eyes were included in the study. Transverse loss of the PR layer in the foveal region was shown by HD-OCT. Twenty eyes with clinically evident central atrophy had a disruption of either the Verhoeff‘s membrane (VM or the layer corresponding to the interface of inner segment (IS and outer segment (OS of PR in the foveal region. Among these eyes, 12/20 eyes had a loss of the PR layer (loss of both VM and IS-OS interface in the foveal region. Eleven eyes (11/31 without clinically evident central atrophy had an intact interface of IS and OS of PR centrally. Moreover, we observed hyperreflective deposits: type 1 lesions located within the retinal pigment epithelium (RPE layer and at the level of the outer segments of PR, and type 2 lesions located at the level of the outer nuclear layer and clearly separated from the RPE layer. Type 1 lesions alone were associated with absence of loss of the PR layer in the foveal region in all eyes; type 2 lesions were always associated with presence of type 1 lesions, and often (8/12 eyes associated with loss of the PR layer within the foveal region. Mean best-corrected visual acuity (BCVA was significantly

Effect of cryopreservation and lyophilization on viability and growth of strict anaerobic human gut microbes.

Science.gov (United States)

Bircher, Lea; Geirnaert, Annelies; Hammes, Frederik; Lacroix, Christophe; Schwab, Clarissa

2018-04-17

Strict anaerobic gut microbes have been suggested as 'next-generation probiotics' for treating several intestinal disorders. The development of preservation techniques is of major importance for therapeutic application. This study investigated cryopreservation (-80°C) and lyophilization survival and storage stability (4°C for 3 months) of the strict anaerobic gut microbes Bacteroides thetaiotaomicron, Faecalibacterium prausnitzii, Roseburia intestinalis, Anaerostipes caccae, Eubacterium hallii and Blautia obeum. To improve preservation survival, protectants sucrose and inulin (both 5% w/v) were added for lyophilization and were also combined with glycerol (15% v/v) for cryopreservation. Bacterial fitness, evaluated by maximum growth rate and lag phase, viability and membrane integrity were determined using a standardized growth assay and by flow cytometry as markers for preservation resistance. Lyophilization was more detrimental to viability and fitness than cryopreservation, but led to better storage stability. Adding sucrose and inulin enhanced viability and the proportion of intact cells during lyophilization of all strains. Viability of protectant-free B. thetaiotaomicron, A. caccae and F. prausnitzii was above 50% after cryopreservation and storage and increased to above 80% if protectants were present. The addition of glycerol, sucrose and inulin strongly enhanced the viability of B. obeum, E. hallii and R. intestinalis from 0.03-2% in protectant-free cultures to 11-37%. This is the first study that quantitatively compared the effect of cryopreservation and lyophilization and the addition of selected protectants on viability and fitness of six strict anaerobic gut microbes. Our results suggest that efficiency of protectants is process- and species-specific. © 2018 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Financial viability of district mutual health insurance schemes of ...

African Journals Online (AJOL)

Since its implementation, unsubstantiated reports indicate increasing health care and administra-tive costs of the various DMHIS across the country without any corresponding increase in the premium level. We sought to assess the financial viability of the DMHIS in Lawra (LDMHIS) and Sissala East (SEDMHIS) districts, ...

The effects of storage conditions on the viability of ...

African Journals Online (AJOL)

Long-terms recoverability of enteropathogens is necessary for future epidemiological studies to screen stool samples when conditions do not permit immediate processing. The aim of this study was to determine the viability and the recoverability of three enteropathogens bacteria (Yersinia enterocolitica, Vibrio cholerae O: 1 ...

Effect of Pretreatments on Seed Viability During Fruit Development ...

African Journals Online (AJOL)

Fiifi Baidoo

picked from standing trees and/or forest floors, attain maximum viability and ... increase in germination potential (60%) of seeds treated with polyethylene .... Key: 60* = There was no germination 60 days after sowing; MC = Moisture content; Germ. ...... Paper presented at the pre-germplasm collection meeting on Irvingia.

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products.

Science.gov (United States)

Fiorentini, Angela Maria; Sawitzki, Maristela Cortez; Bertol, Teresinha Marisa; Sant'anna, Ernani S

2009-01-01

Viability of Staphylococcus xylosus isolated from artisanal sausages for application as starter cultures in meat products Viability of Staphylococcus xylosus strains AD1 and U5 isolated from natural fermented sausages was investigated as starter cultures in fermented sausages produced in the South Region of Brazil. The study demonstrated that the Staphylococcus xylosus strains AD1 and U5 showed significant growth during fermentation, stability over freeze-dried process, negative reaction for staphylococcal enterotoxins and viability for using as a single-strain culture or associated with lactic acid bacteria for production of fermented sausages.

Usefulness of radionuclide scintiphotography to evaluate preserved kidney viability

International Nuclear Information System (INIS)

Sato, Koshi; Yokota, Kazuhiko; Uchida, Hisanori

1987-01-01

GAMMA imaging of the renal cortical microcirculation is a safe and non-invasive method for assessment of kidney viability before transplantation. We used trifluoperazine (TFP), urokinase and verapamil from 24 to 120 hour kidney preservation in dogs. For these preserved kidneys, we used radionuuclide scintiphotography to evaluate kidney viability. After preservation, these kidneys were perfused with technitium -99m labeled microspheres, and imaging of the renal vasculature was obtained by scintigraphy. The distribution of the microspheres was assessed visually and by computer analysis. Modified Collins' solution perfused kidneys show very poor cortical uptake with marked increase in uptake in the hilar region after preservation. In contrast, cortical flow remained relatively well preserved in kidneys perfused and preserved by use of modified Collins' solotion with TFP, urokinase and urokinase + verapamil. There was a direct correlation between these results and the capacity of kidneys treated in the same fashion to sustain life after retransplantation into the original host. (author)

Equine ovarian tissue viability after cryopreservation and in vitro culture

Science.gov (United States)

The efficiency of several cryoprotective agents were compared using both slow-freezing and vitrification methods. Results indicate that the viability of ovarian tissue cells increases when DMSO (slow-freezing) and ethylene glycol (vitrification) are used....

Viability and growth characteristics of Lactobacillus in soymilk supplemented with B-vitamins.

Science.gov (United States)

Ewe, Joo-Ann; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

2010-02-01

Ten strains of Lactobacillus were evaluated for their viability in soymilk. Lactobacillus acidophilus ATCC 314, L. acidophilus FTDC 8833, L. acidophilus FTDC 8633 and L. gasseri FTDC 8131 displayed higher viability in soymilk and were thus selected to be evaluated for viability and growth characteristics in soymilk supplemented with B-vitamins. Pour plate analyses showed that the supplementation of all B-vitamins studied promoted the growth of lactobacilli to a viable count exceeding 7 log CFU/ml. alpha-Galactosidase specific activity of lactobacilli as determined spectrophotometrically showed an increase upon supplementation of B-vitamins. High-performance liquid chromatography analyses revealed that this led to increased hydrolysis of soy oligosaccharides and subsequently higher utilization of simple sugars. Production of organic acids as determined via high-performance liquid chromatography also showed an increase, accompanied by a decrease in pH of soymilk. Additionally, the supplementation of B-vitamins also promoted the synthesis of riboflavin and folic acid by lactobacilli in soymilk. Our results indicated that B-vitamin-supplemented soymilk is a good proliferation medium for strains of lactobacilli.

Encapsulation in alginate-skim milk microspheres improves viability of Lactobacillus bulgaricus in stimulated gastrointestinal conditions.

Science.gov (United States)

Pan, Ling-Xia; Fang, Xiu-Juan; Yu, Zhen; Xin, Yang; Liu, Xiao-Ying; Shi, Lu-E; Tang, Zhen-Xing

2013-05-01

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) was encapsulated in alginate-skim milk microspheres. Characteristics of encapsulated L. bulgaricus, such as pH stability, bile stability, storage stability and release property, were studied in this paper. The viability of free L. bulgaricus was not observed after 1 min in simulated gastric fluids (SGF) at pH 2.5 or 2.0. Compared with that of free L. bulgaricus, the viability of encapsulated L. bulgaricus only decreased 0.7 log CFU/g and 2 log CFU/g after 2.0 h incubation in SGF at pH 2.5 and pH 2.0, respectively. L. bulgaricus was also sensitive to bile solution. The viability of free L. bulgaricus was fully lost after 1 h incubation in 1 and 2% bile solution, while the viability of encapsulated L. bulgaricus was only lost 2 log CFU/g and 2.6 log CFU/g in 1 and 2% bile solution at the same time, respectively. Encapsulated L. bulgaricus could be completely released from microspheres in simulated intestinal fluid (pH 6.8) within 2 h. The viability of encapsulated L. bulgaricus retained around 8 log CFU/g when stored at 4°C for 30 days. The current encapsulation technique enables a large proportion of L. bulgaricus to remain good bioactive in a simulated gastrointestinal tract environment.

Pollen viability and its effect on fruit set of oil palm (Elaeis guineensis Jacq.

Directory of Open Access Journals (Sweden)

ALFIN WIDIASTUTI

2008-01-01

Full Text Available The research was aimed at studying (1 the decline of pollen viability during storage, and (2 the effect of pollen amount on fruit set of oil palm (Elaeis guineensis Jacq.. The experiment was conducted at PT. Dami Mas Sejahtera and PT. Sinar Mas Agro Resource and Technology (SMART Tbk, Riau from February to August 2004. The first experiment was investigated up to six months storage period in the refrigerator, whereas in the second experiment a randomized complete block design with two factors was used: length of storage, i.e. 0, 1 and 2 months and amount of pollen, i.e. 0.022, 0.044, 0.066, 0.088, and 0.11 g mixed with powder to 10g to pollinate an inflorescence. The result showed that the viability of pollen started to decline three months after storage from about 92% to 83%, and declined to about 75% after six months of storage. Result of the second experiment showed that storage of pollen up to two months did not affect percentage of normal fruit, although the percentage of parthenocarpic fruits was decreased. This could be due to the high viability of pollen as the viability was remained high (about 90% after being stored for two months in the refrigerator. Pollen with high viability could be used in a smaller amount to pollinate a female inflorescence without affecting fruit set of about 70-76%.SD037 had a higher reproductive success than SD038 and SD39.

Noninvasive assessment of tissue-engineered graft viability by oxygen-17 magnetic resonance spectroscopy.

Science.gov (United States)

Einstein, Samuel A; Weegman, Bradley P; Kitzmann, Jennifer P; Papas, Klearchos K; Garwood, Michael

2017-05-01

Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy ( 17 O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with 17 O 2 can also enable measurements of TEG viability. Macroencapsulated TEGs containing βTC3 murine insulinoma cells were prepared with three fractional viabilities and provided with 17 O 2 . Cellular metabolism of 17 O 2 into nascent mitochondrial water (H 2 17 O) was monitored by 17 O-MRS and, from the measured data, OCR was calculated. For comparison, OCR was simultaneously measured on a separate, but equivalent sample of cells with a well-established stirred microchamber technique. OCR measured by 17 O-MRS agreed well with measurements made in the stirred microchamber device. These studies confirm that 17 O-MRS can quantify TEG viability noninvasively. Biotechnol. Bioeng. 2017;114: 1118-1121. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Density, Viability Conidia And Symptoms of Metarhizium anisopliae infection on Oryctes rhinoceros larvae

Science.gov (United States)

Indriyanti, D. R.; Putri, R. I. P.; Widiyaningrum, P.; Herlina, L.

2017-04-01

M. anisopliae is parasitic fungus on insect pests; it is used as a biocontrol agent. M. anisopliae can be propagated on maize or rice substrate. M. anisopliae is currently sold in the form of kaolin powder formulations. Before it is used to check the density, viability and pathogenicity of M. anisopliae. However the problem is the kaolin powder very soft, so it difficult to distinguish between kaolin and conidia. This article gives information on how to calculate conidia density, viability and symptoms of M. anisopliae infection on Oryctes rhinoceros larvae. The study was conducted in the laboratory to determine the density and viability. The pathogenicity testing was done using pots. The Pot is containing soil substrate mixed with M. Anispoliae and ten tails O. Rhinoceros larvae per pot. The results showed that the density of M. anisopliae conidia was 1.81 x 108 conidia mL-1 and the viability was 94% within 24 hours. The larval mortality began to emerge in the 1st week, and all larvae died at the sixth week. The symptom of M. anisopliae infection on Oryctes rhinoceros larvae, there was a black spot on the larval integument. The larvae movements become slow and poor appetite; it will die within 3-7 days. The larvae die hard, and the white hyphae grow on the body surface that turns green.

In vitro pollen quantity, viability and germination tests in quince

African Journals Online (AJOL)

use

2011-11-21

Nov 21, 2011 ... rootstock pollens were collected in April from the unopened pink balloon-stage flowers on mature trees ..... their pollen characteristics to be used in cross breeding ... viability and germination levels for pistachio and terebinth in.

Gallic acid suppresses cell viability, proliferation, invasion and angiogenesis in human glioma cells

OpenAIRE

Lu, Yong; Jiang, Feng; Jiang, Hao; Wu, Kalina; Zheng, Xuguang; Cai, Yizhong; Katakowski, Mark; Chopp, Michael; To, Shing-Shun Tony

2010-01-01

Gallic acid, an organic acid, also known as 3,4,5-trihydroxybenzoic acid, is cytotoxic against certain cancer cells, without harming normal cells. The objective of this study is to evaluate whether gallic acid can inhibit glioma cell viability, proliferation, invasion and reduce glioma cell mediated angiogenesis. Treatment of U87 and U251n glioma cells with gallic acid inhibited cell viability in a dose- and time-dependent manner. BrdU and tube formation assays indicated that gallic acid sign...

Fluorescein diacetate for determination of cell viability in tissue-engineered skin.

Science.gov (United States)

Armour, Alexis D; Powell, Heather M; Boyce, Steven T

2008-03-01

Assurance of the quality of cultured skin substitutes (CSSs) currently relies on representative histology and determination of surface hydration, which provide limited sampling at selected points. To evaluate uniformity of cell density on the collagen matrices before clinical use, a field assessment of cell viability is advantageous. This study aimed to develop a field measure of cell viability in CSSs in vitro using fluorescein diacetate (FdA). CSSs were stained 3 days after keratinocyte inoculation using 0.04 mg/mL FdA followed by exposure to 366 nm of ultraviolet light. CSS fluorescence quantified using Metamorph image analysis was correlated with inoculation density, 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) values and histology of corresponding biopsies. CSS fluorescence correlated significantly with inoculation density (p < 0.001) and MTT values (p < 0.001) of biopsies collected immediately after FdA staining. Fluorescence at day 3 also predicted day 10 MTT values. No toxicity was detected in CSSs, and normal in vitro and in vivo histology was demonstrated after FdA exposure. In conclusion, measurement of intracellular fluorescence with FdA allows for the early, comprehensive measurement of cellular distributions and viability in engineered skin and may therefore facilitate quality assurance.

The reducibility of heLa cell viability by Sargassum polycystum extracts

Science.gov (United States)

Firdaus, M.; Setijawati, D.; Islam, I.; Nursyam, H.; Kartikaningsih, H.; Yufidasari, H. S.; Prihanto, A. A.; Nurdiani, R.; Jaziri, A. A.

2018-04-01

Cervical cancer is the second largest cause of death-related cancer in women. The efficacy of cancer drugs is still low. Bioactive of brown seaweed has been studied by in vitro and in vivo as anticancer. The aim of this study was to evaluate the cytotoxicity of Sargassum polycystum extracts on HeLa cell, to recognize bioactive on extract and estimate the interaction between the bioactive and target protein. S. polycystum was found from Talango Island waters and HeLa cell was obtained from Indonesian Science Institute. Sample was extracted by ethanol, ethyl acetate and hexane, concentrated and finally, extracts were assayed on HeLa cell. The viability of this cell was quantified on ELISA-Reader. The bioactive compounds of the extract were elucidated by GC-MS. The interaction between bioactive and target protein was evaluated by using in silico method. The result showed that the lowest viability of HeLa cell on n-hexane extracts treatment. The n-hexane extract of this seaweed contained benzenepropanoic acid. This compound reduced HeLa cell viability by reducing of thrombin concentration. In conclusion, the benzene propanoic acid of S. polycystum was the cytotoxic agent and it is potential agent for anti-cervical cancer.

Improvement on The Ellis and Roberts Viability Model

Directory of Open Access Journals (Sweden)

Guoyan Zhou

2016-05-01

Full Text Available With data sets of germination percent and storage time of seed lot of wheat and sorghum stored at three different storage temperature(t, °C with three different water content (m, % of seeds, together with data set of buckwheat and lettuce reported in literatures, the possibility that seed survival curve were transformed into line by survival proportion and the relationship that logarithm of average viability period (logp50 and standard deviation of seed death distribution in time (δwith t, m and interaction between t and m were analysed. Result indicated that survival proportion transformed seed survival curve to line were much easier than the probability adopted by Ellis and Roberts, and the most important factor affecting logp50 and δ of seed lot was interaction between t and m. Thus, Ellis and Roberts viability model were suggested to be improved as Ki=Vi-p/10K-CWT (t×m to predict longevity of seed lot with initial germination percent unknown, a new model of Gi/G0=A-P/10K-CWT(t×m was constructed to predict longevity of seed lot with initial germination percent already known.

UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis.

Science.gov (United States)

Hayes, Scott; Sharma, Ashutosh; Fraser, Donald P; Trevisan, Martine; Cragg-Barber, C Kester; Tavridou, Eleni; Fankhauser, Christian; Jenkins, Gareth I; Franklin, Keara A

2017-01-09

Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis [1]. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling [2-5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [6-8], and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90) [9]. High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) [11] strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of radiation dosage changes on the cell viability and the apoptosis induction on normal and tumorigenic cells

International Nuclear Information System (INIS)

Park, In Woo; Choi, Soon Chul; Lee, Sam Sun; Heo, Min Suk

1999-01-01

The study was aimed to detect the differences in the cell viability and the apoptosis induction after irradiation on normal and tumorigenic cells. The study, that was generated for two human normal cells (RHEK, HGF-1) and two human tumor cells (KB, HT-1080), was tested using MTT assay at 1 day and 3 day after irradiation and TUNEL assay under confocal laser scanning microscope at 1 day after irradiation. Single irradiation of 0.5, 1, 2, 4, and 8 Gy were applied to the cells. The two fractions of 1, 2, 4, and 8 Gy were separated with a 4 hour time interval. The irradiation was done with 5.38 Gy/min dose rate using Cs-137 irradiator at room temperature. 1. In 3-day group, the cell viability of HGF-1 cell was significantly decreased at 2, 4 and 8 Gy irradiation, the cell viability of KB cell was significantly decreased at 8 Gy irradiation and the cell viability of HT-1080 cell was significantly decreased at 4 and 8 Gy irradiation. 2. There was significant difference between RHEK and KB cell line in the cell viability of 3-day group at 8 Gy irradiation. There was significant difference between RHEK and HGF-1 cell line in the cell viability of 3-day group at 4 and 8 Gy irradiation. 3. There was a significantly decreased cell viability in 3-day group than those in 1-day group at 2, 4 and 8 Gy on HGF-1 cell, at 4 and 8 Gy on HT-1080 cell, at 8 Gy on KB cell.4. We could detect DNA fragmented cells only on KB cell. Number of apoptotic cells of KB cell was significantly increased at 4 and 8 Gy irradiation. However, there was no correlation between cell viability and apoptosis.5. On all 4 cell lines, there were no differences between single and split irradiation method in cell viability and apoptosis.

Human periodontal ligament cell viability in milk and milk substitutes.

Science.gov (United States)

Pearson, Robert M; Liewehr, Frederick R; West, Leslie A; Patton, William R; McPherson, James C; Runner, Royce R

2003-03-01

The purpose of this study was to determine the efficacy of several milk substitutes compared to whole milk in maintaining the viability of human periodontal ligament (PDL) cells on avulsed teeth. PDL cells were obtained from freshly extracted, healthy third molars and cultured in Eagle's minimal essential media (EMEM). The cells were plated onto 24-well culture plates and allowed to attach for 24 h. EMEM was replaced with refrigerated whole milk (positive control), reconstituted powdered milk, evaporated milk, or one of two baby formulas (Similac or Enfamil). Tap water served as the negative control. Tissue culture plates were incubated with the experimental media at 37 degrees C for 1, 2, 4, or 8 h. Cell viability was determined by a cell proliferation assay (CellTiter 96 AQ Assay), with absorbance read at 450 nM. A two-way ANOVA (p effect on PDL cell viability between any of the materials and whole milk. At 2 h, Enfamil and Similac performed significantly better than whole milk, whereas evaporated milk performed worse. At 4 h, Enfamil performed better than whole milk, whereas all other milk substitutes performed worse. At 8 h, all substitutes performed worse than whole milk. These results suggest that Enfamil, which is supplied in powder form that does not require special storage and has a shelf life of 18 months, is a more effective storage medium for avulsed teeth than pasteurized milk for at least 4 h.

Sphingosine kinase activity is not required for tumor cell viability.

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Karen Rex

Full Text Available Sphingosine kinases (SPHKs are enzymes that phosphorylate the lipid sphingosine, leading to the formation of sphingosine-1-phosphate (S1P. In addition to the well established role of extracellular S1P as a mitogen and potent chemoattractant, SPHK activity has been postulated to be an important intracellular regulator of apoptosis. According to the proposed rheostat theory, SPHK activity shifts the intracellular balance from the pro-apoptotic sphingolipids ceramide and sphingosine to the mitogenic S1P, thereby determining the susceptibility of a cell to apoptotic stress. Despite numerous publications with supporting evidence, a clear experimental confirmation of the impact of this mechanism on tumor cell viability in vitro and in vivo has been hampered by the lack of suitable tool reagents. Utilizing a structure based design approach, we developed potent and specific SPHK1/2 inhibitors. These compounds completely inhibited intracellular S1P production in human cells and attenuated vascular permeability in mice, but did not lead to reduced tumor cell growth in vitro or in vivo. In addition, siRNA experiments targeting either SPHK1 or SPHK2 in a large panel of cell lines failed to demonstrate any statistically significant effects on cell viability. These results show that the SPHK rheostat does not play a major role in tumor cell viability, and that SPHKs might not be attractive targets for pharmacological intervention in the area of oncology.

Determination of seed viability of eight wild Saudi Arabian species by germination and X-ray tests.

Science.gov (United States)

Al-Turki, Turki A; Baskin, Carol C

2017-05-01

Our purpose was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of eight wild species ( Salvia spinosa , Salvia aegyptiaca , Ochradenus baccatus , Ochradenus arabicus , Suaeda aegyptiaca , Suaeda vermiculata , Prosopisfarcta and Panicumturgidum ) from Saudi Arabia. Several days were required to determine viability of all eight species via germination tests, while immediate results on filled/viable seeds were obtained with the X-ray test. Seeds of all the species, except Sa.aegyptiaca , showed high viability in both the germination (98-70% at 25/15 °C, 93-66% at 35/25 °C) and X-ray (100-75%) test. Furthermore, there was general agreement between the germination (10% at 25/15 °C and 8% at 35/25 °C) and X-ray (5%) tests that seed viability of Sa.aegyptiaca was very low, and X-ray analysis revealed that this was due to poor embryo development. Seeds of P.farcta have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (98% at 25/15 °C and 93% at 35/25 °C) and X-ray (98%) test. Most of the nongerminated seeds of the eight species except those of Sa.aegyptiaca were alive as judged by the tetrazolium test (TZ). Thus, for the eight species examined, the X-ray test was a good and rapid predictor of seed viability.

Population Viability of Avian Endangered Species: the PVAvES Program

National Research Council Canada - National Science Library

Melton, Robert

2001-01-01

.... The program is designed to assess the viability of endangered bird species populations on U.S. Army lands. It also facilitates the comparison of alternative ecological scenarios based on different assumptions about the effects of natural or human...

[New valvular homografts. Prospects and limits of their viability. Report of 42 implantations].

Science.gov (United States)

Bloch, G; Mesnildrey, P; Hanotel, M C; Heurtematte, Y; Cachera, J P; Paul, M; Astier, A; Beaujean, F; Dubertret, L; Galle, P

1990-10-01

The regain of interest in aortic homograft bioprostheses is related to the prospects of improved viability resulting from explanation from organ donors, preservation in rich tissue culture media, together with the progress made in techniques of cryopreservation. Viability studies examining morphology of electron microscopy and tests of tissue culture confirm this notion of longer viability. These properties raise hopes of satisfactory long-term results while acknowledging outstanding antigenic problems which require strict A-B-O system compatibility. The results of a preliminary series of 42 valve homografts implanted at Henri Mondor Hospital over the last 5 years are reported. Twenty-one bioprostheses were implanted on the right side in congenital heart disease with good results in every case. Twenty-one were implanted in the aortic position in children and show no signs of degeneration as yet. One poor result was related to a technical error in calibration. The rebirth of this technique raises certain hopes, especially in aortic valve replacement.

Variation of weigh and viability of seeds of Pinus tropicalis from different populations

Directory of Open Access Journals (Sweden)

Marta Bonilla Vichot

2014-06-01

Full Text Available Pinus tropicalis Morelet is endemic in the province of Pinar del Rio and Isla de la Juventud. In this paper the variation is evaluated in weight and viability of seeds from 4 seed areas of the province of Pinar del Rio, Cuba, which were harvested in July and stored for five months at room temperature until They were made to the corresponding analysis. Samples of each of the sources weretaken to determine the weight of 1000 seeds, as established methodology ISTA (1993. Viability was also determined from the tetrazolium Test. It was observed that the individual weight of the seeds of Pinus tropicalis has 0,0051g values to 0,050g, while the average weight of 1000 seeds shows variation by origin, showing the greatest weight to the seeds from the seed mass Ceja del Negro (orchard seedling genetically enhanced trees, which directly influences the quality of seeds. The viability was also superior in the origin of Ceja del Negro.

An easy 'one tube' method to estimate viability of Cryptosporidium oocysts using real-time qPCR

NARCIS (Netherlands)

Paziewska-Harris, A.; Schoone, G.; Schallig, H. D. F. H.

2016-01-01

Viability estimation of the highly resistant oocysts of Cryptosporidium remains a key issue for the monitoring and control of this pathogen. We present here a simple 'one tube' quantitative PCR (qPCR) protocol for viability estimation using a DNA extraction protocol which preferentially solubilizes

Nanofibrous Chitosan-Polyethylene Oxide Engineered Scaffolds: A Comparative Study between Simulated Structural Characteristics and Cells Viability

Directory of Open Access Journals (Sweden)

Mohammad Kazemi Pilehrood

2014-01-01

Full Text Available 3D nanofibrous chitosan-polyethylene oxide (PEO scaffolds were fabricated by electrospinning at different processing parameters. The structural characteristics, such as pore size, overall porosity, pore interconnectivity, and scaffold percolative efficiency (SPE, were simulated by a robust image analysis. Mouse fibroblast cells (L929 were cultured in RPMI for 2 days in the presence of various samples of nanofibrous chitosan/PEO scaffolds. Cell attachments and corresponding mean viability were enhanced from 50% to 110% compared to that belonging to a control even at packed morphologies of scaffolds constituted from pores with nanoscale diameter. To elucidate the correlation between structural characteristics within the depth of the scaffolds’ profile and cell viability, a comparative analysis was proposed. This analysis revealed that larger fiber diameters and pore sizes can enhance cell viability. On the contrary, increasing the other structural elements such as overall porosity and interconnectivity due to a simultaneous reduction in fiber diameter and pore size through the electrospinning process can reduce the viability of cells. In addition, it was found that manipulation of the processing parameters in electrospinning can compensate for the effects of packed morphologies of nanofibrous scaffolds and can thus potentially improve the infiltration and viability of cells.

Coconut milk and probiotic milk as storage media to maintain periodontal ligament cell viability: an in vitro study.

Science.gov (United States)

Saini, Divya; Gadicherla, Prahlad; Chandra, Prakash; Anandakrishna, Latha

2017-06-01

The viability of periodontal ligament (PDL) cells is a significant determinant of the long-term prognosis of replanted avulsed teeth. A storage medium is often required to maintain the viability of these cells during the extra-alveolar period. Many studies have been carried out to search for the most suitable storage medium for avulsed teeth, but an ideal solution has not yet been found. The purpose of the study was to compare and analyze the ability of coconut milk and probiotic milk to maintain PDL cell viability. In an in vitro setting, 69 caries free human premolars with normal periodontium that had been extracted for orthodontic purposes were randomly divided into two experimental groups on the basis of storage media used (i.e., coconut milk or probiotic milk) and a Hanks' balanced salt solution (HBSS) control group (23 samples per group). Immediately after extraction, the teeth were stored dry for 20 min and then immersed for 30 min in one of the storage media. The teeth were then subjected to collagenase-dispase assay and labeled with 0.5% trypan blue staining solution for determination of cell viability. The number of viable cells was counted under a light microscope and statistically analyzed using anova and post hoc Tukey test (P ≤ 0.05). Statistical analysis demonstrated there was a significant difference (P coconut milk and probiotic milk as well as HBSS in maintaining cell viability. However, there was no significant difference between probiotic milk and HBSS in ability to maintain PDL cell viability (P > 0.05). Coconut milk may not be suitable as an interim transport media due to poor maintenance of cell viability. However, probiotic milk was able to maintain PDL cell viability as well as HBSS. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Allium White Rot Suppression with Composts and Trichoderma viride in Relation to Sclerotia Viability.

Science.gov (United States)

Coventry, E; Noble, R; Mead, A; Marin, F R; Perez, J A; Whipps, J M

2006-09-01

ABSTRACT Allium white rot (AWR) is a serious disease of Allium spp. caused by the sclerotium-forming fungus Sclerotium cepivorum. This work has examined the effects of onion waste compost (OWC) and spent mushroom compost (SMC), with and without Trichoderma viride S17A, on sclerotia viability and AWR in glasshouse and field experiments. Incorporation of OWC into soil reduced the viability of sclerotia and the incidence of AWR on onion plants in glasshouse pot bioassays, whereas SMC or T. viride S17A only reduced incidence of AWR. In two field trials, OWC reduced sclerotia viability and was as effective in reducing AWR as a fungicide (Folicur, a.i. tebuconazole). Field application of SMC had no effect on sclerotia viability and did not control AWR. However, the addition of T. viride S17A to SMC facilitated proliferation of T. viride S17A in the soil and increased the healthy onion bulb yield. The results indicate two mechanisms for the suppression of AWR: (i) reduction in the soil population of viable sclerotia, which may be due to volatile sulfur compounds detected in OWC but absent in SMC, and (ii) prevention of infection of onion plants from sclerotia following amendment of soil with OWC, SMC, or T. viride S17A.

[Performance of Thallium 201 rest-redistribution spect to predict viability in recent myocardial infarction].

Science.gov (United States)

Coll, Claudia; González, Patricio; Massardo, Teresa; Sierralta, Paulina; Humeres, Pamela; Jofré, Josefina; Yovanovich, Jorge; Aramburú, Ivonne; Brugère, Solange; Chamorro, Hernán; Ramírez, Alfredo; Kunstmann, Sonia; López, Héctor

2002-03-01

The detection of viability after acute myocardial infarction is primordial to select the most appropriate therapy, to decrease cardiac events and abnormal remodeling. Thallium201 SPECT is one of the radionuclide techniques used to detect viability. To evaluate the use of Thallium201 rest-redistribution SPECT to detect myocardial viability in reperfused patients after a recent myocardial infarction. Forty one patients with up to of 24 days of evolution of a myocardial infarction were studied. All had angiographically demonstrated coronary artery disease and were subjected to a successful thrombolysis, angioplasty or bypass grafting. SPECT Thallium201 images were acquired at rest and after 4 h of redistribution. These results were compared with variations in wall motion score, studied at baseline and after 3 or 4 months with echocardiography. The sensitivity of rest-redistribution Thallium201 SPECT, to predict recovery of wall motion was 91% when patient analysis was performed and 79% when segmental analysis was done in the culprit region. The figures for specificity were 56 and 73% respectively. Rest-distribution Thallium201 SPECT has an excellent sensitivity to predict myocardial viability in recent myocardial infarction. The data obtained in this study is similar to that reported for chronic coronary artery disease.

Viability and Management Targets of Mediterranean Demersal Fisheries: The Case of the Aegean Sea.

Directory of Open Access Journals (Sweden)

George Tserpes

Full Text Available Management of the Mediterranean demersal stocks has proven challenging mainly due to the multi-species character of the fisheries. In the present work, we focus on the multi-species demersal fisheries of the Aegean Sea (eastern Mediterranean aiming to study the effects of different management measures on the main commercial stocks, as well as to explore the economic viability of the fisheries depending upon these resources, by means of simulated projections. Utilizing the limited available data, our results demonstrated that, under the current exploitation pattern, the economic viability of the fleets is threatened, particularly if fuel prices increase. Additionally, the biological targets set for the most exploited species, such as hake, will not be met under the current management regime. The projections also showed that the only management scenario under which both resource sustainability and economic viability of the fisheries are ensured is the decrease of fleet capacity in terms of vessel numbers. In this case, however, measures to support the fisheries-dependent communities need to be implemented to prevent the collapse of local economies due to employment decrease. Scenarios assuming selectivity improvements would be also beneficial for the stocks but they showed low economic performance and their application would threaten the viability of the fleets, particularly that of the trawlers.

Edaravone enhances the viability of ischemia/reperfusion flaps.

Science.gov (United States)

Zhang, Dong-Yi; Kang, Shen-Song; Zhang, Zheng-Wen; Wu, Rui

2017-02-01

The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion (IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups: control group (n=16), IR group (n=16), and edaravone-treated IR group (n=16). An island flap at left lower abdomen (6.0 cm×3.0 cm in size), fed by the superficial epigastric artery and vein, was created in each rat of all the three groups. The arterial blood flow of flaps in IR group and edaravone-treated IR group was blocked for 10 h, and then the blood perfusion was restored. From 15 min before reperfusion, rats in the edaravone-treated IR group were intraperitoneally injected with edaravone (10 mg/kg), once every 12 h, for 3 days. Rats in the IR group and control group were intraperitoneally injected with saline, with the same method and frequency as the rats in the edaravone-treated IR group. In IR group and edaravone-treated IR group, samples of flaps were harvested after reperfusion of the flaps for 24 h. In the control group, samples of flaps were harvested 34 h after creation of the flaps. The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were determined, and changes in organizational structure and infiltration of inflammatory cells were observed by hematoxylin-eosin (HE) staining, apoptotic cells of vascular wall were marked by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and the apoptotic rate of cells in vascular wall was calculated. The ultrastructural changes of vascular endothelial cells were observed by transmission electron microscopy (TEM). Seven days after the operation, we calculated the flap viability of each group, and marked vessels of flaps by immunohistochemical staining for calculating the average number of subcutaneous vessels. The results showed that the content of MDA, the number of multicore inflammatory cells and apoptotic rate of cells in vascular wall

Mechanism for Selective Synaptic Wiring of Rod Photoreceptors into the Retinal Circuitry and Its Role in Vision.

Science.gov (United States)

Cao, Yan; Sarria, Ignacio; Fehlhaber, Katherine E; Kamasawa, Naomi; Orlandi, Cesare; James, Kiely N; Hazen, Jennifer L; Gardner, Matthew R; Farzan, Michael; Lee, Amy; Baker, Sheila; Baldwin, Kristin; Sampath, Alapakkam P; Martemyanov, Kirill A

2015-09-23

In the retina, rod and cone photoreceptors form distinct connections with different classes of downstream bipolar cells. However, the molecular mechanisms responsible for their selective connectivity are unknown. Here we identify a cell-adhesion protein, ELFN1, to be essential for the formation of synapses between rods and rod ON-bipolar cells in the primary rod pathway. ELFN1 is expressed selectively in rods where it is targeted to the axonal terminals by the synaptic release machinery. At the synapse, ELFN1 binds in trans to mGluR6, the postsynaptic receptor on rod ON-bipolar cells. Elimination of ELFN1 in mice prevents the formation of synaptic contacts involving rods, but not cones, allowing a dissection of the contributions of primary and secondary rod pathways to retinal circuit function and vision. We conclude that ELFN1 is necessary for the selective wiring of rods into the primary rod pathway and is required for high sensitivity of vision. Copyright © 2015 Elsevier Inc. All rights reserved.

Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4-/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo.

Science.gov (United States)

De Silva, Samantha R; Charbel Issa, Peter; Singh, Mandeep S; Lipinski, Daniel M; Barnea-Cramer, Alona O; Walker, Nathan J; Barnard, Alun R; Hankins, Mark W; MacLaren, Robert E

2016-11-01

Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4 -/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4 -/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.

Effect of alcohol on insulin secretion and viability of human pancreatic islets

Directory of Open Access Journals (Sweden)

Nikolić Dragan

2017-01-01

Full Text Available Introduction/Objective. There are controversial data in the literature on the topic of effects of alcohol on insulin secretion, apoptosis, and necrosis of the endocrine and exocrine pancreas. The goal of this research was to determine how alcohol affects the insulin secretion and viability of human adult pancreatic islets in vitro during a seven-day incubation. Methods. Human pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated in Roswell Park Memorial Institute (RPMI medium containing alcohol (10 μl of alcohol in 100 ml of medium. Insulin stimulation index (SI and viability of the islets were determined on the first, third, and seventh day of cultivation. Results. Analysis of the viability of the islets showed that there wasn’t significant difference between the control and the test group. In the test group, viability of the cultures declined with the time of incubation. SI of the test group was higher compared to the control group, by 50% and 25% on the first and third day of cultivation, respectively. On the seventh day, insulin secretion was reduced by 25%. The difference was not statistically significant (p > 0.05. In the test group, significant decline in insulin secretion was found on the third and seventh day of incubation (p ≤ 0.05. Conclusion. Alcohol can increase or decrease insulin secretion of islets cultures, which may result in an inadequate response of pancreatic β-cells to blood glucose, leading to insulin resistance, and increased risk of developing type 2 diabetes. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 41002

Testing a dual-fluorescence assay to monitor the viability of filamentous cyanobacteria.

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Johnson, Tylor J; Hildreth, Michael B; Gu, Liping; Zhou, Ruanbao; Gibbons, William R

2015-06-01

Filamentous cyanobacteria are currently being engineered to produce long-chain organic compounds, including 3rd generation biofuels. Because of their filamentous morphology, standard methods to quantify viability (e.g., plate counts) are not possible. This study investigated a dual-fluorescence assay based upon the LIVE/DEAD® BacLight™ Bacterial Viability Kit to quantify the percent viability of filamentous cyanobacteria using a microplate reader in a high throughput 96-well plate format. The manufacturer's protocol calls for an optical density normalization step to equalize the numbers of viable and non-viable cells used to generate calibration curves. Unfortunately, the isopropanol treatment used to generate non-viable cells released a blue pigment that altered absorbance readings of the non-viable cell solution, resulting in an inaccurate calibration curve. Thus we omitted this optical density normalization step, and carefully divided cell cultures into two equal fractions before the isopropanol treatment. While the resulting calibration curves had relatively high correlation coefficients, their use in various experiments resulted in viability estimates ranging from below 0% to far above 100%. We traced this to the apparent inaccuracy of the propidium iodide (PI) dye that was to stain only non-viable cells. Through further analysis via microplate reader, as well as confocal and wide-field epi-fluorescence microscopy, we observed non-specific binding of PI in viable filamentous cyanobacteria. While PI will not work for filamentous cyanobacteria, it is possible that other fluorochrome dyes could be used to selectively stain non-viable cells. This will be essential in future studies for screening mutants and optimizing photobioreactor system performance for filamentous cyanobacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

Pollen viability of Salix myrtilloides L. – an endangered species in Poland

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Magdalena Pogorzelec

2016-12-01

Full Text Available Salix myrtilloides L. (swamp willow is the most endangered species among the boreal Salix species in Poland. The number and size of its population have been decreasing constantly since the 1990s. The main aim of the study was to determine the viability of collected S. myrtilloides pollen and optimal conditions for its in vitro germination. The pollen of S. myrtilloides was collected from 25 male individuals from a population growing in the mid-forest peat bog Dekowina (Sobibór Landscape Park in May 2014. Two methods were applied to estimate the viability of fresh and stored pollen: staining pollen with 2% acetocarmine solution and in vitro germinability. Various temperature (11°C, 23°C and light conditions as well as different concentrations of glucose (1%, 2.5%, 5%, or 7.5% were tested for the optimization of in vitro germination. We documented relatively high S. myrtilloides pollen viability. Pollen tube growth was found to be largely affected by both glucose content in the medium and thermal conditions during germination. Fresh pollen germinated most effectively on the medium with 2.5% glucose (stored pollen – in 5% glucose, at 23°C and in the presence of light. We conclude that pollen viability of S. myrtilloides does not seem to be a limiting factor for reproductive success. Moreover, the pollen is not sterile even after storage for 12 months. The S. myrtilloides individuals from the Dekowina peat bog produce viable pollen grains that are able to germinate and therefore it can be used to pollinate other populations present in the Polesie Lubelskie region for gene pool enrichment.

Image enhancement filters significantly improve reading performance for low vision observers

Science.gov (United States)

Lawton, T. B.

1992-01-01

As people age, so do their photoreceptors; many photoreceptors in central vision stop functioning when a person reaches their late sixties or early seventies. Low vision observers with losses in central vision, those with age-related maculopathies, were studied. Low vision observers no longer see high spatial frequencies, being unable to resolve fine edge detail. We developed image enhancement filters to compensate for the low vision observer's losses in contrast sensitivity to intermediate and high spatial frequencies. The filters work by boosting the amplitude of the less visible intermediate spatial frequencies. The lower spatial frequencies. These image enhancement filters not only reduce the magnification needed for reading by up to 70 percent, but they also increase the observer's reading speed by 2-4 times. A summary of this research is presented.

An evaluation of the effects of long term cryopreservation, cause of death, and time between death and donation on heart valve leaflet viability

International Nuclear Information System (INIS)

Strachan, K.

1999-01-01

The protocol for cryopreservation of allograft heart valves at the Donor Tissue Bank of Victoria was based on validation studies on the viability of the heart valve leaflets at the time of processing. The heart block is removed within 24 hours of death and the aor-tic and pulmonary valves trimmed immediately following retrieval. Following this processing, the valves are incubated in antibiotics at 30 degree C for 6 to 8 hours before being frozen in 10% DMSO at a controlled rate. A sample of tricuspid valve leaflet is placed in Krebs solution at the time of trimfning and is used for viability studies. Leaflet viability studies have been perfon-ned on all heart valves retrieved from 1993 to the present day at the Donor Tissue Bank of Victoria. Viability involves a qualitative assessment of the cellular outgrowth by leaflet fibroblasts, this assessment ranging from '-' for no outgrowth to '++++' for maximum outgrowth. Surgeons do not request valves with any particular viability and will use them whether they are viable or not. This evaluation was to determine the effects of long-term cryopreservation, cause of death, and also time lapse of heart removal following death on the viability of the retrieved leaflets. The aim of investigating the effects of long-term cryopreservation was to determine whether there was any correlation between initial viability and viability following storage for several months to several years. It was also decided to investigate whether there was any correlation between time length between death and heart retrieval and the viability. It was also thought that the cause of death may have had an effect on the viability, for example, did death by carbon monoxide poisoning have an effect on the viability of heart valve cells. Heart valves, which had been cryopreserved but could not be transplanted for various reasons were used to study the effects of cryopreservation in this study. These were thawed according to protocol and a sample of the valve

Nucleic acid stains as indicators of Giardia muris viability following cyst inactivation.

Science.gov (United States)

Taghi-Kilani, R; Gyürék, L L; Millard, P J; Finch, G R; Belosevic, M

1996-06-01

A reliable viability assay for Giardia is required for the development of disinfection process design criteria and pathogen monitoring by water treatment utilities. Surveys of single-staining nucleic acid dyes (stain dead parasites only), and double-staining vital dye kits from Molecular Probes (stain live and dead parasites) were conducted to assess the viability of untreated, heat-killed, and chemically inactivated Giardia muris cysts. Nucleic acid staining results were compared to those of in vitro excystation and animal infectivity. Nucleic acid stain, designated as SYTO-9, was considered the best among the single-staining dyes for its ability to stain dead cysts brightly and its relatively slow decay rate of visible light emission following DNA binding. SYTO-9 staining was correlated to animal infectivity. A Live/Dead BacLight was found to be the better of 2 double-staining viability kits tested. Logarithmic survival ratios based on SYTO-9 and Live/Dead BacLight were compared to excystation and infectivity results for G. muris cysts exposed to ozone or free chlorine. The results indicate that SYTO-9 and Live/Dead BacLight staining is stable following treatment of cysts with chemical disinfectants.

Influence of electrospun scaffolds prepared from distinct polymers on proliferation and viability of endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Matveeva, V. G., E-mail: matveeva-vg@mail.ru; Antonova, L. V., E-mail: antonova.la@mail.ru; Velikanova, E. A.; Sergeeva, E. A.; Krivkina, E. O.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S. [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, 650002 (Russian Federation)

2015-10-27

We compared electrospun nonwoven scaffolds from polylactic acid (PLA), polycaprolactone (PCL), and polyhydroxybutyrate/valerate (PHBV)/polycaprolactone (PHBV/PCL). The surface of PHBV/PCL and PCL scaffolds was highly porous and consisted of randomly distributed fibers, whilst the surface of PLA scaffolds consisted of thin straight fibers, which located more sparsely, forming large pores. Culture of EA.hy 926 endothelial cells on these scaffolds during 7 days and further fluorescent microscopy demonstrated that the surface of PHBV/PCL scaffolds was most favorable for efficient adhesion, proliferation, and viability of endothelial cells. The lowest proliferation rate and cell viability were detected on PLA scaffolds. Therefore, PHBV/PCL electrospun nonwoven scaffolds demonstrated the best results regarding endothelial cell proliferation and viability as compared to PCL and PLA scaffolds.

The economic and social viability of Tanzanian Wildlife Management Areas

DEFF Research Database (Denmark)

Homewood, Katherine; Bluwstein, Jevgeniy; Lund, Jens Friis

This policy brief contributes to assessing the economic and social viability of Tanzania’s Wildlife Management Areas (WMAs) through preliminary findings by the ‘Poverty and ecosystem Impacts of Tanzania’s Wildlife Management Areas’ (PIMA) project, focusing on benefits, costs, and their distribution...

Irregular Shelterwood Cuttings Promote Viability of European Yew Population Growing in a Managed Forest: A Case Study from the Starohorské Mountains, Slovakia

Directory of Open Access Journals (Sweden)

Denisa Sedmáková

2017-08-01

Full Text Available The increasing probability of Taxus baccata (L. decline given climate change brings forth many uncertainties for conservation management decisions. In this article, the authors present the effects of applying regeneration cuttings since the year 2000 on the viability of the understory yew population. By collecting data from a stand located at the centre of the largest population of European yew in Slovakia, containing approximately 160,000 individuals, and analysing tree-ring records from 38 sampled trees, the improved performance of yews, including stem growth, seed production, and number of regenerated individuals, was revealed. Thinning the canopy by removing 15% of the growing stock volume per decade, combined with the subsequent irregular shelterwood cuttings, was assessed as a useful strategy. Moreover, lower radial growth of females compared to males, but simultaneously their similar response to climate, suggests a possible trade-off between reproduction and growth. Release cuttings of up to 30% of the standing volume in the vicinity of the female trees, executed in the rainy summers following warmer winters, and consistent elimination of deer browsing, can further enhance the positive effects of applied cuts on yew viability. Overall, the suggested active measures could be considered as an effective option to preserve the unique biodiversity of calcareous beech-dominated forests in Central Europe.

[Fluorescein angiography and optical coherence tomography findings in central fundus of myopic patients].

Science.gov (United States)

Avetisov, S E; Budzinskaya, M V; Zhabina, O A; Andreeva, I V; Plyukhova, A A; Kobzova, M V; Musaeva, G M

2015-01-01

Myopia prevalence grows alike in many countries, including Russia, regardless of geographical and population conditions. to assess fundus changes in myopic patients at different ocular axial lengths by means of modern diagnostic tools. The study enrolled 97 patients (194 eyes) aged 45 ± 20.17 years with myopia of different degrees. Besides a standard ophthalmic examination, all patients underwent fundus fluorescein angiography and optical coherence tomography. The occurrence of retinal pigment epithelium (RPE) atrophy (diffuse or focal) has been shown to increase with increasing ocular axial length. Only 27 eyes (28.1%) appeared intact. As myopia progression implies axial growth of the eye, it is associated with a more severe decrease in choroid, RPE, and photoreceptor layer thicknesses: the longer the anterior-posterior axis, the thinner the above mentioned fundus structures. Age-related changes in the fundus are also likely to be more pronounced in longer axes. Myopic traction maculopathy, which in our case appeared the main cause of increased retinal thickness, was diagnosed in 105 eyes, "outer" macular retinoschisis--in 40 eyes. Thus, modern diagnostic tools, such as fluorescein angiography and optical coherence tomography, enable objective assessment of the central fundus.

Herniation of the retina in the central macula in an adult after iridocyclitis.

Science.gov (United States)

Guo, Qing; Pi, Yuli; Gao, Ting

2014-09-01

To report an unusual case of retinal hernia in the central macula in an adult after iridocyclitis. We report a case of a 46-year-old male who presented with blurred vision 2 weeks after complete resolution of acute iridocyclitis. Anterior segment and vitreous body examinations were unremarkable. Yellowish spots in the macular area were observed. Spectral domain optical coherence tomography (SD-OCT) imaging of the macula showed loss of the inner segment/outer segment (IS/OS) photoreceptor junction, with irregularity of the retinal pigment epithelium (RPE), and a V-shaped hernia of the retina into the choroid. The macular lesions emerged as mild window defects on fluorescein angiography and were visualized as hypofluorescent patches on all-phase indocyanine green angiography. At a one month follow-up, the best-corrected visual acuity improved to 20/20, which was followed by partial restoration of the IS/OS line, but a V-shaped hernia of the retina remained unchanged on SD-OCT. Ophthalmologists should be alert to the changes in OCT of the macula in patients after iridocyclitis and further research on the cause and possible predisposing factors for retinal herniation is warranted.

Measurement of the viability of stored red cells by the single-isotope technique using 51Cr. Analysis of validity

International Nuclear Information System (INIS)

Beutler, E.; West, C.

1984-01-01

A single-isotope 51 Cr method often is used to evaluate the viability of stored red cells. In this technique, the red cell mass is measured by back-extrapolation to time zero (t0) of the radioactivity of the blood between 5 and 20 minutes after infusion of the sample. If there is early destruction of stored cells, this method provides an overestimate of the red cell mass and, hence, of the viability of the stored cells. Freshly drawn red cells from normal donors were labeled with /sup 99m/Tc, and cells from the same donor which had been stored in citrate-phosphate-dextrose-adenine-one (CPDA-1) for periods ranging from 7 to 49 days were labeled with 51 Cr. A comparison of the ''true red cell mass'' as determined with /sup 99m/Tc with the back-extrapolated red cell mass from stored 51 Cr-labeled cells has made it possible to define the magnitude of error introduced by early loss of red cells. The overestimation of red cell mass and viability was diminished if only the 51 Cr radioactivity between 5 and 15 minutes after infusion was used in back-extrapolating to t0. The degree of overestimation of red cell mass was greatest when the red cell viability had declined to very low levels. However, in the entire range of 10 to 80 percent viability, the overestimate of viability was usually less than 4 percent. The overestimate of viability proved to be quite similar for all samples and may be taken into account when using the single-isotope technique for measurement of red cell viability

Comparison of the effect of three autogenous bone harvesting methods on cell viability in rabbits

Science.gov (United States)

Moradi Haghgoo, Janet; Arabi, Seyed Reza; Hosseinipanah, Seyyed Mohammad; Solgi, Ghasem; Rastegarfard, Neda; Farhadian, Maryam

2017-01-01

Background. This study was designed to compare the viability of autogenous bone grafts, harvested using different methods, in order to determine the best harvesting technique with respect to more viable cells. Methods. In this animal experimental study, three harvesting methods, including manual instrument (chisel), rotary device and piezosurgery, were used for harvesting bone grafts from the lateral body of the mandible on the left and right sides of 10 rabbits. In each group, 20 bone samples were collected and their viability was assessed using MTS kit. Statistical analyses, including ANOVA and post hoc Tukey tests, were used for evaluating significant differences between the groups. Results. One-way ANOVA showed significant differences between all the groups (P=0.000). Data analysis using post hoc Tukey tests indicated that manual instrument and piezosurgery had no significant differences with regard to cell viability (P=0.749) and the cell viability in both groups was higher than that with the use of a rotary instrument (P=0.000). Conclusion. Autogenous bone grafts harvested with a manual instrument and piezosurgery had more viable cells in comparison to the bone chips harvested with a rotary device. PMID:28748046

Viability and Biochemical Content Changes in Seed Storage of Jabon Putih (Anthocephalus Cadamba (Roxb Miq.

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Naning Yuniarti

2015-08-01

Full Text Available Seed deterioration is the process of deteriorated seed in view of viability that changed the physiological and chemical content. The aim of this research is to find out the effect of moisture content and storage on viability and biochemical content of jabon putih seed. Completely Randomized Design was used for decreasing moisture content based on seed drying time for 0, 24, 48, 72, 96, 120 hours, and Completely Randomized Factorial Design was used for the combination of moisture content (drying time for 0, 24, 48, 72, 96, 120 hours and room storage (ambient room, air-conditioned room, refrigerator. The results of this research are: (1 seed drying time and seed storage affected the change of seed viability and biochemical content, (2 seed drying time and seed storage influence significantly the value of moisture content, germination percentage, and biochemical content (lipid, carbohydrate, protein, (3 The longer time of seed drying and seed storage has decreased the seed moisture content, germination percentage, and the carbohydrate content, but it has increased the content of lipid and protein, and (4 the seeds were stored in refrigerator has better viability compared to dry cold storage and ambient room.