Protocols for Robust Herbicide Resistance Testing in Different Weed Species.

PubMed

Panozzo, Silvia; Scarabel, Laura; Collavo, Alberto; Sattin, Maurizio

2015-07-02

Robust protocols to test putative herbicide resistant weed populations at whole plant level are essential to confirm the resistance status. The presented protocols, based on whole-plant bioassays performed in a greenhouse, can be readily adapted to a wide range of weed species and herbicides through appropriate variants. Seed samples from plants that survived a field herbicide treatment are collected and stored dry at low temperature until used. Germination methods differ according to weed species and seed dormancy type. Seedlings at similar growth stage are transplanted and maintained in the greenhouse under appropriate conditions until plants have reached the right growth stage for herbicide treatment. Accuracy is required to prepare the herbicide solution to avoid unverifiable mistakes. Other critical steps such as the application volume and spray speed are also evaluated. The advantages of this protocol, compared to others based on whole plant bioassays using one herbicide dose, are related to the higher reliability and the possibility of inferring the resistance level. Quicker and less expensive in vivo or in vitro diagnostic screening tests have been proposed (Petri dish bioassays, spectrophotometric tests), but they provide only qualitative information and their widespread use is hindered by the laborious set-up that some species may require. For routine resistance testing, the proposed whole plant bioassay can be applied at only one herbicide dose, so reducing the costs.

Potential of endophytic fungi as biocontrol agents of Duponchelia fovealis (Zeller) (Lepidoptera:Crambidae).

PubMed

Amatuzzi, R F; Cardoso, N; Poltronieri, A S; Poitevin, C G; Dalzoto, P; Zawadeneak, M A; Pimentel, I C

2017-11-09

This study reports the first assessment of endophytic fungi isolated from strawberry leaves and selection of isolates for the control of Duponchelia fovealis, a new pest of strawberries. A total of 400 strawberry leaves of the cultivar 'Albion' were collected in four commercial farms. Leaves were disinfected, cut in fragments, and placed on Petri dishes containing potato dextrose agar media with tetracycline and incubated for 30 days. Following this time, 517 fungal colonies were isolated, and thirteen genera were identified: Cladosporium, Aspergillus, Nigrospora, Fusarium, Trichoderma, Chaetomium, Alternaria, Paecilomyces, Penicillium, Ulocladium, Bipolaris, Diaporthe, and Phoma. Eight isolates belonging to the genera Aspergillus, Diaporthe, Paecilomyces, and Cladosporium were selected for pathogenicity bioassays against third instar larvae of D. fovealis. Isolates of Paecilomyces induced the highest mortality rates.

The Blue Bottle Experiment--Simple Demonstration of Self-Organization.

ERIC Educational Resources Information Center

Adamcikova, L'ubica; Sevcik, Peter

1998-01-01

Explains a way of observing pattern formation in the Blue Bottle chemistry demonstration by pouring a solution containing sodium hydroxide, glucose, and dye into a Petri dish and placing the dish on an overhead projector. (WRM)

Overhead Projector Demonstrations: A Classroom Demonstration of Aliphatic Substitution.

ERIC Educational Resources Information Center

Perina, Ivo; Mihanovic, Branka

1989-01-01

Presents a halogen substitution of an alkane using a compartmentalized Petri dish or Conway dish on an overhead projector. Provides methodology and several modifications for different reactions. Uses hexane, methyl orange, bromine, and silver nitrate. (MVL)

Field measurements of dry deposition to spruce foliage and petri dishes in the Black Forest, F.R.G.

USGS Publications Warehouse

Shanley, J.B.

1989-01-01

Dry deposition fluxes Ca2+, Mg2+, K+, Mn2+, Pb2+ and SO42- to spruce foliage and petri dishes were measured in two high-elevation sites (>900 m) in the southern Black Forest, F.R.G., during 12 periods (2-7 days, each) from mid-September to mid-November, 1983, In situ extraction of deposited material from small spruce branches allowed repeated use of the same foliar collecting surfaces for a direct comparison of deposition between periods. Fluxes were corrected for leaching of internally cycled constituents using factors determined from serial extraction experiments. The ratio of flux to petri dishes vs foliage (P/F) was >1.0 for Ca2+, Pb2+ and SO42-, and somewhat 900 m) in the southern Black Forest, F.R.G., during 12 periods (2-7 days, each) from mid-September to mid-November, 1983. The ratio of flux to petri dishes vs foliage (P/F) was >1.0 for Ca2+, Pb2+, and SO42-, and somewhat <1.0 but more constant for Mg2+. Temporal variations in dry deposition fluxes at an exposed site near the industrialized Rhine Valley correlated with variations in total air particulate concentrations at a nearby air quality station. Deposition rates were comparable in magnitude but different in temporal pattern at a remote site in the Black Forest interior. Fluxes at each site reached a minimum during the period of 4-9 November when a regional air inversion confined pollutants to the Rhine Valley below the study sites. High fluxes accompanied the inversion break-up.

Calculations of the Acceleration of Centrifugal Loading on Adherent Cells

NASA Astrophysics Data System (ADS)

Chen, Kang; Song, Yang; Liu, Qing; Zhang, Chunqiu

2017-07-01

Studies have shown that the morphology and function of living cells are greatly affected by the state of different high acceleration. Based on the centrifuge, we designed a centrifugal cell loading machine for the mechanical biology of cells under high acceleration loading. For the machine, the feasibility of the experiment was studied by means of constant acceleration or variable acceleration loading in the Petri dish fixture and/or culture flask. Here we analyzed the distribution of the acceleration of the cells with the change of position and size of the culturing device quantitatively. It is obtained that Petri dish fixture and/or culture flask can be used for constant acceleration loading by experiments; the centripetal acceleration of the adherent cells increases with the increase of the distance between the rotor center of the centrifuge and the fixture of the Petri dish and the size of the fixture. It achieves the idea that the general biology laboratory can conduct the study of mechanical biology at high acceleration. It also provides a basis for more accurate study of the law of high acceleration on mechanobiology of cells.

Microstamped Petri Dishes for Scanning Electrochemical Microscopy Analysis of Arrays of Microtissues

PubMed Central

Sridhar, Adithya; de Boer, Hans L.; van den Berg, Albert; Le Gac, Séverine

2014-01-01

While scanning electrochemical microscopy (SECM) is a powerful technique for non-invasive analysis of cells, SECM-based assays remain scarce and have been mainly limited so far to single cells, which is mostly due to the absence of suitable platform for experimentation on 3D cellular aggregates or microtissues. Here, we report stamping of a Petri dish with a microwell array for large-scale production of microtissues followed by their in situ analysis using SECM. The platform is realized by hot embossing arrays of microwells (200 μm depth; 400 μm diameter) in commercially available Petri dishes, using a PDMS stamp. Microtissues form spontaneously in the microwells, which is demonstrated here using various cell lines (e.g., HeLa, C2C12, HepG2 and MCF-7). Next, the respiratory activity of live HeLa microtissues is assessed by monitoring the oxygen reduction current in constant height mode and at various distances above the platform surface. Typically, at a 40 μm distance from the microtissue, a 30% decrease in the oxygen reduction current is measured, while above 250 μm, no influence of the presence of the microtissues is detected. After exposure to a model drug (50% ethanol), no such changes in oxygen concentration are found at any height in solution, which reflects that microtissues are not viable anymore. This is furthermore confirmed using conventional live/dead fluorescent stains. This live/dead assay demonstrates the capability of the proposed approach combining SECM and microtissue arrays formed in a stamped Petri dish for conducting cellular assays in a non-invasive way on 3D cellular models. PMID:24690887

Gods, Germs, and Petri Dishes: Toward a Nonsecular Medical Anthropology.

PubMed

Roberts, Elizabeth F S

2016-01-01

This commentary calls on medical anthropology to become programmatically non-secular. Despite recent anthropological critiques of secularity, within and outside of anthropology, most contemporary medical anthropologists continue to leave deities and religiosity out of their examinations of healing practices, especially in their accounts of biomedicine. Through a critical, relational constructionist lens, which traces how all entities are both constructed and real, a non-secular medical anthropology would insist that when deities are part of medical practice, they are integral to analysis. Importantly then, within the symmetrical nature of this same constructionist lens, biomedical entities like germs and petri dishes need to be accounted for just as much as deities.

Antagonism of Trichoderma isolates against Leucoagaricus gongylophorus (Singer) Möller.

PubMed

do Nascimento, Mariela Otoni; de Almeida Sarmento, Renato; Dos Santos, Gil Rodrigues; de Oliveira, Cléia Almeida; de Souza, Danival José

2017-08-01

Filamentous fungi from the genus Trichoderma are commonly found in soil. They are considered facultative mycoparasites, and are antagonists of other fungi such as the cultivar of leaf-cutting ants (Leucoagaricus gongylophorus). The aim of the present study was to bioprospect Trichoderma spp. from different soils collected from Gurupi, Tocantins, Brazil, for antagonistic effects against the mutualistic fungus of leaf-cutting ants. To isolate filamentous fungi, samples were collected from six locations. Preliminarily, isolates were identified by morphological analysis as belonging to Trichoderma. Trichoderma spp. had their internal transcribed spacer region (ITS) of ribosomal RNA genes (rRNA) sequenced to confirm species-level taxonomy. L. gongylophorus was isolated from a laboratory ant colony. Antagonistic properties of seven isolates of Trichoderma against L. gongylophorus were measured using paired disks in Petri dishes with potato dextrose agar medium (PDA). All Trichoderma isolates inhibited the growth of L. gongylophorus in Petri dishes. Isolate 2 of Trichoderma spirale group exhibited slow mycelial growth in the Petri dish, and a high rate of inhibition against L. gongylophorus. This isolate is a promising fungus for field tests of biological control methods for leaf-cutting ants. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Apparatus and process for microbial detection and enumeration

NASA Technical Reports Server (NTRS)

Wilkins, J. R.; Grana, D. (Inventor)

1982-01-01

An apparatus and process for detecting and enumerating specific microorganisms from large volume samples containing small numbers of the microorganisms is presented. The large volume samples are filtered through a membrane filter to concentrate the microorganisms. The filter is positioned between two absorbent pads and previously moistened with a growth medium for the microorganisms. A pair of electrodes are disposed against the filter and the pad electrode filter assembly is retained within a petri dish by retainer ring. The cover is positioned on base of petri dish and sealed at the edges by a parafilm seal prior to being electrically connected via connectors to a strip chart recorder for detecting and enumerating the microorganisms collected on filter.

Pt-coated cylindrical micropatterned honeycomb Petri dishes as an efficient TCO-free counter electrode in liquid junction photovoltaic devices

NASA Astrophysics Data System (ADS)

Dao, Van-Duong; Bui, Van-Tien; Choi, Ho-Suk

2018-02-01

The Pt layer deposited on a cylindrical micro cavity patterned Petri dish, which is produced using a one-step solvent-immersion phase separation, is fabricated for the first time as an FTO-free counter electrode (CE) for dye-sensitized solar cells (DSCs). Due to the high specific active surface area of the Pt-deposited honeycomb substrate CE, the efficiency of the DSC using the developed CE substrate is enhanced by 14.5% compared with the device using a Pt-sputtered flat substrate. This design strategy has potential in fabricating highly efficient and low-cost CE materials with FTO-free substrates for DSCs.

Selective sweeps in growing microbial colonies

NASA Astrophysics Data System (ADS)

Korolev, Kirill S.; Müller, Melanie J. I.; Karahan, Nilay; Murray, Andrew W.; Hallatschek, Oskar; Nelson, David R.

2012-04-01

Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction-diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction-diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays.

Ethylene induced shikonin biosynthesis in shoot culture of Lithospermum erythrorhizon.

PubMed

Touno, Kaori; Tamaoka, Jin; Ohashi, Yuko; Shimomura, Koichiro

2005-02-01

Lithospermum erythrorhizon shoots, cultured on phytohormone-free Murashige and Skoog solid medium, produced shikonin derivatives, whereas shoots cultured in well-ventilated petri dishes, produced small amount. Analysis by gas chromatography revealed the presence of ethylene in non-ventilated petri dishes where the shoots, producing shikonin derivatives, were cultured. Therefore, the possible involvement of ethylene in shikonin biosynthesis of shoot cultures was investigated. Treatment of ethylene or the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, resulted in increasing shikonin derivatives contents in cultured shoots. Silver ion, an ethylene-response inhibitor, or aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, decreased production of shikonin derivatives in cultured shoots. Our results indicate that ethylene is one of the regulatory elements of shikonin biosynthesis in L. erythrorhizon shoot culture.

Effects of diesel and kerosene on germination and growth of coastal wetland plant species.

PubMed

Kim, Kee Dae

2014-11-01

This study aims to investigate effects of diesel and kerosene on seed germination and seedling growth among coastal wetland plants to select species that can be used for the restoration and revegetation of oil-polluted habitats. Tests on 51 species were performed in Petri dishes containing 0 %, 6 %, 12 %, and 18 % diesel, 20 %, 40 %, and 60 % kerosene; each treatment combination was replicated five times with 20 seeds in each Petri dish. All dishes were held in a growth chamber with 20°C day of 12 h/15°C night of 12 h in 80 % humidity for 20 days for calculating the germination percentage, seedling weight, and seedling vitality. The germination percentage of Rumex stenophyllus decreased significantly in diesel and kerosene treatments. The weights of seedlings treated with diesel and kerosene either increased or decreased in comparison with controls depending on the species. Vitality percentage values were high for seedlings of Chenopodium ficifolium. Thus, herbaceous plant responses to oil treatments are species-specific.

Natural Selection in a Petri Dish.

ERIC Educational Resources Information Center

McCarty, Robbie V.; Marek, Edmund A.

1997-01-01

Presents an activity to teach natural selection that involves students in a microbiological investigation. Students discover that a change in environmental conditions tests a species' range of adaptations. (DDR)

Hollow-Fiber Membrane Chamber as a Device for In Situ Environmental Cultivation▿

PubMed Central

Aoi, Yoshiteru; Kinoshita, Tomoyuki; Hata, Toru; Ohta, Hiroaki; Obokata, Haruko; Tsuneda, Satoshi

2009-01-01

A hollow-fiber membrane chamber (HFMC) was developed as an in situ cultivation device for environmental microorganisms. The HFMC system consists of 48 to 96 pieces of porous hollow-fiber membrane connected with injectors. The system allows rapid exchange of chemical compounds, thereby simulating a natural environment. Comparative analysis through the cultivation of three types of environmental samples was performed using this newly designed device and a conventional agar-based petri dish. The results show that the ratios of novel phylotypes in isolates, species-level diversities, and cultivabilities in HFMC-based cultivation are higher than those in an agar-based petri dish for all three samples, suggesting that the new in situ cultivation device is effective for cultivation of various environmental microorganisms. PMID:19329655

Polymeric Microelectronics.

DTIC Science & Technology

1981-06-01

Swelling Procedure For Crosslinked Gel 2A.1 Materials: Spectral grade hexane Petri dish with glass plate cover Planchette Balance Vacuum oven 2A.2...Uncrosslinked Material) To determine the amount of uncrosslinked material decant the dupernatant hexane into a weighed planchette . Wash the gel and...swelling flask or dish with hexane again and pour into planchette . Place the planchette and its contents into a vacuum oven at 350C until the contents

Relative toxicity and residual activity of insecticides used in blueberry pest management: mortality of natural enemies.

PubMed

Roubos, Craig R; Rodriguez-Saona, Cesar; Holdcraft, Robert; Mason, Keith S; Isaacs, Rufus

2014-02-01

A series of bioassays were conducted to determine the relative toxicities and residual activities of insecticides labeled for use in blueberry (Vaccinium corymbosum L.) on natural enemies, to identify products with low toxicity or short duration effects on biological control agents. In total, 14 insecticides were evaluated using treated petri dishes and four commercially available natural enemies (Aphidius colemani Viereck, Orius insidiosus [Say], Chrysoperla rufilabris [Burmeister], and Hippodamia convergens [Guérin-Menéville]). Dishes were aged under greenhouse conditions for 0, 3, 7, or 14 d before introducing insects to test residual activity. Acute effects (combined mortality and knockdown) varied by insecticide, residue age, and natural enemy species. Broad-spectrum insecticides caused high mortality to all biocontrol agents, whereas products approved for use in organic agriculture had little effect. The reduced-risk insecticide acetamiprid consistently caused significant acute effects, even after aging for 14 d. Methoxyfenozide, novaluron, and chlorantraniliprole, which also are classified as reduced-risk insecticides, had low toxicity, and along with the organic products could be compatible with biological control. This study provides information to guide blueberry growers in their selection of insecticides. Further research will be needed to determine whether adoption of a pest management program based on the use of more selective insecticides will result in higher levels of biological control in blueberry.

Rapid fibroblast activation in mammalian cells induced by silicon nanowire arrays

NASA Astrophysics Data System (ADS)

Ha, Qing; Yang, Gao; Ao, Zhuo; Han, Dong; Niu, Fenglan; Wang, Shutao

2014-06-01

Activated tumor-associated fibroblasts (TAFs) with abundant fibroblast activation protein (FAP) expression attract tremendous attention in tumor progression studies. In this work, we report a rapid 24 h FAP activation method for fibroblasts using silicon nanowires (SiNWs) as culture substrates instead of growth factors or chemokines. In contrast with cells cultured on flat silicon which rarely express FAP, SiNW cultivated cells exhibit FAP levels similar to those found in cancerous tissue. We demonstrated that activated cells grown on SiNWs maintain their viability and proliferation in a time-dependent manner. Moreover, environmental scanning electron microscopy (ESEM) and focused ion beam and scanning electron microscopy (FIB-SEM) analysis clearly revealed that activated cells on SiNWs adapt to the structure of their substrates by filling inter-wire cavities via filopodia in contrast to cells cultured on flat silicon which spread freely. We further illustrated that the expression of FAP was rarely detected in activated cells after being re-cultured in Petri dishes, suggesting that the unique structure of SiNWs may have a certain influence on FAP activation.Activated tumor-associated fibroblasts (TAFs) with abundant fibroblast activation protein (FAP) expression attract tremendous attention in tumor progression studies. In this work, we report a rapid 24 h FAP activation method for fibroblasts using silicon nanowires (SiNWs) as culture substrates instead of growth factors or chemokines. In contrast with cells cultured on flat silicon which rarely express FAP, SiNW cultivated cells exhibit FAP levels similar to those found in cancerous tissue. We demonstrated that activated cells grown on SiNWs maintain their viability and proliferation in a time-dependent manner. Moreover, environmental scanning electron microscopy (ESEM) and focused ion beam and scanning electron microscopy (FIB-SEM) analysis clearly revealed that activated cells on SiNWs adapt to the structure of their substrates by filling inter-wire cavities via filopodia in contrast to cells cultured on flat silicon which spread freely. We further illustrated that the expression of FAP was rarely detected in activated cells after being re-cultured in Petri dishes, suggesting that the unique structure of SiNWs may have a certain influence on FAP activation. Electronic supplementary information (ESI) available: (1) ESEM cross-sectional view images of the flat silicon and SiNW substrates. (2) Bright field morphology images of fibroblasts cultured in Petri dishes. (3) FIB/SEM 52° tilt images of fibroblasts cultured on SiNW 2 and SiNW 3. (4) Immunofluorescence images of FAP expression in fibroblasts re-cultured in Petri dishes after detachment from flat silicon and a series of SiNW substrates. (5) ESEM images of cells re-cultured in Petri dishes after detachment from each group. See DOI: 10.1039/c4nr01415d

Baseline susceptibility of Planococcus ficus (Hemiptera: Pseudococcidae) from California to select insecticides.

PubMed

Prabhaker, Nilima; Gispert, Carmen; Castle, Steven J

2012-08-01

Between 2006 and 2008, 20 populations of Planococcus ficus (Signoret), from Coachella and San Joaquin Valleys of California were measured in the laboratory for susceptibility to buprofezin, chlorpyrifos, dimethoate, methomyl, and imidacloprid. Toxicity was assessed using a petri dish bioassay technique for contact insecticides and by a systemic uptake technique for imidacloprid. Mixed life stages were tested for susceptibility to all insecticides except for buprofezin, which was measured against early and late instars (first, second, and third). Dose-response regression lines from the mortality data established LC50 and LC99 values by both techniques. Responses of populations from the two geographical locations to all five insecticides varied, in some cases significantly. Variations in susceptibility to each insecticide among sample sites showed a sevenfold difference for buprofezin, 11-fold to chlorpyrifos, ninefold to dimethoate, 24-fold to methomyl, and 8.5-fold to imidacloprid. In spite of susceptibility differences between populations, baseline toxicity data revealed that all five insecticides were quite effective based on low LC50s. Chlorpyrifos was the most toxic compound to Planococcus ficus populations as shown by lowest LC50s. Buprofezin was toxic to all immature stages but was more potent to first instars. The highest LC99 estimated by probit analysis of the bioassay data of all 20 populations for each compound was selected as a candidate discriminating dose for use in future resistance monitoring efforts. Establishment of baseline data and development of resistance monitoring tools such as bioassay methods and discriminating doses are essential elements of a sustainable management program for Planococcus ficus.

The Presence of Flour Affects the Efficacy of Aerosolized Insecticides used to Treat the Red Flour Beetle, Tribolium castaneum

PubMed Central

Toews, Michael D.; Campbell, James F.; Arthur, Franklin H.

2010-01-01

Experiments were conducted in tightly sealed pilot scale warehouses to assess the efficacy of common aerosolized insecticides on all life stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) when exposed in dishes containing 0 to 2 g of wheat flour either under pallets or out in the open. Petri dishes containing 0, 0.1, 1, or 2 g of flour were prepared with 25 eggs, 3rd instars, pupae, or adults and then immediately treated with aerosolized solvent, Pyrethrins, or esfenvalerate. Twenty-four h after insecticide exposure, the dishes were brought to the laboratory and placed in a growth chamber and held for a 3 day moribund (knockdown) assessment and a 21 day mortality assessment. Mortality in untreated controls was generally less than 10%, with the exception of the 21 day counts of adults and eggs. Solvent-treated replications followed similar trends, except that additional mortality was observed in exposed larvae and pupae. In the insecticide-treated dishes, mortality of T. castaneum provisioned with flour generally showed a linear decrease with increasing flour deposits. Regardless of life stage, mortality did not exceed 60% when individuals were exposed in petri dishes containing 2 g of flour. Exposure location also made a significant difference in observed mortality. While mortality never exceeded 75% in dishes positioned under pallets, there was never less than 80% mortality in dishes exposed in the open. Although there was a perceptible increase in mortality with esfenvalerate compared to Pyrethrins, these differences were considerably less than the variation observed among flour deposits. The study suggests that sanitation and preparation prior to aerosol insecticide treatments were more important than choice of a particular insecticide. PMID:21268701

Pathogenicity of Steinernema carpocapsae and Steinernema glaseri (Nematoda:Steinernematidae) to Ixodes Scapularis (Acari:Ixodidae)

USGS Publications Warehouse

Zhioua, E.; LeBrun, R.A.; Ginsberg, H.S.; Aeschliman, A.

1995-01-01

The entomopathogenic nematodes Steinernema carpocapsae (Weiser) and S. glaseri (Steiner) are pathogenic to engorged adult, blacklegged ticks, Ixodes scapularis (Say), but not to unfed females, engorged nymphs, or engorged larvae. Nematodes apparently enter the tick through the genital pore, thus precluding infection of immature ticks. The timing of tick mortality, and overall mortality after 17 d, did not differ between infections by S. carpocapsae and S. glaseri. These nematodes typically do not complete their life cycles or produce infective juveniles in I. scapularis. However, both species successfully produced infective juveniles when the tick body was slit before nematode infection. Mortality of engorged I. scapularis females infected by S. carpocapsae was greater than uninfected controls, but did not vary significantly with nematode concentration (50-3,000 infective juveniles per 5-cm-diameter petri dish). The LC50 was 347.8 infective juveniles per petri dish (5 ticks per dish). Hatched egg masses of infected ticks weighed less than those of uninfected controls. Mortality of infected ticks was greatest between 20 and 30?C, and was lower at 15?C.

Highly effective fungal inactivation in He+O2 atmospheric-pressure nonequilibrium plasmas

NASA Astrophysics Data System (ADS)

Xiong, Z.; Lu, X. P.; Feng, A.; Pan, Y.; Ostrikov, K.

2010-12-01

Highly effective (more than 99.9%) inactivation of a pathogenic fungus Candida albicans commonly found in oral, respiratory, digestive, and reproduction systems of a human body using atmospheric-pressure plasma jets sustained in He+O2 gas mixtures is reported. The inactivation is demonstrated in two fungal culture configurations with open (Petri dish without a cover) and restricted access to the atmosphere (Petri dish with a cover) under specific experimental conditions. It is shown that the fungal inactivation is remarkably more effective in the second configuration. This observation is supported by the scanning and transmission electron microscopy of the fungi before and after the plasma treatment. The inactivation mechanism explains the experimental observations under different experimental conditions and is consistent with the reports by other authors. The results are promising for the development of advanced health care applications.

Ovicidal activity of different concentrations of Pochonia chlamydosporia chlamydospores on Taenia taeniaeformis eggs.

PubMed

Braga, F R; Silva, A R; Carvalho, R O; Araújo, J V; Pinto, P S A

2011-03-01

Three concentrations of chlamydospores of the nematophagous fungus Pochonia chlamydosporia (1000, 10,000 and 20,000 per Petri dish) were evaluated in vitro on Taenia taeniaeformis eggs. Chlamydospores at each concentration were cultured in two different media: 2% water-agar (2%WA) and 2% corn-meal-agar (2%CMA). Taenia taeniaeformis eggs were plated in each chlamydospore concentration in 2%WA and 2%CMA (treated groups) and without fungus (control group). Eggs were removed from each Petri dish at intervals of 7, 14 and 21 days and classified according to ovicidal activity (type 1, type 2 and type 3 effects). Plates containing 2%CMA showed the highest percentages for type 3 effect (81.3%) on the 21st day of observation. A difference (P < 0.01) between the media 2%WA and 2%CMA for type 1 effect was observed only at a concentration of 1000 chlamydospores on the 7th day. There were differences (P < 0.01) between 2%WA and 2%CMA on the 14th and 21st days, at the concentration of 20,000 chlamydospores, for type 1 and type 3 effects. Regression curves for type 3 effect in 2%WA and 2%CMA at the tested concentrations showed higher ovicidal activity with increasing chlamydospore concentrations. Results indicate that, at concentrations of 1000, 10,000 and 20,000 per Petri dish, chlamydospores of P. chlamydosporia effectively destroyed T. taeniaeformis eggs and can be considered a potential biological control agent for this cestode.

Reusable anaerobic system for microbiological studies - A concept

NASA Technical Reports Server (NTRS)

Murawczyk, C.

1971-01-01

Simple, low cost system consists of semirigid incubation chamber with clear Teflon window, airtight zipper and internal compartments for petri dishes or microbial plates. Device interests schools, medical laboratories, and manufacturers of biological and pharmaceutical supplies.

Dispersal of Beauveria bassiana by the activity of nettle insects.

PubMed

Meyling, Nicolai V; Pell, Judith K; Eilenberg, Jørgen

2006-10-01

Recent studies have shown that the entomopathogenic fungus Beauveria bassiana occurs naturally on the phylloplanes of several plants, including nettles. Insects could, by their activity, be contributing to this inoculum by dispersing it from other sites. The potential of nettle aphids Microlophium carnosum and their predator Anthocoris nemorum to disperse conidia of B. bassiana from soil to nettles and from sporulating cadavers in the nettle canopy was investigated in laboratory experiments. In petri dish assays, aphids showed potential to distribute B. bassiana from soil to nettle leaves. Predators dispersed inoculum from both soil and cadavers to nettle leaves in petri dishes. In microcosms, aphids did not disperse B. bassiana from the soil or from cadavers confined in the canopy, but A. nemorum were able to transfer inoculum from soil into the nettle canopy and to distribute conidia from cryptic cadavers. In some instances, infections were initiated in aphids and predators as a consequence of dispersal.

Highly effective fungal inactivation in He+O{sub 2} atmospheric-pressure nonequilibrium plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Z.; Lu, X. P.; Pan, Y.

2010-12-15

Highly effective (more than 99.9%) inactivation of a pathogenic fungus Candida albicans commonly found in oral, respiratory, digestive, and reproduction systems of a human body using atmospheric-pressure plasma jets sustained in He+O{sub 2} gas mixtures is reported. The inactivation is demonstrated in two fungal culture configurations with open (Petri dish without a cover) and restricted access to the atmosphere (Petri dish with a cover) under specific experimental conditions. It is shown that the fungal inactivation is remarkably more effective in the second configuration. This observation is supported by the scanning and transmission electron microscopy of the fungi before and aftermore » the plasma treatment. The inactivation mechanism explains the experimental observations under different experimental conditions and is consistent with the reports by other authors. The results are promising for the development of advanced health care applications.« less

Evaluation of efficacy of 18 strains of entomopathogenic nematodes (Rhabditida) against Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) under laboratory conditions.

PubMed

Barbosa Negrisoli, Carla Ruth de Carvalho; Negrisoli Júnior, Aldomario Santo; Botton, Marcos; Garcia, Mauro Silveira; Bernardi, Daniel

2013-07-01

Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25±1°C, UR 60±10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, Steinernema feltiae, Steinernema riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (Steinernema carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was H. bacteriophora RS33 (from 69.0% to 92.2% of mortality), native of Rio Grande do Sul. Copyright © 2013 Elsevier Inc. All rights reserved.

Centripetal Force on an Overhead Projector.

ERIC Educational Resources Information Center

Rheam, Harry

1995-01-01

Describes two simple demonstrations of an object moving in a straight line tangent to the circle if centripetal force is removed. Demonstrations use a pie plate and petri dish with ball bearings to illustrate the phenomena on an overhead projector. (LZ)

Fate of Bacterial and Viral Bio-Warfare Agents in Disinfected Waters

DTIC Science & Technology

2010-10-01

600 nm; approximately 4 h). An aliquot of 0.4 mL bacterial culture is spread onto the surface of Sporulation Media A Medium (SMA) and incubated at...dishes containing Sporulation Medium Sterile distilled water at 4 °C 70% EtOH Crystal violet Stain 1.2 Sporulation media A: Nutrient broth 8g/L...phase (approximately 4 h). 2.2 Seeding the Sporulation Plates 1. Label 150 mm Petri dishes of SM A Medium. 2. Inoculate, by aseptically spreading

Comparative Toxicities of Newer and Conventional Insecticides: Against Four Generalist Predator Species.

PubMed

Prabhaker, Nilima; Naranjo, Steven; Perring, Thomas; Castle, Steven

2017-12-05

Generalist insect predators play an essential role in regulating the populations of Bemisia tabaci and other pests in agricultural systems, but may be affected negatively by insecticides applied for pest management. Evaluation of insecticide compatibility with specific predator species can provide a basis for making treatment decisions with the aim of conserving natural enemies. Eleven insecticides representing six modes of action groups were evaluated for toxicity against four predator species and at different developmental stages. Full-concentration series bioassays were conducted on laboratory-reared or insectary-supplied predators using Petri dish and systemic uptake bioassay techniques. Highest toxicities were observed with imidacloprid and clothianidin against first and second instar nymphs of Geocoris punctipes (Say) (Hemiptera: Geocoridae). Later instar nymphs were less susceptible to neonicotinoid treatments based on higher LC50s observed with imidacloprid, thiamethoxam, and dinotefuran against third or fourth instar nymphs. The pyrethroid insecticide bifenthrin was highly toxic against adults of G. punctipes and Orius insidiosus (Say) (Hemiptera: Anthocoridae). Standard concentration/mortality evaluation of nonacute toxicity insecticides, including buprofezin, pyriproxyfen, spirotetramat, and spiromesifen, was inconclusive in terms of generating probit statistics. However, low mortality levels of insects exposed for up to 120 h suggested minimal lethality with the exception of pyriproxyfen that was mildly toxic to Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae). Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Why cage a tree? Use of whole-tree enclosures to assess introduced predators of hemlock woolly adelgid, Adelges tsugae

Treesearch

Jerome F. Grant; James Rusty Rhea; Paris Lambdin; Greg Wiggins; Abdul Hakeem

2009-01-01

While commonly used approaches (petri dishes, small arenas, growth chambers, greenhouse studies, sleeve cages, etc.) for evaluation of natural enemies provide important information, does the small size of these arenas limit their...

Overhead Projector Demonstrations.

ERIC Educational Resources Information Center

Kolb, Doris, Ed.

1988-01-01

Provides two demonstrations: (1) electrolyte migration of ions using colored ions which cross a strip of gelatin allowing for noticeable migration; and (2) photochemical reduction of Fe+3 by the citrate ion. Points out both reactions can be done in a Petri dish using common lab materials. (MVL)

Vector potential of houseflies (Musca domestica) for Helicobacter pylori.

PubMed

Grübel, P; Hoffman, J S; Chong, F K; Burstein, N A; Mepani, C; Cave, D R

1997-06-01

The mode of transmission of Helicobacter pylori is unknown. Since viable bacteria have been shown to be excreted in feces from infected individuals and houseflies habitually develop and feed on excrement, we hypothesized that flies ingest and harbor H. pylori and, in turn, contaminate the human environment. This study examined the possible vector potential of houseflies (Musca domestica) for H. pylori. Caged houseflies were exposed to freshly grown H. pylori on agar plates. After a 6-h feeding period, the plates were removed and were replaced with sterile petri dishes containing a droplet of sterile brucella broth. At regular intervals, small numbers of houseflies were removed for microbiological and histological analysis, and the petri dishes were replaced with fresh sterile plates with fresh drops of brucella broth. The flies' bodies, the flies' dissected alimentary tracts, and excreta on the petri dishes were cultured for H. pylori, whose identity was confirmed by the urease, catalase, and oxidase reactions and Gram staining. In contrast to control flies, viable H. pylori could be isolated from external surfaces for up to 12 h and from gut and excreta for as long as 30 h after the initial feeding period. After 30 h other gram-negative bacteria overgrew the cultures of samples from all locations tested, rendering the selective culture of H. pylori colonies impossible. Histological analysis revealed Helicobacter-like organisms in the gut lumen and attached to intestinal epithelial cells. We conclude that houseflies can harbor viable H. pylori on their bodies and in their intestinal tracts. They are also able to disseminate viable H. pylori in excreta, and they may therefore present a significant reservoir and be a vector in the transmission of H. pylori.

Vector potential of houseflies (Musca domestica) for Helicobacter pylori.

PubMed Central

Grübel, P; Hoffman, J S; Chong, F K; Burstein, N A; Mepani, C; Cave, D R

1997-01-01

The mode of transmission of Helicobacter pylori is unknown. Since viable bacteria have been shown to be excreted in feces from infected individuals and houseflies habitually develop and feed on excrement, we hypothesized that flies ingest and harbor H. pylori and, in turn, contaminate the human environment. This study examined the possible vector potential of houseflies (Musca domestica) for H. pylori. Caged houseflies were exposed to freshly grown H. pylori on agar plates. After a 6-h feeding period, the plates were removed and were replaced with sterile petri dishes containing a droplet of sterile brucella broth. At regular intervals, small numbers of houseflies were removed for microbiological and histological analysis, and the petri dishes were replaced with fresh sterile plates with fresh drops of brucella broth. The flies' bodies, the flies' dissected alimentary tracts, and excreta on the petri dishes were cultured for H. pylori, whose identity was confirmed by the urease, catalase, and oxidase reactions and Gram staining. In contrast to control flies, viable H. pylori could be isolated from external surfaces for up to 12 h and from gut and excreta for as long as 30 h after the initial feeding period. After 30 h other gram-negative bacteria overgrew the cultures of samples from all locations tested, rendering the selective culture of H. pylori colonies impossible. Histological analysis revealed Helicobacter-like organisms in the gut lumen and attached to intestinal epithelial cells. We conclude that houseflies can harbor viable H. pylori on their bodies and in their intestinal tracts. They are also able to disseminate viable H. pylori in excreta, and they may therefore present a significant reservoir and be a vector in the transmission of H. pylori. PMID:9163433

Interwoven four-compartment capillary membrane technology for three-dimensional perfusion with decentralized mass exchange to scale up embryonic stem cell culture.

PubMed

Gerlach, Jörg C; Lübberstedt, Marc; Edsbagge, Josefina; Ring, Alexander; Hout, Mariah; Baun, Matt; Rossberg, Ingrid; Knöspel, Fanny; Peters, Grant; Eckert, Klaus; Wulf-Goldenberg, Annika; Björquist, Petter; Stachelscheid, Harald; Urbaniak, Thomas; Schatten, Gerald; Miki, Toshio; Schmelzer, Eva; Zeilinger, Katrin

2010-01-01

We describe hollow fiber-based three-dimensional (3D) dynamic perfusion bioreactor technology for embryonic stem cells (ESC) which is scalable for laboratory and potentially clinical translation applications. We added 2 more compartments to the typical 2-compartment devices, namely an additional media capillary compartment for countercurrent 'arteriovenous' flow and an oxygenation capillary compartment. Each capillary membrane compartment can be perfused independently. Interweaving the 3 capillary systems to form repetitive units allows bioreactor scalability by multiplying the capillary units and provides decentralized media perfusion while enhancing mass exchange and reducing gradient distances from decimeters to more physiologic lengths of <1 mm. The exterior of the resulting membrane network, the cell compartment, is used as a physically active scaffold for cell aggregation; adjusting intercapillary distances enables control of the size of cell aggregates. To demonstrate the technology, mouse ESC (mESC) were cultured in 8- or 800-ml cell compartment bioreactors. We were able to confirm the hypothesis that this bioreactor enables mESC expansion qualitatively comparable to that obtained with Petri dishes, but on a larger scale. To test this, we compared the growth of 129/SVEV mESC in static two-dimensional Petri dishes with that in 3D perfusion bioreactors. We then tested the feasibility of scaling up the culture. In an 800-ml prototype, we cultured approximately 5 x 10(9) cells, replacing up to 800 conventional 100-mm Petri dishes. Teratoma formation studies in mice confirmed protein expression and gene expression results with regard to maintaining 'stemness' markers during cell expansion. Copyright 2010 S. Karger AG, Basel.

The Effect of Various Oral Hygiene Products on Bacterial Growth

NASA Astrophysics Data System (ADS)

Viswanath, S.; Aggrawal, A.; Vazirani, S.

2017-12-01

In this experiment, we tested the antimicrobial effectiveness of six different oral hygiene products. We used three natural cleansing products (coconut oil, sea salt, and baking soda), as well as three synthetic products, which were the Colgate toothpaste varieties of sensitivity, cavity protection, and whitening. We mixed water with each of the products to create a paste that could be uniformly applied to the surface of a disc. We then dipped the discs into the solutions and placed them in petri dishes that were pre-treated with bacterial cells. After 72 hours, we measured the area around the disc that was bacteria-free, which is known as the zone of inhibition. This experiment was repeated twice, with one petri dish per product for each trial, and two different types of agar. We were surprised to discover that almost all the products had no zone of inhibition, with bacteria growing throughout the petri dish, and to the disc. The only cleaning product that showed a significant antibacterial result was the Colgate sensitivity toothpaste. During the two trials, the sensitivity toothpaste had a zone of inhibition of 14.8 cm2 and 8.7 cm2, respectively. Coconut oil was the only other product to have a measurable zone of inhibition with an area of 0.3 cm2. We concluded that only the sensitivity toothpaste was effective in killing bacteria, perhaps due to its different hygienic goal of protecting the tooth's nerves. This toothpaste contains ingredients called potassium nitrate and strontium chloride, which blocks tubules in the dentin, the hard, bony tissue beneath the enamel. Sensitivity toothpaste strengthens the tooth, by blocking decaying substances such as oral bacteria (Knights, 2014).

Effective allergen avoidance for reducing exposure to house dust mite allergens and improving disease management in adult atopic asthmatics.

PubMed

Tsurikisawa, Naomi; Saito, Akemi; Oshikata, Chiyako; Yasueda, Hiroshi; Akiyama, Kazuo

2016-10-01

We investigated the best strategy for adult asthmatics to avoid exposure to Dermatophagoides group (Der-1) allergens. Adult atopic asthmatics (n = 111) followed a 32-item checklist for avoiding Der-1 allergen exposure. Twenty-five patients were excluded through incomplete sampling; 50 remaining patients encased their pillows/futons/mattresses in microfine-fiber covers, 13 used vacuum cleaners with dust-mite-collection nozzles, and 23 acted as non-intervention controls. During August-October 2010 and August-October 2011, dust samples were collected in Petri dishes placed in bedrooms for 2 weeks and from mattresses/futons by using adhesive tape on one morning. A Der-1 level decrease was defined as a mean 2011 Der-1 level of <1 as a ratio of the 2010 level on tape or Petri dish samples. We analyzed the associations between Der-1 level change (by ELISA) and % weekly variability in peak expiratory flow (PEF) or fraction of exhaled nitric oxide (FeNO) after intervention. Der-1 levels decreased significantly in the covers group but not the vacuuming group. FeNO levels and PEF variability were unchanged in both groups. In patients whose Petri dish or tape samples showed decreased Der-1 levels, the % PEF variability was lower in 2011 than in 2010, but FeNO levels were unchanged. Three interventions (vacuuming all family members' mattress/futon surfaces at least weekly or after exposure of the futons to sunlight, and floor wiping before vacuuming), plus using covers, were the most effective management strategy in reducing Der-1 levels. This environmental and bedding maintenance program may help manage adult atopic asthma.

Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination.

PubMed

Jiang, Jinglong; Su, Miao; Wang, Liyan; Jiao, Chengjin; Sun, Zhengxi; Cheng, Wei; Li, Fengmin; Wang, Chongying

2012-04-01

During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L.) grew perpendicular to the bottom of the Petri dish, due to gravitropism. However, when germinated in exogenous hydrogen peroxide (H(2)O(2)), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H(2)O(2) was applied prior to the emergence of the primary root. H(2)O(2) failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H(2)O(2) concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H(2)O(2), but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H(2)O(2) production. Exogenous H(2)O(2) treatment caused both an increase in the activities of H(2)O(2)-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H(2)O(2) levels and root vitality. Although grass pea seeds absorbed exogenous H(2)O(2) during seed germination, DAB staining of paraffin sections revealed that exogenous H(2)O(2) only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H(2)O(2) could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Post-accident recovery of hardware and moss cultures from STS-107

NASA Astrophysics Data System (ADS)

Kern, V. D.; Reed, D. W.; Sack, F. D.

In a follow-up investigation to our STS-87 moss experiment, 99 cultures of the moss Ceratodon purpureus were launched on January 16, 2003, and incubated under microgravity conditions for up to 15 days onboard the orbiter Columbia during the STS-107 mission. Following a flawless performance during the on-orbit experiment phase, cultures were chemically fixed in space by the crew at pre-determined intervals. After the accidental break up of Columbia during descent on February 1, 2003, it was assumed that no results would be available since all cultures and data were to be retrieved for analysis post-landing. However, during the subsequent months seven out of eight BRIC (Biological Research in Canisters)-LED containers were recovered on the ground by searchers in Eastern Texas. Each canister housed six polycarbonate Petri Dish Fixation Units (PDFUs) containing petri dishes with 1 or 3 moss cultures each. When these canisters were opened in late April at Kennedy Space Center, 86 out of 87 moss cultures were recovered. Many but not all cultures were severely fragmented and it was impossible to discern growth patterns. However, thousands of well-fixed moss apical cells were found and documented by microscopy. Data retrieved from an internal temperature logger indicated that the canisters experienced intense but transient heat shortly after Columbia broke apart. Some PDFU polycarbonate had fused to the aluminum canister wall. Interior temperatures were sufficient to melt the agarose substrate (˜ 88C), but none of the 41 petri dishes was heat damaged. Initial results from the examination of culture and cell morphology will be presented. (Supported by NASA: NAG10-0179.)

Simultaneous recording of electrical activity and the underlying ionic currents in NG108-15 cells cultured on gold substrate.

PubMed

Acosta-García, Ma Cristina; Morales-Reyes, Israel; Jiménez-Anguiano, Anabel; Batina, Nikola; Castellanos, N P; Godínez-Fernández, R

2018-02-01

This paper shows the simultaneous recording of electrical activity and the underlying ionic currents by using a gold substrate to culture NG108-15 cells. Cells grown on two different substrates (plastic Petri dishes and gold substrates) were characterized quantitatively through scanning electron microscopy (SEM) as well as qualitatively by optical and atomic force microscopy (AFM). No significant differences were observed between the surface area of cells cultured on gold substrates and Petri dishes, as indicated by measurements performed on SEM images. We also evaluated the electrophysiological compatibility of the cells through standard patch-clamp experiments by analyzing features such as the resting potential, membrane resistance, ionic currents, etc. Cells grown on both substrates showed no significant differences in their dependency on voltage, as well as in the magnitude of the Na+ and K+ current density; however, cells cultured on the gold substrate showed a lower membrane capacitance when compared to those grown on Petri dishes. By using two separate patch-clamp amplifiers, we were able to record the membrane current with the conventional patch-clamp technique and through the gold substrate simultaneously. Furthermore, the proposed technique allowed us to obtain simultaneous recordings of the electrical activity (such as action potentials firing) and the underlying membrane ionic currents. The excellent conductivity of gold makes it possible to overcome important difficulties found in conventional electrophysiological experiments such as those presented by the resistance of the electrolytic bath solution. We conclude that the technique here presented constitutes a solution to the problem of the simultaneous recording of electrical activity and the underlying ionic currents, which for decades, had been solved only partially.

Rhinitis, Ocular, Throat and Dermal Symptoms, Headache and Tiredness among Students in Schools from Johor Bahru, Malaysia: Associations with Fungal DNA and Mycotoxins in Classroom Dust

PubMed Central

Norbäck, Dan; Hashim, Jamal Hisham; Cai, Gui-Hong; Hashim, Zailina; Ali, Faridah; Bloom, Erica; Larsson, Lennart

2016-01-01

There are few studies on rhinitis and sick building syndrome (SBS) among students in tropical countries. We studied associations between levels of five fungal DNA sequences, two mycotoxins (sterigmatocystin and verrucarol) and cat allergen (Fel d 1) levels in schools and rhinitis and other weekly SBS symptoms in the students. Fungal DNA was measured by quantitative PCR and cat allergen by ELISA. Pupils (N = 462) from eight randomly selected schools in Johor Bahru, Malaysia participated (96%). Dust samples were collected by cotton swabs and Petri dishes exposed for one week. None of the schools had a mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures and indoor CO2 levels were low (mean 492 ppm; range 380–690 ppm). Weekly nasal symptoms (rhinitis) (18.8%), ocular (11.6%), throat (11.1%), dermal symptoms, headache (20.6%) and tiredness (22.1%) were common. Total fungal DNA in swab samples was associated with rhinitis (p = 0.02), ocular symptoms (p = 0.009) and tiredness (p = 0.001). There were positive associations between Aspergillus versicolor DNA in Petri dish samples, ocular symptoms (p = 0.02) and tiredness (p = 0.001). The level of the mycotoxin verrucarol (produced by Stachybotrys chartarum) in swab samples was positively associated with tiredness (p = 0.04). Streptomyces DNA in swab samples (p = 0.03) and Petri dish samples (p = 0.03) were negatively associated with tiredness. In conclusion, total fungal contamination, measured as total fungal DNA) in the classrooms, Aspergillus versicolor and verrucarol can be risk factors for rhinitis and SBS symptoms among students in the tropical country Malaysia. PMID:26829324

Evaluation of predation of the mite Lasioseius penicilliger (Aracnida: Mesostigmata) on Haemonchus contortus and bacteria-feeding nematodes.

PubMed

Aguilar-Marcelino, L; Quintero-Martínez, M T; Mendoza de Gives, P; López-Arellano, M E; Liébano-Hernández, E; Torres-Hernández, G; González-Camacho, J M; Cid del Prado, I

2014-03-01

Predation by the mite Lasioseius penicilliger was studied on three nematode species, i.e. infective larval stages (L3) of Haemonchus contortus and adults of Panagrellus redivivus and Rhabditis sp. Experiments were carried out in 5.5-cm diameter Petri dishes containing 2% water-agar over a period of 5 days. Batches of up to 1500 third-stage larvae (L3) of H. contortus and 1000 adult nematodes of P. redivivus and Rhabditis sp. were exposed to five mites in separate Petri dishes. Upon contact, each mite used its pedipalp and legs to identify and hold its prey and then used its chelicerae to feed upon the prey. Predation by L. penicilliger was chance dependent but mites became aggregated around any injured/damaged prey, thereby suggesting some form of chemoperception. The rate of predation on the three species of nematodes was high but L3 of H. contortus and adult Rhabditis sp. were preferred.

Nonlinearity in bacterial population dynamics: Proposal for experiments for the observation of abrupt transitions in patches

PubMed Central

Kenkre, V. M.; Kumar, Niraj

2008-01-01

An explicit proposal for experiments leading to abrupt transitions in spatially extended bacterial populations in a Petri dish is presented on the basis of an exact formula obtained through an analytic theory. The theory provides accurately the transition expressions despite the fact that the actual solutions, which involve strong nonlinearity, are inaccessible to it. The analytic expressions are verified through numerical solutions of the relevant nonlinear equation. The experimental setup suggested uses opaque masks in a Petri dish bathed in ultraviolet radiation [Lin A-L, et al. (2004) Biophys J 87:75–80 and Perry N (2005) J R Soc Interface 2:379–387], but is based on the interplay of two distances the bacteria must traverse, one of them favorable and the other adverse. As a result of this interplay feature, the experiments proposed introduce highly enhanced reliability in interpretation of observations and in the potential for extraction of system parameters. PMID:19033185

Modelling of different enzyme productions by solid-state fermentation on several agro-industrial residues.

PubMed

Diaz, Ana Belen; Blandino, Ana; Webb, Colin; Caro, Ildefonso

2016-11-01

A simple kinetic model, with only three fitting parameters, for several enzyme productions in Petri dishes by solid-state fermentation is proposed in this paper, which may be a valuable tool for simulation of this type of processes. Basically, the model is able to predict temporal fungal enzyme production by solid-state fermentation on complex substrates, maximum enzyme activity expected and time at which these maxima are reached. In this work, several fermentations in solid state were performed in Petri dishes, using four filamentous fungi grown on different agro-industrial residues, measuring xylanase, exo-polygalacturonase, cellulose and laccase activities over time. Regression coefficients after fitting experimental data to the proposed model turned out to be quite high in all cases. In fact, these results are very interesting considering, on the one hand, the simplicity of the model and, on the other hand, that enzyme activities correspond to different enzymes, produced by different fungi on different substrates.

Radiofrequency radiation effects on the common bean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomkins, K.; Griggs, L.; Myles, E.L.

Our environment is bombarded daily with thousands of objects we can visually detect. However, invisible to humans are the electromagnetic waves that penetrate our environment. Electromagnetic waves consist of a large spectrum of waves including the harmful gamma rays, x-rays, and ultraviolet rays. The question that has increased tremendously is: can low energy electromagnetic waves become harmful to living organisms? The purpose of this study is to determine the effect of radiofrequency radiation on protein synthesis of the common bean. Phaseolus vulgaris (kidney bean) was surface-sterilized and allowed to germinate on Mushurage and Skoog`s medium for 1 week. Hypocotyls weremore » wounded and placed on media to initiate callus production. Six petri dishes containing 1 g of callus were used in the experiment. Three dishes were exposed to 100kH in a Crawford cell for 24h. The remaining three petri dishes with callus were used as a control. After the exposure period, the protein from callus was extracted and analyzed by one-dimensional gel electrophoresis. The results show that hypocotyl growth was not different between control and experimental groups after 24 h. The result of one-dimensional gel electrophoresis did not show observable differences in protein synthesized by the control and experimental groups. Analysis of protein synthesis is still ongoing.« less

Attractants from Bartlett pear for codling moth, Cydia pomonella (L.), larvae

NASA Astrophysics Data System (ADS)

Knight, Alan L.; Light, Douglas M.

2001-08-01

The alkyl ethyl and methyl esters of (2 E,4 Z)-2,4-decadienoic acid found in head-space samples of ripe Bartlett pear ( Pyrus communis L.) stimulated a response from neonate larvae of the codling moth (CM), Cydia pomonella (L.), in both static-air Petri-plate and in upwind Y-tube and straight-tube olfactometer bioassays. In comparison with the known CM neonate attractant, ( E,E)-α-farnesene, ethyl (2 E,4 Z)-2,4-decadienoate was attractive at 10-fold and 1,000-fold lower threshold dosages in the Petri-plate and in the Y-tube bioassays, respectively. Methyl (2 E,4 Z)-2,4-decadienoate was attractive to CM neonates in these bioassays at much higher doses than ethyl (2 E,4 Z)-2,4-decadienoate. Other principal head-space volatiles from ripe pear fruit and pear leaves, including butyl acetate, hexyl acetate, ( Z)-3-hexenyl acetate, and ( E)-β-ocimene, were not attractive to CM neonates. The potential uses of these pear kairomones for monitoring and control of CM in walnuts and apple are discussed.

Essential oils as fumigants for bed bugs (Hemiptera: Cimicidae)

USDA-ARS?s Scientific Manuscript database

In Petri dish assays, fumigation of a pyrethroid-susceptible strain of bed bugs Cimex lectularius L. (Hemiptera: Cimicidae) with various essential oils resulted in mortality that approached or equaled 100%, after 5 days. However, when bed bugs were exposed to the same essential oils in sealed, comme...

ACTION OF 50 HZ MAGNETIC FIELDS ON NEURITE OUTGROWTH IN PHEOCHROMOCYTOMA CELLS

EPA Science Inventory

This study tests the capacity of 50-Hz magnetic and electric fields to stimulate neurite outgrowth in PC-12D cells, a cell line which originated from a pheochromocytoma in rat adrenal medulla. he cells were plated on collagen-coated plastic petri dishes and exposed to sinusoidal ...

Recommendations for treated-area choice assays with termites (Isoptera)

Treesearch

Chris J. Peterson; Patrick D. Gerard; Janice Ems-Wilson

2005-01-01

The repellency of catnip (Nepeta cataria) essential oil was evaluated in a treated-area choice assay with subterranean termites (Reticulitermes spp.). It appeared that fewer R. virginicus were found on the treated portion of a petri dish within a period of about 7d; R. flavipes was not...

Surface-Acoustic-Wave (SAW)-Driven Device for Dynamic Cell Cultures.

PubMed

Greco, Gina; Agostini, Matteo; Tonazzini, Ilaria; Sallemi, Damiano; Barone, Stefano; Cecchini, Marco

2018-06-19

In the last few decades, new types of cell cultures have been introduced to provide better cell survival and development, with micro- and nanoenvironmental physicochemical conditions aimed at mimicking those present in vivo. However, despite the efforts made, the systems available to date are often difficult to replicate and use. Here, an easy-to-use surface-acoustic-wave (SAW)-based platform is presented for realizing dynamic cell cultures that is compatible with standard optical microscopes, incubators, and cell-culture dishes. The SAW chip is coupled to a standard Petri dish via a polydimethylsiloxane (PDMS) disc and consists of a lithium niobate (LN) substrate on which gold interdigital transducers (IDTs) are patterned to generate the SAWs and induce acoustic streaming in the dish. SAW excitation is verified and characterized by laser Doppler vibrometry, and the fluid dynamics is studied by microparticle image velocimetry (μPIV). Heating is measured by an infrared (IR) thermal camera. We finally tested this device with the U-937 monocyte cell line for viability and proliferation and cell-morphological analysis. The data demonstrate that it is possible to induce significant fluid recirculation within the Petri dish while maintaining negligible heating. Remarkably, cell proliferation in this condition was enhanced by 36 ± 12% with respect to those of standard static cultures. Finally, we show that cell death does not increase and that cell morphology is not altered in the presence of SAWs. This device is the first demonstration that SAW-induced streaming can mechanically improve cell proliferation and further supports the great versatility and biocompatibility of the SAW technology for cell manipulation.

Are Portuguese Echinochloa spp. populations still susceptible to propanil?

PubMed

Calha, I M; Matias, A; Neto, M; Rocha, F

2009-01-01

Propanil is the most important herbicide for rice weed management both at world and national level. Rice growers complains of poor control of Echinochloa was monitored in Mondego and Sorraia river valleys, Portugal. Seed samples were collected from the affected area and tested. After the first screening of 37 populations, the sensitivity of six Echinochloa spp. populations to propanil was assessed in a growth chamber dose response study (with seven rates: 0- 7200 g a.i. ha(-1)). Fresh weight was assessed 21 days after treatment and data was analysed using non-linear regression analysis and sensitivity indices (SI = ED80, less sensitive/ ED80, most sensitive) calculated for the two regions surveyed. The rates of 50% of plant growth inhibition (ED50) was calculated from the fitted equations. Four populations where confirmed susceptible with ED50 values ranging from 89 to 1866 g a.i. ha(-1). Two other populations presented ED50 values of 6538 and 9536 g a.i. ha(-1). Mondego and Sorraia SI were 2.35 and 53.55 respectively. The pattern of propanil use in the two regions could explain the higher sensitivity of Mondego populations compared to Sorraia populations. The response to a single dose Petri dish bioassay (360 g a.i. L(-1)) was similar among the six populations, denoting that this method was not so sensitive as the whole plant assay to discriminate between Echinochloa spp. populations. Further studies are needed with more doses and populations since this method allows for an answer within six days, compared with 41 days with the whole plant bioassay.

Biological control of Ascaris suum eggs by Pochonia chlamydosporia fungus.

PubMed

Ferreira, Sebastião Rodrigo; de Araújo, Jackson Victor; Braga, Fábio Ribeiro; Araujo, Juliana Milani; Frassy, Luiza Neme; Ferreira, Aloízio Soares

2011-12-01

Ascaris suum is a gastrointestinal nematode parasite of swines. The aim of this study was to observe Pochonia chlamydosporia fungus on biological control of A. suum eggs after fungus passage through swines gastrointestinal tract. Eighteen pigs, previously dewormed, were randomly divided into three groups: group 1, treated with the fungus isolate VC4; group 2, treated with the fungus isolate VC1 and group 3 did not receive fungus (control). In the treated groups, each animal received a 9 g single dose of mycelium mass containing P. chlamydosporia (VC1 or VC4). Thereafter, animal fecal samples were collected at the following intervals: 8, 12, 24, 36, 48, 72 and 96 h after treatment beginning and these were poured in Petri dishes containing 2% water-agar culture medium. Then, 1,000 A. suum eggs were poured into each dish and kept in an incubator at 26 °C and in the dark for 30 days. After this period, approximately 100 eggs were removed from each Petri dish and morphologically analyzed under light microscopy following the ovicidal activity parameters. The higher percentage observed for isolated VC4 eggs destruction was 57.5% (36 h) after fungus administration and for isolate VC1 this percentage was 45.8% (24 h and 72 h) (p > 0.01). P. chlamydosporia remained viable after passing through the gastrointestinal tract of swines, maintaining its ability of destroying A. suum eggs.

Highly concentrated, ring-shaped phase conversion laser-induced breakdown spectroscopy technology for liquid sample analysis.

PubMed

Lin, Qingyu; Wei, Zhimei; Guo, Hongli; Wang, Shuai; Guo, Guangmeng; Zhang, Zhi; Duan, Yixiang

2017-06-10

A highly concentrated, ring-shaped phase conversion (RSPC) method was developed for liquid sample analysis using the laser-induced breakdown spectroscopy (LIBS) technique. In this work, test samples were prepared by mixing the metal particles with polyvinyl alcohol (PVA) supporter in liquid phase. With heat, the PVA solution solidified inside a modified glass petri dish, forming a metal-enriched polymer ring film. Distinguished from other traditional liquid-to-solid conversing methods, the proposed new method takes advantage of enhanced homogeneity for the target elements inside the ring film. The modified glass petri dish was used to control the ring-shaped concentration. Due to the specially designed circular groove at the bottom of this dish, where the PVA solution and liquid sample mixture accumulated, the target elements were concentrated in this small ring, which is beneficial for enhancing and stabilizing the plasma signals compared to the direct liquid sample analysis using LIBS. The limits of detection for Ag, Cu, Cr, and Ba obtained with the RSPC-LIBS technology were 0.098  μg·mL -1 , 0.18  μg·mL -1 , 0.83  μg·mL -1 , and 0.046  μg·mL -1 , respectively, which provided greater improvement than the direct bulk liquid analysis using LIBS.

A filter paper-based liquid culture system for citrus shoot organogenesis - a mixture-amount experiment

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the effects of a static liquid culture system on shoot regeneration from citrus epicotyl explants. Two citrus types were used, Carrizo citrange and Ridge Pineapple sweet orange. A liquid culture system comprised of a Petri dish, cellulose filter paper dis...

40 CFR 92.128 - Particulate handling and weighing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Particulate handling and weighing. (a) At least 1 hour before the test, place each filter in a closed (to... stabilization period, weigh each filter on the microbalance. This reading is the tare weight and must be recorded. (c) The filter shall then be stored in a covered petri dish or a sealed filter holder until...

40 CFR 92.128 - Particulate handling and weighing.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Particulate handling and weighing. (a) At least 1 hour before the test, place each filter in a closed (to... stabilization period, weigh each filter on the microbalance. This reading is the tare weight and must be recorded. (c) The filter shall then be stored in a covered petri dish or a sealed filter holder until...

40 CFR 92.128 - Particulate handling and weighing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Particulate handling and weighing. (a) At least 1 hour before the test, place each filter in a closed (to... stabilization period, weigh each filter on the microbalance. This reading is the tare weight and must be recorded. (c) The filter shall then be stored in a covered petri dish or a sealed filter holder until...

40 CFR 92.128 - Particulate handling and weighing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Particulate handling and weighing. (a) At least 1 hour before the test, place each filter in a closed (to... stabilization period, weigh each filter on the microbalance. This reading is the tare weight and must be recorded. (c) The filter shall then be stored in a covered petri dish or a sealed filter holder until...

40 CFR 92.128 - Particulate handling and weighing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Particulate handling and weighing. (a) At least 1 hour before the test, place each filter in a closed (to... stabilization period, weigh each filter on the microbalance. This reading is the tare weight and must be recorded. (c) The filter shall then be stored in a covered petri dish or a sealed filter holder until...

Polarity of Spore Germination in Funaria hygrometrica Hedw.

NASA Astrophysics Data System (ADS)

Pundyak, O. I.; Demkiv, O. T.; Khorkavtsiv, O. Ya; Bagrii, B. B.

It is shown that in darkness the spores of moss Funaria hygrometrica Hedw. germinated polarly under the influence of gravity. At the beginning the rhizoids appeared. They grew downwards. Then future chloronematical stolons started to form a germination spore. Usually, they grew upwards. Clinorotation or horizontal placing of Petry dishes could discoordinate such a gravisensitivity.

Effects of irradiation distance on supply of reactive oxygen species to the bottom of a Petri dish filled with liquid by an atmospheric O{sub 2}/He plasma jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawasaki, Toshiyuki, E-mail: kawasaki@nbu.ac.jp; Kusumegi, Shota; Kudo, Akihiro

The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O{sub 3} exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereasmore » similar results could not be obtained for the O{sub 3} exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.« less

Hydrophilic group formation and cell culturing on polystyrene Petri-dish modified by ion-assisted reaction

NASA Astrophysics Data System (ADS)

Kim, Ki-Hwan; Cho, Jun-Sik; Choi, Doo-Jin; Koh, Seok-Keun

2001-04-01

Polystyrene (PS) Petri-dishes were modified by an ion-assisted reaction (IAR) to improve wettability and to supply a suitable surface for cell culturing. Low energy Ar + ions with 1000 eV were irradiated on the surface of PS in oxygen gas environment. Water contact angles of PS were not reduced much by ion irradiation without oxygen gas and had a value of 40°. In the case of ion irradiation with flowing oxygen gas, however, the water contact angles were dropped significantly from 73° to 19°. X-ray photoelectron spectroscopy analysis showed that the hydrophilic groups were formed on the surface of PS by a chemical reaction between unstable chains induced by ion irradiation and the oxygen gas. Newly formed hydrophilic groups were identified as -(C-O)-, -(CO)- and -(CO)-O- bonds. The influence of the surface modification on growth of the rat pheochromocytoma (PC12) cells was investigated. The IAR-treated PS surfaces showed enhanced attachment and growth in PC12 cell culture test.

In vitro ovine articular chondrocyte proliferation: experiments and modelling.

PubMed

Mancuso, L; Liuzzo, M I; Fadda, S; Pisu, M; Cincotti, A; Arras, M; La Nasa, G; Concas, A; Cao, G

2010-06-01

This study focuses on analysis of in vitro cultures of chondrocytes from ovine articular cartilage. Isolated cells were seeded in Petri dishes, then expanded to confluence and phenotypically characterized by flow cytometry. The sigmoidal temporal profile of total counts was obtained by classic haemocytometry and corresponding cell size distributions were measured electronically using a Coulter Counter. A mathematical model recently proposed (1) was adopted for quantitative interpretation of these experimental data. The model is based on a 1-D (that is, mass-structured), single-staged population balance approach capable of taking into account contact inhibition at confluence. The model's parameters were determined by fitting measured total cell counts and size distributions. Model reliability was verified by predicting cell proliferation counts and corresponding size distributions at culture times longer than those used when tuning the model's parameters. It was found that adoption of cell mass as the intrinsic characteristic of a growing chondrocyte population enables sigmoidal temporal profiles of total counts in the Petri dish, as well as cell size distributions at 'balanced growth', to be adequately predicted.

Biocontrol of ticks by entomopathogenic nematodes. Research update.

PubMed

Samish, M; Alekseev, E; Glazer, I

2000-01-01

Entomopathogenic nematodes (EPNs) are lethal to ticks even though they do not use their normal propagation cycle within tick cadavers. The tick Boophilus annulatus was found to be far more susceptible to EPNs than Hyalomma excavatum, Rhipicephalus bursa, or Rhipicephalus sanguineus. Ticks seem to be less susceptible to nematodes when feeding on a host. Preimaginal tick stages were less susceptible to nematodes than adult ticks. The mortality rate of unfed females was highest, followed by unfed males, and engorged females. The virulence of nematodes to ticks varied greatly among different nematode strains. In most cases, the Heterorhabditis sp. strains were the most virulent strains tested in petri dishes. In buckets containing sandy soil sprayed with 50 nematodes/cm2 and engorged B. annulatus females, the LT50 of the ticks was less than five days. The addition of manure to soil or a manure extract to petri dishes reduced nematode virulence. Since ticks spend most of their life cycle in the upper humid layer of the ground, and many nematode strains share this same ecological niche, the use of EPNs for biocontrol of ticks appears promising.

Phage-mediated counting by the naked eye of miRNA molecules at attomolar concentrations in a Petri dish.

PubMed

Zhou, Xin; Cao, Peng; Zhu, Ye; Lu, Wuguang; Gu, Ning; Mao, Chuanbin

2015-10-01

The ability to count biomolecules such as cancer-biomarker miRNAs with the naked eye is seemingly impossible in molecular diagnostics. Here, we show an ultrasensitive naked-eye-counting strategy for quantifying miRNAs by employing T7 phage-a bacteria-specific virus nanoparticle-as a surrogate. The phage is genetically engineered to become fluorescent and capable of binding a miRNA-capturing gold nanoparticle (GNP) in a one-to-one manner. Target miRNAs crosslink the resultant phage-GNP couple and miRNA-capturing magnetic microparticles, forming a sandwich complex containing equimolar phage and miRNA. The phage is then released from the complex and developed into one macroscopic fluorescent plaque in a Petri dish by plating it in a host bacterial medium. Counting the plaques by the naked eye enables the quantification of miRNAs with detection limits of ∼3 and ∼5 aM for single-target and two-target miRNAs, respectively. This approach offers ultrasensitive and convenient quantification of disease biomarkers by the naked eye.

Phage-mediated counting by the naked eye of miRNA molecules at attomolar concentrations in a Petri dish

NASA Astrophysics Data System (ADS)

Zhou, Xin; Cao, Peng; Zhu, Ye; Lu, Wuguang; Gu, Ning; Mao, Chuanbin

2015-10-01

The ability to count biomolecules such as cancer-biomarker miRNAs with the naked eye is seemingly impossible in molecular diagnostics. Here, we show an ultrasensitive naked-eye-counting strategy for quantifying miRNAs by employing T7 phage--a bacteria-specific virus nanoparticle--as a surrogate. The phage is genetically engineered to become fluorescent and capable of binding a miRNA-capturing gold nanoparticle (GNP) in a one-to-one manner. Target miRNAs crosslink the resultant phage-GNP couple and miRNA-capturing magnetic microparticles, forming a sandwich complex containing equimolar phage and miRNA. The phage is then released from the complex and developed into one macroscopic fluorescent plaque in a Petri dish by plating it in a host bacterial medium. Counting the plaques by the naked eye enables the quantification of miRNAs with detection limits of ~3 and ~5 aM for single-target and two-target miRNAs, respectively. This approach offers ultrasensitive and convenient quantification of disease biomarkers by the naked eye.

Wavelength dependent recovery of UV-mediated damage: Tying up the loose ends of optical based powdery mildew management.

PubMed

Suthaparan, Aruppillai; Pathak, Ranjana; Solhaug, Knut Asbjørn; Gislerød, Hans Ragnar

2018-01-01

Controlled environment chamber experiments at Petri dish level were conducted to examine the wavelength and dose dependent efficacy of ultraviolet (UV) radiation, the recovery action potential of optical radiation applied concomitantly/subsequently to effective UV treatment, and the lapse time between UV treatment and subsequent exposure to recovery wavelength on germination efficiency of Oidium neolycopersici conidia. Conidia of eight- to nine-day-old colonies were dusted on water agar surface in Petri dishes and exposed to UV treatments (without lid). Immediately after UV treatments, Petri dishes were sealed and incubated in darkness or differing optical environments generated using seven different radiation sources (range 290nm to 780nm). Twenty-four hours after UV treatment, fifty conidia from each sample were assessed for germination. Compared to non-UV controls, <10% of the conidia germinated after 30s of exposure to 254nm or 283nm UV and subsequent dark incubation. Conidia germination was almost negligible if the exposure duration increased to 4min. Germination was about 60% with broad spectrum UV after 1min of exposure, and about 35% after 2 to 4min of exposure. There was no reduction of conidia germination with the exposure of ≤4min with 310nm. With the tested wavelength and dose ranges, germination recovery was effective in the 350nm to 500nm range. Germination efficiency of conidia treated with effective UV was significantly higher (>73%) if incubated subsequently in the 350nm to 500nm range (germination recovery). Furthermore, germination recovery depends on the characteristics of UV treatment (wavelength, and duration of exposure) and the lapse time between UV treatment and subsequent exposure to optical radiation in the recovery range. The findings of this study provide key criteria for wavelength selection, combination and application time in the optical radiation range, enabling improved design of optical based management strategies against powdery mildews. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid Turn Around BRIC-PDFU Payload: A New Paradigm for Spaceflight Experiments

NASA Technical Reports Server (NTRS)

Levine, Howard G.; Slater, K. A.; Cox, D. R.

2010-01-01

In 2009, NASA's Fundamental Space Biology program provided an opportunity for investigators to propose for a quick-turn-around multi-user spaceflight experiment that focused on the model plant species Arabidopsis thaliana. This was a passive payload with no on-orbit power or communications available. An NRA was rapidly written (8/09), released (NNH09ZTT004N; 9/09), proposals were received (11/09) and peer reviewed with 3 PI groups selected for flight (1/10): (1) A-L Paul, University of Florida, (2) E. Blancaflor, Noble Foundation, (3) J. Kiss, Miami University. The investigators flew Arabidopsis seeds or callus cultures of their choosing (plated onto 60 mm diameter Petri dishes containing agarsolidified media) on the STS-131 Space Shuttle mission (launched 4/5/10) and the resulting plant tissues returned to earth on 4/20/10. Each petri dish was placed inside its own Petri Dish Fixation Unit (PDFU), which was assembled and loaded with either formaldehyde, glutaraldehyde or RNAlater for crew-facilitated on-orbit fixation. Five PDFUs plus a temperature data logger were loaded into each of 8 BRIC-PDFUs (Biological Research In Canisters PDFU). All eight BRIC-PDFUs were loaded into a half tray along with actuator equipment that the crew used for the fixations. Pre-flight turn-over was 28 hours prior to launch. The BRIC-PDFU assemblies were removed from the orbiter and handed over to the investigator teams for processing 5-6 hours after landing. This payload demonstrated a rapid response turnaround for flying multiple peer-reviewed science investigations using previously flown hardware and minimal ISS-resources. The approach used reduced both hardware/certification and PI costs. The time waiting for a flight opportunity for the selected Pls was minimal. This new paradigm for spaceflight experiments may provide a model for future flight research opportunities. The ultimate goal is to fly as many investigators as rapidly as possible and reinvigorate the space biology community while obtaining high-quality, peer-reviewed science.

Cell-populated collagen lattice contraction model for the investigation of fibroblast collagen interactions.

PubMed

Ehrlich, H Paul; Moyer, Kurtis E

2013-01-01

The fibroblast-populated collagen lattice (FPCL) was intended to act as the dermal component for "skin-equivalent" or artificial skin developed for skin grafting burn patients. The "skin-equivalent" was clinically unsuccessful as a skin graft, but today it is successfully used as a dressing for the management of chronic wounds. The FPCL has, however, become an instrument for investigating cell-connective tissue interactions within a three-dimensional matrix. Through the capacity of cell compaction of collagen fibrils, the FPCL undergoes a reduction in volume referred to as lattice contraction. Lattice contraction proceeds by cell-generated forces that reduce the water mass between collagen fibers, generating a closer relationship between collagen fibers. The compaction of collagen fibers is responsible for the reduction in the FPCL volume. Cell-generated forces through the linkage of collagen fibers with fibroblast's cytoskeletal actin-rich microfilament structures are responsible for the completion of the collagen matrix compaction. The type of culture dish used to cast FPCL as well as the cell number will dictate the mechanism for compacting collagen matrices. Fibroblasts, at moderate density, cast as an FPCL within a petri dish and released from the surface of the dish soon after casting compact collagen fibers through cell tractional forces. Fibroblasts at moderate density cast as an FPCL within a tissue culture dish and not released for 4 days upon release show rapid lattice contraction through a mechanism of cell contraction forces. Fibroblasts at high density cast in an FPCL within a petri dish, released from the surface of the dish soon after casting, compact a collagen lattice very rapidly through forces related to cell elongation. The advantage of the FPCL contraction model is the study of cells in the three-dimensional environment, which is similar to the environment from which these cells were isolated. In this chapter methods are described for manufacturing collagen lattices, which assess the three forces involved in compacting and/or organizing collagen fibrils into thicker collagen fibers. The clinical relevance of the FPCL contraction model is related to advancing our understanding of wound contraction and scar contracture.

Pure culture response of ectomycorrhizal fungi to imposed water stress

Treesearch

Mark D. Coleman; Caroline S. Bledsoe; William Lopushinsky

1989-01-01

The ability of ectomycorrhizal fungal isolates to tolerate imposed water stress in pure culture was examined in 55 isolates of 18 species. Water potential treatments, adjusted with polyethylene glycol, were applied to Petri dish units. These units allowed colony diameter measurements of fungi grown on liquid media. Delayed growth initiation and inhibition of growth...

Cytology and Genetics of Sexual Incompatibility in Didymella rabiei

Treesearch

A. Dan Wilson; W.J. Kaiser

1995-01-01

Mating crosses in all possible combinations between 15 monoascosporic isolates of Didymella rabiei (Ascomycotina, Dothideales), derived from diseased chickpea stems collected at a single location in Genesee, Idaho, were prepared on sterile chickpea stem pieces incubated on moist sterile filter papers in glass petri dishes for 5-6 weeks at 10°C or in...

Improved efficiency of plant regeneration from protoplasts of eggplant Solanum melongena L.

PubMed

Guri, A; Izhar, S

1984-12-01

Eggplant (Solanum melongena L.) mesophyll protoplasts were obtained from in vitro growing plants of line 410 and cv. 'Classic'. Relatively high (15%) plating efficiency was achieved using petri dishes with alternate quadrants containing reservoir medium (R medium + 1% activated charcoal) and culture medium. Shoot regeneration occurred within 6 weeks following initiation of protoplast culture.

Undesirable dispersal of eggs and early-stage nymphs of the bed bug Hemiptera: cimicidae) by static electricity and air currents

USDA-ARS?s Scientific Manuscript database

Movement of whole live insects or other small arthropods attributed to static electricity has been reported only rarely. While viewing bed bugs in plastic or glass Petri dishes using a dissecting microscope, individual eggs and early stage nymphs were occasionally observed to move suddenly and rapid...

Basil oil fumigation increases radiation sensitivity in adult Sitophilus oryzae (Coleoptera: Curculionidae).

USDA-ARS?s Scientific Manuscript database

The biological activity of basil (Ocimum basilicum L.) oil was tested against the stored product pest rice weevil, Sitophilus oryzae(L.). Adult weevils were exposed to seven different concentrations of basil oil ranging from 0.12 µl/ml-0.60 µl/ml in Petri dishes and mortality was assessed at 3,4 and...

30 CFR 7.89 - Test to determine the particulate index.

Code of Federal Regulations, 2012 CFR

2012-07-01

... filters as follows: (i) At least 1 hour before the test, each filter (pair) shall be placed in a closed... the stabilization period, each filter (pair) shall be weighed. The reading is the tare weight. (iii) The filter (pair) shall then be stored in a closed petri dish or a filter holder, both of which shall...

30 CFR 7.89 - Test to determine the particulate index.

Code of Federal Regulations, 2010 CFR

2010-07-01

... filters as follows: (i) At least 1 hour before the test, each filter (pair) shall be placed in a closed... the stabilization period, each filter (pair) shall be weighed. The reading is the tare weight. (iii) The filter (pair) shall then be stored in a closed petri dish or a filter holder, both of which shall...

30 CFR 7.89 - Test to determine the particulate index.

Code of Federal Regulations, 2014 CFR

2014-07-01

... filters as follows: (i) At least 1 hour before the test, each filter (pair) shall be placed in a closed... the stabilization period, each filter (pair) shall be weighed. The reading is the tare weight. (iii) The filter (pair) shall then be stored in a closed petri dish or a filter holder, both of which shall...

30 CFR 7.89 - Test to determine the particulate index.

Code of Federal Regulations, 2011 CFR

2011-07-01

... filters as follows: (i) At least 1 hour before the test, each filter (pair) shall be placed in a closed... the stabilization period, each filter (pair) shall be weighed. The reading is the tare weight. (iii) The filter (pair) shall then be stored in a closed petri dish or a filter holder, both of which shall...

30 CFR 7.89 - Test to determine the particulate index.

Code of Federal Regulations, 2013 CFR

2013-07-01

... filters as follows: (i) At least 1 hour before the test, each filter (pair) shall be placed in a closed... the stabilization period, each filter (pair) shall be weighed. The reading is the tare weight. (iii) The filter (pair) shall then be stored in a closed petri dish or a filter holder, both of which shall...

Behavior Performance of Diuraphis noxia (Homoptera: Aphididae) on Fungal Endophyte-Infected and Uninfected Perennial Ryegrass

Treesearch

S.L. Clement; D.G. Lester; A. Dan Wilson; K.S. Pike

1992-01-01

The behavior and performance of the Russian wheat aphid, Diuraphis noxia (Mordvilko), on fungal endophyte-infected and endophyte-free perennial ryegrass, Lolium perenne L., was investigated in the laboratory and field. Aphids did not select endophyte-free over endophyte-infected leaf sheaths and stem segments in petri dish preference tests....

Demonstrations of the Action and Reaction Law and the Energy Conservation Law Using Fine Spherical Plastic Beads

ERIC Educational Resources Information Center

Khumaeni, A.; Tanaka, S.; Kobayashi, A.; Lee, Y. I.; Kurniawan, K. H.; Ishii, K.; Kagawa, K.

2008-01-01

Equipment for demonstrating Newton's third law and the energy conservation law in mechanics have successfully been constructed utilizing fine spherical plastic beads in place of metal ball bearings. To demonstrate Newton's third law, special magnetized Petri dishes were employed as objects, while to examine the energy conservation law, a…

Induction of soybean resistance to the Mexican bean beetle (Coleoptera: Coccinellidae)

Treesearch

A.L. Iverson; R.B. Hammond; L.R. Iverson

2001-01-01

We tested chemical and insect feeding-induced insect resistance on soybean plants.The chemical induction effects of jasmonic acid (JA) and salicylic acid (SA) were investigated. We also evaluated the effects of plants stressed with previous insect herbivory. A larval antibiosis screening technique (LAST) and a preference test were performed in petri dishes using...

Characterizing parameters of Jatropha curcas cell cultures for microgravity studies

NASA Astrophysics Data System (ADS)

Vendrame, Wagner A.; Pinares, Ania

2013-06-01

Jatropha (Jatropha curcas) is a tropical perennial species identified as a potential biofuel crop. The oil is of excellent quality and it has been successfully tested as biodiesel and in jet fuel mixes. However, studies on breeding and genetic improvement of jatropha are limited. Space offers a unique environment for experiments aiming at the assessment of mutations and differential gene expression of crops and in vitro cultures of plants are convenient for studies of genetic variation as affected by microgravity. However, before microgravity studies can be successfully performed, pre-flight experiments are necessary to characterize plant material and validate flight hardware environmental conditions. Such preliminary studies set the ground for subsequent spaceflight experiments. The objectives of this study were to compare the in vitro growth of cultures from three explant sources (cotyledon, leaf, and stem sections) of three jatropha accessions (Brazil, India, and Tanzania) outside and inside the petriGAP, a modified group activation pack (GAP) flight hardware to fit petri dishes. In vitro jatropha cell cultures were established in petri dishes containing a modified MS medium and maintained in a plant growth chamber at 25 ± 2 °C in the dark. Parameters evaluated were surface area of the explant tissue (A), fresh weight (FW), and dry weight (DW) for a period of 12 weeks. Growth was observed for cultures from all accessions at week 12, including subsequent plantlet regeneration. For all accessions differences in A, FW and DW were observed for inside vs. outside the PetriGAPs. Growth parameters were affected by accession (genotype), explant type, and environment. The type of explant influenced the type of cell growth and subsequent plantlet regeneration capacity. However, overall cell growth showed no abnormalities. The present study demonstrated that jatropha in vitro cell cultures are suitable for growth inside PetriGAPs for a period of 12 weeks. The parameters evaluated in this study provide the basic ground work and pre-flight assessment needed to justify a model for microgravity studies with jatropha in vitro cell cultures. Future studies should focus on results of experiments performed with jatropha in vitro cultures in microgravity.

Video Tracking Protocol to Screen Deterrent Chemistries for Honey Bees.

PubMed

Larson, Nicholas R; Anderson, Troy D

2017-06-12

The European honey bee, Apis mellifera L., is an economically and agriculturally important pollinator that generates billions of dollars annually. Honey bee colony numbers have been declining in the United States and many European countries since 1947. A number of factors play a role in this decline, including the unintentional exposure of honey bees to pesticides. The development of new methods and regulations are warranted to reduce pesticide exposures to these pollinators. One approach is the use of repellent chemistries that deter honey bees from a recently pesticide-treated crop. Here, we describe a protocol to discern the deterrence of honey bees exposed to select repellent chemistries. Honey bee foragers are collected and starved overnight in an incubator 15 h prior to testing. Individual honey bees are placed into Petri dishes that have either a sugar-agarose cube (control treatment) or sugar-agarose-compound cube (repellent treatment) placed into the middle of the dish. The Petri dish serves as the arena that is placed under a camera in a light box to record the honey bee locomotor activities using video tracking software. A total of 8 control and 8 repellent treatments were analyzed for a 10 min period with each treatment was duplicated with new honey bees. Here, we demonstrate that honey bees are deterred from the sugar-agarose cubes with a compound treatment whereas honey bees are attracted to the sugar-agarose cubes without an added compound.

[How do metallic middle ear implants behave in the MRI?].

PubMed

Kwok, P; Waldeck, A; Strutz, J

2003-01-01

Magnetic resonance imaging (MRI) has gained in frequency and importance as a diagnostic procedure. In respect to the close anatomical relationship in the temporal bone it is necessary to know whether it is hazardous to patients with metallic middle ear implants regarding displacement and rise in temperature. For the MR image quality artefacts caused by metallic prostheses should be low. Four different stapes prostheses made from titanium, gold, teflon/platinum and teflon/steel, a titanium total ossicular reconstruction prosthesis (TORP) and two ventilation tubes (made from titanium and gold) were tested in a 1.5 Tesla MRI machine regarding their displacement. All objects were first placed in a petri dish, then suspended from a thread and finally immersed in a dish filled with Gadolinium. Temperature changes of the implants were recorded by a pyrometer. None of the implants moved when they were placed in the petri dish or suspended from the thread. On the water surface the teflon/platinum and the teflon/steel pistons adjusted their direction with their axis longitudinally to the MRI scanner opening and the teflon/steel piston floated towards the MRI-machine when put close enough to the scanner opening. No rise in temperature was recorded. All implants showed as little artefacts that would still make an evaluation of the surrounding tissue possible. Patients with any of the metallic middle ear implants that were examined in this study may undergo MRI-investigations without significant adverse effects.

A new UV-LED device for automatic disinfection of stethoscope membranes.

PubMed

Messina, Gabriele; Burgassi, Sandra; Messina, Daniele; Montagnani, Valerio; Cevenini, Gabriele

2015-10-01

Stethoscopes are widely used by doctors and nurses. Poor stethoscope hygiene is a potential source of nosocomial infection. This study aimed to propose an innovative solution, based on the latest advances in ultraviolet (UV) light-emitting diodes (LEDs), for disinfecting stethoscope membranes automatically and efficiently. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis were sown on 28 stethoscope membranes and then transferred to Petri dishes. Treatment involved illuminating exposed Petri dishes with a UVC LED for 1 minute. For each microbe, the number of colony-forming units (cfu) at 36°C was compared in control and treated dishes using the Wilcoxon signed-rank test. The Kruskal-Wallis test was used to assess percent reductions in bacteria. Statistical significance was set at 99%. A significant reduction in cfu counts after UV treatment (P < .01) was found for all bacteria: 85.5% for E faecalis, 87.5% for S aureus, 94.3% for E coli, and 94.9% for P aeruginosa . No significant differences in percent reduction in cfu were found between bacteria (P > .01). The stethoscope, symbol of medicine and health care professionals, has been demonstrated to be a carrier of microorganisms. The treatment technique was effective and efficient in disinfecting the membranes. These promising results represent a step forward toward eliminating stethoscope membrane contamination with an innovative approach. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

The sensitivity of an hydroponic lettuce root elongation bioassay to metals, phenol and wastewaters.

PubMed

Park, Jihae; Yoon, Jeong-Hyun; Depuydt, Stephen; Oh, Jung-Woo; Jo, Youn-Min; Kim, Kyungtae; Brown, Murray T; Han, Taejun

2016-04-01

The root elongation bioassay is one of the most straightforward test methods used for environmental monitoring in terms of simplicity, rapidity and economy since it merely requires filter paper, distilled water and Petri dishes. However, filter paper as a support material is known to be problematic as it can reduce the sensitivity of the test. The newly developed hydroponic method reported here differs from the conventional root elongation method (US EPA filter paper method) in that no support material is used and the exposure time is shorter (48 h in this test versus 120 h in the US EPA test). For metals, the hydroponic test method was 3.3 (for Hg) to 57 (for Cu) times more sensitive than the US EPA method with the rank orders of sensitivity, estimated from EC50 values, being Cu≥Cd>Ni≥Zn≥Hg for the former and Hg≥Cu≥Ni≥Cd≥Zn for the latter methods. For phenol, the results did not differ significantly; EC50 values were 124 mg L(-1) and 108-180 mg L(-1) for the hydroponic and filter paper methods, respectively. Lettuce was less sensitive than daphnids to wastewaters, but the root elongation response appears to be wastewater-specific and is especially sensitive for detecting the presence of fluorine. The new hydroponic test thus provides many practical advantages, especially in terms of cost and time-effectiveness requiring only a well plate, a small volume of distilled water and short exposure period; furthermore, no specialist expertise is required. The method is simpler than the conventional EPA technique in not using filter paper which can influence the sensitivity of the test. Additionally, plant seeds have a long shelf-life and require little or no maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

Inhibition of Ageratina adenophora on spore germination and gametophyte development of Macrothelypteris torresiana.

PubMed

Zhang, Kai-Mei; Shi, Lei; Jiang, Chuang-Dao; Li, Zhen-Yu

2008-05-01

Allelopathy of Ageratina adenophora plays an important role in its invasion. However, we have little knowledge of its allelpathic effects on ferns. In Petri dish bioassays, the inhibitory potential of aqueous leachates from roots, stems and leaves of A. adenophora was studied on the spore germination and gametophyte development of Macrothelypteris torresiana. All leachates inhibited the spore germination and growth of the first rhizoid of M. torresiana and inhibitory effects increased with increasing leachate concentrations. Root leachates proved most inhibitory. Gametophyte rhizoids of M. torresiana treated with stem and leaf leachates of A. adenophora were erect, which was similar to those of the control. However, gametophyte rhizoids of M. torresiana treated with root leachates of A. adenophora were erect, but also curving or swollen. Moreover, curving and swollen rhizoids increased with increasing concentrations. As time went by, rhizoids treated with root leachates were not so curved and the swelling almost disappeared. Possible causes are discussed in the present study. The increasing concentrations of leaf leachates also delayed the stages of gametophyte development. With the treatment of root leachates, the delay was more obvious. Thus A. adenophora inhibited the spore germination and gametophyte development of M. torresiana and the root leachates were most inhibitory.

Physiological assessment and path coefficient analysis to improve evaluation of alfalfa autotoxicity.

PubMed

Chon, Sang-Uk; Nelson, C Jerry; Coutts, John H

2003-11-01

Reseeding of alfalfa is affected until autotoxic chemicals break down or are dispersed, often requiring a year or more. Bioassays of seed germination and early seedling growth, on agar medium in petri dishes, were conducted to evaluate autotoxic responses of 20 alfalfa germplasms to water-soluble extracts of alfalfa leaf tissue. Root length, 120 hr after placing imbibed seed on agar, was more sensitive to the autotoxin(s) than was hypocotyl length, germination speed, and final germination percentage. Path coefficient analyses showed variation in root length had 7-17 times more effect than variation in hypocotyl length in determining autotoxic effects on total seedling length. Although variations in seed size and germination rate were negatively associated (P < 0.05) with final root length, the autotoxin had little effect on these factors relative to that on root length. Germplasms in the control differed (P < 0.05) in root length, requiring tolerance to be evaluated as percent of control. Germplasms, as percent of control, differed significantly (P < 0.05) at extract concentrations of 1.0 and 4.0 g l(-1), but the range and LSD were more favorable for selection at 1.0 g l(-1). Root length is appropriate for genetic assessments of tolerance to the autotoxin when expressed as percent of control.

Microecology: Using Fast-Growing Filamentous Fungi to Study the Effects of Environmental Gradients on the Growth Patterns of Hyphae

ERIC Educational Resources Information Center

Delpech, Roger

2004-01-01

This paper describes some simple and rapid techniques for examining the growth responses of fungal hyphae cultivated on environmental gradients. The creation of such gradients using agar-based growth media in petri dishes is explained, along with recommendations for quantitative macroscopic and microscopic measurements. The intention is to provide…

Minibrain Storm : Cerebral Organoids Aren't Real Brains?But They Provide a Powerful Platform for Modeling Brain Diseases Like Zika Infection, Alzheimer's, and Even Autism.

PubMed

Fischer, Shannon

2017-01-01

Floating in a Petri dish, they look like tiny tapioca pearls in peach broth, a couple dozen in number and none much larger than the tip of a ballpoint pen. But under a microscope, dense, lumpy bodies come into focus, outlined by wispy coronas.

The Effect of Culture Methods and Serum Supplementation on Developmental Competence of Bovine Embryos Cultured In Vitro

USDA-ARS?s Scientific Manuscript database

The objective of this study was to compare the developmental competence of bovine in vitro fertilized embryos in three different culture methods; microdrop method (50 µl of medium under mineral oil in petri dishes) compared to tube methods (1 ml of medium in tubes) with or without oil overlay, and t...

Growth of Pleurotus ostreatus on wheat straw and wheat-grain-based media: Biochemical aspects and preparation of mushroom inoculum.

PubMed

Sainos, E; Díaz-Godínez, G; Loera, O; Montiel-González, A M; Sánchez, C

2006-10-01

Mycelial growth, intracellular activity of proteases, laccases and beta-1,3-glucanases, and cytoplasmic protein were evaluated in the vegetative phase of Pleurotus ostreatus grown on wheat straw and in wheat-grain-based media in Petri dishes and in bottles. The productivity of the wheat straw and wheat-grain-based spawn in cylindrical polyethylene bags containing 5 kg of chopped straw was also determined. We observed high activity of proteases and high content of intracellular protein in cultures grown on wheat straw. This suggests that the proteases are not secreted into the medium and that the protein is an important cellular reserve. On the contrary, cultures grown on wheat straw secreted laccases into the medium, which could be induced by this substrate. P. ostreatus grown on media prepared with a combination of wheat straw and wheat grain showed a high radial growth rate in Petri dishes and a high level of mycelial growth in bottles. The productivities of wheat straw and wheat-grain-based spawn were similar. Our results show that cheaper and more productive mushroom spawn can be prepared by developing the mycelium on wheat straw and wheat-grain-based substrates.

Differentiation and Tropisms in Space-Grown Moss

NASA Technical Reports Server (NTRS)

Sack, Fred D.; Kern, Volker

1999-01-01

This grant supported a Space Shuttle experiment on the effects of microgravity on moss cells. Moss provides a rich system for gravitational and spaceflight research. The early phase of the moss life cycle consists of chains of cells that only grow only at their tips. In the moss Ceratodon purpureus these filaments (protonemata) grow away from gravity in the dark, in a process called gravitropism. The tipmost cells, the apical cells, contain heavy starch-filled bodies called amyloplasts that probably function in g-sensing and that sediment within the apical cell. The SPM-A (Space Moss aka SPAM) experiment flew in November - December, 1997 on STS-87 as part of the Collaborative US Ukrainian Experiment (CLTE). The experiment was accommodated in hardware purpose-built by NASA KSC and Bionetics and included Petri Dish Fixation Units (PDFU) and BRIC-LEDs. Together, this hardware allowed for the culture of the moss on agar in commercial petri dishes, for unilateral illumination with red light of varying intensity, and for chemical fixation in situ. The key findings of the spaceflight were quite unexpected. Neither the orientation of tip-growth nor the distribution of amyloplasts was random in microgravity.

The Effect of Antibacterial Formula Hand Cleaners on the Elimination of Microbes on Hands

NASA Astrophysics Data System (ADS)

Coleman, J. R.

2002-05-01

: The purpose of this project is to find out which one of the antibacterial hand cleanser (antibacterial bar soap, antibacterial liquid hand soap, and liquid hand sanitizer) is more effective in eliminating microbes. If antibacterial- formula liquid hand soap is used on soiled hands, then it will be more effective in eliminating microbes. Germs are microorganisms that cause disease and can spread from person-to-person. Bacteria are a kind of microbe, an example of which is Transient Flora that is often found on hands. Hand washing prevents germs from spreading to others. During the procedure, swabs were used to take samples before and after the soiled hands had been washed with one of the antibacterial hand cleansers. Nutrient Easygel was poured into petri dishes to harden for 1 day, and then samples were swabbed on the gel. The Petri dishes were placed in an incubator for 24 hours, and then data was recorded accordingly. The antibacterial liquid hand soap was sufficient in eliminating the majority of bacteria. The hands had 65% of the bacteria on them, and after the liquid hand soap was used only 37% of the bacteria remained.

Metabolic Profiling Directly from the Petri Dish Using Nanospray Desorption Electrospray Ionization Imaging Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watrous, Jeramie D.; Roach, Patrick J.; Heath, Brandi S.

2013-11-05

Understanding molecular interaction pathways in complex biological systems constitutes a treasure trove of knowledge that might facilitate the specific, chemical manipulation of the countless microbiological systems that occur throughout our world. However, there is a lack of methodologies that allow the direct investigation of chemical gradients and interactions in living biological systems, in real time. Here, we report the use of nanospray desorption electrospray ionization (nanoDESI) imaging mass spectrometry for in vivo metabolic profiling of living bacterial colonies directly from the Petri dish with absolutely no sample preparation needed. Using this technique, we investigated single colonies of Shewanella oneidensis MR-1,more » Bacillus subtilis 3610, and Streptomyces coelicolor A3(2) as well as a mixed biofilm of S. oneidensis MR-1 and B. subtilis 3610. Data from B. subtilis 3610 and S. coelicolor A3(2) provided a means of validation for the method while data from S. oneidensis MR-1 and the mixed biofilm showed a wide range of compounds that this bacterium uses for the dissimilatory reduction of extracellular metal oxides, including riboflavin, iron-bound heme and heme biosynthetic intermediates, and the siderophore putrebactin.« less

[Conjugated variability of spontaneous activity and behavioral response to olfactory stimuli in the taiga tick (Ixodes persulcatus)].

PubMed

Romashchenko, A V; Shnaĭder, E P; Petrovskiĭ, D V; Moshkin, M P

2013-01-01

According to -the automatic tracing of the movement of ticks in a Petri dish, motivational variability of the spontaneous activity and behavioral response of the taiga tick to olfactory stimuli was analyzed. In the studied sample, two groups of ticks that differ in the movement trajectory in the absence of stimulus were isolated, including ticks that mainly moved on the edge of the dish at maximum accessible height (group 1) and ticks that mainly moved at the bottom and wall of the dish (group 2). It was registered that ticks of group 1 (as opposed to ticks of group 2) demonstrated a pronounced behavioral response to olfactory stimuli (human synthetic pheromones and ammonia) and negative geotaxis. It was established that belonging to these groups depended On the time of day when the testing was performed and did not depend on the physiological age and infectious status.

BRIC-60: Biological Research in Canisters (BRIC)-60

NASA Technical Reports Server (NTRS)

Richards, Stephanie E. (Compiler); Levine, Howard G.; Romero, Vergel

2016-01-01

The Biological Research in Canisters (BRIC) is an anodized-aluminum cylinder used to provide passive stowage for investigations evaluating the effects of space flight on small organisms. Specimens flown in the BRIC 60 mm petri dish (BRIC-60) hardware include Lycoperscion esculentum (tomato), Arabidopsis thaliana (thale cress), Glycine max (soybean) seedlings, Physarum polycephalum (slime mold) cells, Pothetria dispar (gypsy moth) eggs and Ceratodon purpureus (moss).

The Effects of Ammonium Perchlorate on Reproduction and Development of Amphibians

DTIC Science & Technology

2008-01-01

Abstract: Ammonium perchlorate is a pervasive pollutant primarily from rocket fuel and fertilizers . It is know , among other things , to affect...females, their ovulated eggs collected, and in vitro fertilization conducted. Healthy ovulated eggs were selected and placed in Petri dishes...used and fertilization accomplished in vitro in the presence of perchlorate concentrations. *These tasks were not completed. Studies with Sodium

Summary Report on Visit to Departamento de Investigation Centro Ramon Y Cajal Madrid, Spain.

DTIC Science & Technology

1984-10-30

Over one hundred colonies of Gram negative bacteria ( Lactobacillus acidophilus ) were cultured at 380 C in Petri dishes for 72 hours. The inoculum...within the various laboratories. He was particularly excited about studies using Lactobacillus bacteria and the work involving Drosophila melanogaster...therapy (0-40 Gauss) caUsed a 40 %reduction in the number of Lactobacillus colonies. ........................ . . .. . .. . .. . .. . . RAT MODEL TO

Biological control of infective larvae of Ancylostoma spp. in beach sand.

PubMed

De Mello, Ingrid Ney Kramer; Braga, Fabio R; Monteiro, Thalita S Avelar; Freitas, Leandro G; Araujo, Juliana M; Soares, Filippe E Freitas; Araújo, Jackson V

2014-01-01

Geohelminths are parasites that stand out for their prevalence and wide distribution, depending on the soil for their transmission. The aim of this work was to evaluate the predatory capacity of the fungal isolate of the genus Duddingtonia (CG768) on third stage larvae (L3) of Ancylostoma spp. in beach sand under laboratory conditions. In the assay A five treatment groups and 1 control group were formed. The treatment groups contained 5000, 10,000, 15,000, 20,000 or 25,000 chlamydospores of the fungal isolate and 1000 Ancylostoma spp. L3 in pots containing 30g of sand. The control group (without fungus) contained only 1000 Ancylostoma spp. L3 and distilled water in pots with 30g of sand. Evidence of predatory activity was observed at the end of 15 days, where we observed the following percentages of reduction of L3: Group 1 (4.5%); Group 2 (24.5%); Group 3 (59.2%); Group 4 (58.8%); Group 5 (63%). However, difference was noted (p<0.01) only at concentrations 15,000, 20,000 and 25,000 in relation to control group. In the assay B two groups were formed in Petri dishes of 9cm in diameter containing agar water 2% medium. In the treated group, each Petri dish contained 500 Ancylostoma spp. L3 and 5g of sand containing the isolate CG 768 at a concentration of 25,000 chlamydospores/g of sand, and the control group (without fungus) contained only 500 L3. At the end of 7 days the non-predation L3 of Petri dishes using the method of Baermann were recovered. Difference (p<0.01) between groups on reducing the average number of Ancylostoma spp. L3 (percent reduction of 84%) was observed. The results of this study confirm earlier work on the efficiency of the Duddingtonia genus in the control of Ancylostoma spp. infective larvae. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Developmental capacity of Ascaridia galli eggs is preserved after anaerobic storage in faeces.

PubMed

Tarbiat, B; Rahimian, S; Jansson, D S; Halvarsson, P; Höglund, J

2018-05-15

The reliability of the results of in vitro studies such as detection of anthelmintic resistance often depends on the ability of the parasite eggs to develop under laboratory conditions. The aim of this study was to assess the embryonation capability of the chicken roundworm Ascaridia galli eggs after storage under different conditions. Two storage media for parasite eggs were used; faeces or water. Eggs in petri dishes (90 dishes in total) containing faces or water media were first exposed either to aerobic or anaerobic conditions at different temperatures (4 °C /+O 2 , 4 °C /-O 2 , 25 °C/-O 2 ) for a maximum of 72 days. Every second week, materials from petri dishes in triplicates were recovered and incubated aerobically for two weeks at 25 °C. After the incubation, 200-300 eggs from each petri shish (sampling unit) were counted and the number of embryonated eggs was determined. Data was analyzed in R (version 3.4.3) A logistic regression model with the probability of an egg to embryonate as dependent variable and conditions, storage medium and time points as fixed effects with quasibinomial distribution was run. Least-square means were calculated and pairwise comparisons were made with the fixed effect factors (condition, storage medium and time point). Eggs in faeces had a significantly (p ˂ 0.05) higher embryonation than those in water, irrespective of storage conditions. At 4 °C embryonation tended to decline over time under aerobic conditions irrespective of the storage medium, whereas it remained constant following storage at anaerobic conditions. In contrast, anaerobic storage at the 25 °C negatively affected egg development in both media, except for day 14 in faeces. Our major finding was that eggs in faeces under anaerobic conditions and at 4 °C retained the highest rate of development, with a minimum decline in their developmental capacity over time compared to cleaned eggs stored in water. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluating the effectiveness of a Mexican strain of Duddingtonia flagrans as a biological control agent against gastrointestinal nematodes in goat faeces.

PubMed

Ojeda-Robertos, N F; Mendoza-de Gives, P; Torres-Acosta, J F J; Rodríguez-Vivas, R I; Aguilar-Caballero, A J

2005-06-01

The use of Duddingtonia flagrans in the control of goat nematodes was investigated. Initially, the time of passage of chlamydospores through the digestive tract of goats was evaluated. Two groups of seven parasite-free kids were formed. Group A received a single dose of 3.5x10(6) D. flagrans chlamydospores (FTHO-8 strain) per kg of live weight. Group B did not receive any chlamydospores. Faeces were obtained from each kid daily from day 4 prior to inoculation until day 5 post-inoculation (PI) and were placed in Petri dishes containing water agar. Gastrointestinal nematode infective larvae were added to each Petri dish and incubated at 25 degrees C for 7 days. Petri dishes were examined to detect the fungus and trapped nematodes. A second trial evaluated the effect of D. flagrans on the number of gastrointestinal nematode larvae harvested from goat faecal cultures in naturally infected goats. Two groups of seven goats were formed. The treated group received a single dose of 3.5x10(6) D. flagrans chlamydospores per kg of liveweight. The control group did not receive any chlamydospores. Faeces were obtained twice daily from each kid. Two faecal cultures were made for each kid. One was incubated for 7 days and the other for 14 days. Gastrointestinal nematode larvae were recovered from each culture and counted. Percentage of larval development reduction was determined using a ratio of larvae/eggs deposited in the control and treated groups. Duddingtonia flagrans survived the digestive process of goats, and maintained its predatory activity, being observed from 21 to 81 h PI (3 to 4 days). A reduction in the infective larvae population in the treated group compared to the non-treated group was observed in both incubation periods (7 days: 5.3-36.0%; 14 days: 0-52.8%, P>0.05). Although a single inoculation of D. flagrans can induce a reduction of infective larvae collected from faeces, a different scheme of dosing may be needed to enhance the efficacy of D. flagrans in goats.

Microcalorimetric studies on metabolic and germination response to temperature for three populations of winterfat (Eurotia lanata)

Treesearch

Tonya Thygerson; D. Terrance Booth; Jennifer M. Harris; Lee D. Hansen; Bruce N. Smith

2001-01-01

Eurotia lanata (Pursh) Moq. (winterfat) is a boreal cold-desert subshrub, seldom more than 2 feet tall, that thrives in dry climates at cool temperatures. Diaspore collections from Matador, Saskatchewan, Canada; Pine Bluffs, Wyoming; and Sterling, Colorado, were cleaned and placed on moistened filter paper in petri dishes maintained at 0, 5, 10, 15, and 20 °C to study...

Desorption of SVOCs from Heated Surfaces in the Form of Ultrafine Particles.

PubMed

Wallace, Lance A; Ott, Wayne R; Weschler, Charles J; Lai, Alvin C K

2017-02-07

Ultrafine particles (UFP) produced by electric heating of stoves and metal cooking pans, absent food, have been hypothesized to be created from a surface film of semivolatile organic compounds (SVOCs) sorbed from the surrounding air. This study tests that hypothesis by size-resolved measurements extending the lower range of the UFP studied from 10 to 2.3 nm, and including other surfaces (glass, aluminum, and porcelain). Heating glass Petri dishes or squares of aluminum foil to about 350-400 °C for 4-6 min removed all sorbed organic substances completely. Subsequent exposure of these "clean" Petri dishes and foil squares to indoor air in two different residences for successively longer periods (1 h to 281 days), followed by heating the materials for 4-6 min, indicated a strong relationship of the number, size distribution, and mass of the UFP to the time exposed. Estimates of the accumulation rate of SVOCs on surfaces were similar to those in studies of organic film buildup on indoor windows. Transfer of skin oils by touching the glass or foil surfaces, or after washing the glass surface with detergent and bare hands, was also observed, with measured particle production comparable with that produced by long-term exposure to indoor air.

Comparative rice seed toxicity tests using filter paper, growth pouch-tm, and seed tray methods

USGS Publications Warehouse

Wang, W.

1993-01-01

Paper substrate, especially circular filter paper placed inside a Petri dish, has long been used for the plant seed toxicity test (PSTT). Although this method is simple and inexpensive, recent evidence indicates that it gives results that are significantly different from those obtained using a method that does not involve paper, especially when testing metal cations. The study compared PSTT using three methods: filter paper, Growth Pouch-TM, and seed tray. The Growth Pouch-TM is a commercially available device. The seed tray is a newly designed plastic receptacle placed inside a Petri dish. The results of the Growth Pouch-TM method showed no toxic effects on rice for Ag up to 40 mg L-1 and Cd up to 20 mg L-1. Using the seed tray method, IC50 (50% inhibitory effect concentration) values were 0.55 and 1.4 mg L-1 for Ag and Cd, respectively. Although results of filter paper and seed tray methods were nearly identical for NaF, Cr(VI), and phenol, the toxicities of cations Ag and Cd were reduced by using the filter paper method; IC50 values were 22 and 18 mg L-1, respectively. The results clearly indicate that paper substrate is not advisable for PSTT.

Singlet oxygen luminescence kinetics under PDI relevant conditions of pathogenic dermatophytes and molds.

PubMed

Bornhütter, Tobias; Shamali, Nedaa; Saltsman, Irena; Mahammed, Atif; Gross, Zeev; Däschlein, Georg; Röder, Beate

2018-01-01

A treatment of onychomycosis using the photodynamic effect would be a favorable alternative to currently used antimycotic drugs. This study should be considered as a first step towards development and control of an efficient photodynamic inactivation of onychomycosis causative pathogens. Here, we evaluate the usage of time-resolved 2D singlet oxygen luminescence detection in combination with 2D fluorescence scanning as a tool to understand the behavior of the photosensitizer when applied to fungi on Petri dishes. To investigate the interaction of photosensitizer with fungi in various concentrations and in different stages of live, a photodynamic inactivation was avoided by keeping the samples in darkness. Scans of singlet oxygen luminescence and photosensitizer fluorescence were performed over a period of 24days. Two different photosensitizer, a cationic porphyrin and cationic corrole and two fungi strains, the dermatophyte Trichophyton rubrum and the mold Scopulariopsis brevicaulis, were investigated in this study. The two-dimensional correlation of photosensitizer fluorescence and singlet oxygen luminescence revealed differences in the diffusion of both photosensitizer. Even though the singlet oxygen luminescence was quenched with increasing growth of fungi, it was found that the kinetics of singlet oxygen luminescence could be detected on Petri dishes for both photosensitizers and both fungi strains for up to seven days. Copyright © 2017 Elsevier B.V. All rights reserved.

Larvicidal effects of mineral turpentine, low aromatic white spirits, aqueous extracts of Cassia alata, and aqueous extracts, ethanolic extracts and essential oil of betel leaf (Piper betle) on Chrysomya megacephala.

PubMed

Kumarasinghe, Sujith Prasad W; Karunaweera, Nadira D; Ihalamulla, Ranjan L; Arambewela, Lakshmi S R; Dissanayake, Roshinie D S C T

2002-12-01

Many methods have been employed, with variable success, in the treatment of cutaneous myiasis caused by Chrysomya species. Experiment 1: to assess the larvicidal effect of mineral turpentine (MT) and the main ingredient of MT, low aromatic white spirits (LAWS), on Chrysomya megacephala larvae in vitro. Experiment 2: to assess the larvicidal effects of aqueous extracts of winged senna (Cassia alata), and aqueous extracts, ethanolic extracts and essential oil of betel leaf (Piper betle). In experiment 1, two samples of LAWS were obtained from two industrialists (samples 1 and 2). Adult flies of C. megacephala were bred in the insectory of the Department of Parasitology, Faculty of Medicine, University of Colombo. Petri dishes were prepared with pads of cotton wool. These cotton pads were soaked separately in MT, LAWS samples 1 and 2, and normal saline as a control. Ten larvae were placed in each Petri dish. The activity of the larvae was observed and recorded half-hourly. MT and the two samples of LAWS were analyzed by chromatography. In experiment 2, volatile essential oil of betel was prepared using a standard steam distillation process. An ethanolic extract of betel was obtained after boiling the crushed leaf with water, and mixing the stock with ethanol. Betel oil dilutions of 1-4% were prepared using 1% Tween 80 (v/v aq) as a solvent, with 0.05 g/100 mL sodium lauryl sulphate (as stabilizer) and 0.01 g/100 mL methyl paraben (as a preservative). Cotton wool swabs soaked in 1, 2, 3 and 4% essential oil of betel in 1% Tween 80 (v/v aq) prepared as above, 1, 2, 3 and 4% ethanolic extract of betel, 50 and 25% aqueous extract of C. alata, and 50 and 25% aqueous extract of betel were placed in separate Petri dishes. Ten larvae were placed in each Petri dish. 1% Tween 80 solvent with the stabilizer and the preservative, but without betel essential oil, was used as a negative control and MT was used as a positive control. Larval motility was assessed as before. MT and the two LAWS samples killed the larvae in vitro within 4 h. Chromatography showed more unidentified constituents in MT than in pure LAWS, indicating additional substances in MT. The 4 and 3% preparations of the essential oil of betel were effective in killing 100% of the larvae of Chrysomya within 3 h 30 min. The 2% extract of betel essential oil killed 96.7% of larvae in 4 h. Ethanolic and aqueous extracts of betel, the aqueous extract of C. alata, normal saline and the Tween 80 solvent were not larvicidal. MT and LAWS, the main ingredient of MT, were effective in killing Chrysomya larvae. Essential oil obtained from betel leaves also showed a dose-dependent larvicidal effect on Chrysomya larvae. This natural product may be effective in the treatment of wound myiasis.

A Video-Tracking Analysis-Based Behavioral Assay for Larvae of Anopheles pseudopunctipennis and Aedes aegypti (Diptera: Culicidae).

PubMed

Gonzalez, Paula V; Alvarez Costa, Agustín; Masuh, Héctor M

2017-05-01

Aedes aegypti (L.) is the primary vector of dengue, yellow fever, Zika, and chikungunya viruses, whereas Anopheles pseudopunctipennis (Theobald) is the principal vector for malaria in Latin America. The larval stage of these mosquitoes occurs in very different development habitats, and the study of their respective behaviors could give us valuable information to improve larval control. The aim of this study was to set up a bioassay to study basic larval behaviors using a video-tracking software. Larvae of An. pseudopunctipennis came from two localities in Salta Province, Argentina, while Ae. aegypti larvae were of the Rockefeller laboratory strain. Behaviors of individual fourth-instar larvae were documented in an experimental petri dish arena using EthoVision XT10.1 video-tracking software. The overall level of movement of larval An. pseudopunctipennis was lower than that for Ae. aegypti, and, while moving, larval An. pseudopunctipennis spent significantly more time swimming near the wall of the arena (thigmotaxis). This is the first study that analyzes the behavior of An. pseudopunctipennis larvae. The experimental system described here may be useful for future studies on the effect of physiological, toxicological, and chemosensory stimuli on larval behaviors. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Interfacing Lab-on-a-Chip Embryo Technology with High-Definition Imaging Cytometry.

PubMed

Zhu, Feng; Hall, Christopher J; Crosier, Philip S; Wlodkowic, Donald

2015-08-01

To spearhead deployment of zebrafish embryo biotests in large-scale drug discovery studies, automated platforms are needed to integrate embryo in-test positioning and immobilization (suitable for high-content imaging) with fluidic modules for continuous drug and medium delivery under microperfusion to developing embryos. In this work, we present an innovative design of a high-throughput three-dimensional (3D) microfluidic chip-based device for automated immobilization and culture and time-lapse imaging of developing zebrafish embryos under continuous microperfusion. The 3D Lab-on-a-Chip array was fabricated in poly(methyl methacrylate) (PMMA) transparent thermoplastic using infrared laser micromachining, while the off-chip interfaces were fabricated using additive manufacturing processes (fused deposition modelling and stereolithography). The system's design facilitated rapid loading and immobilization of a large number of embryos in predefined clusters of traps during continuous microperfusion of drugs/toxins. It was conceptually designed to seamlessly interface with both upright and inverted fluorescent imaging systems and also to directly interface with conventional microtiter plate readers that accept 96-well plates. Compared with the conventional Petri dish assays, the chip-based bioassay was much more convenient and efficient as only small amounts of drug solutions were required for the whole perfusion system running continuously over 72 h. Embryos were spatially separated in the traps that assisted tracing single embryos, preventing interembryo contamination and improving imaging accessibility.

Intraspecific Signals Inducing Aggregation in Periplaneta americana (Insecta: Dictyoptera).

PubMed

Imen, Saïd; Christian, Malosse; Virginie, Durier; Colette, Rivault

2015-06-01

Chemical communication is necessary to induce aggregation and to maintain the cohesion of aggregates in Periplaneta americana (L.) cockroaches. We aimed to identify the chemical message inducing aggregation in this species. Two types of bioassays were used-binary choice tests in Petri dishes and tests in Y-olfactometer. Papers conditioned by direct contact of conspecifics induce aggregation when proposed in binary choice tests and were attractive in a Y-olfactometer. The identification of the molecules present on these conditioned papers indicated that dichloromethane extracts contained mainly cuticular hydrocarbons whereas methanol extracts contained more volatile molecules. Only a mixture of extracts in both solvents induced aggregation. High concentrations of cuticular hydrocarbons are necessary to induce aggregation when presented alone. When presented with volatile molecules present in methanol extracts, low concentrations of cuticular hydrocarbons are sufficient to induce aggregation if they are presented in contact. Among volatile molecules collected on filter paper, a mixture of three compounds-hexadecanoic acid, pentadecanoic acid, and pentaethylene glycol-induced aggregation. Our results provide evidence that aggregation processes in P. americana relies on a dual mechanism: attraction over long distances by three volatile molecules and maintenance on site by contact with cuticular hydrocarbons. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Investigation of Immunoregulatory Alphaglobulin (IRA) in Shock and Trauma.

DTIC Science & Technology

1980-07-01

rice whose limbs were amputated 2 days earlier Were fraction by adherence to glass Petri dishes or nylon wool columns (2 cycl,7), or by treatin Wi...to alloantigens. suggesting the presence of suppressor cells. The suppressor cells were found to adhere to glass and to nylon wool columns. They were...negative cell population capable of adhering to glass and nylon wool, Presumably macrophages. was responsible for inhibiting the response of lymphocytes

Ki-67 Expression in Human Tumors Measured by Flow Cytometry

DTIC Science & Technology

1990-01-01

Analyzed Fresh tissues obtained from the lymph node biopsies of 30 patients diagnosed as having non-Hodgkin’s lymphoma, nine biopsies identified as...breast tumors, and eight biopsies identified as colon tumors were included in this study. Cell Lines K562 Cell Line The human ervthroleukemia cell line...petri dish. While holding the tissue with toothed forceps , it wa,-is minced with scissors. Ujsing at transfer pip:., tissue fragments we re aspirated

Dissociation of Hexavalent Chromium from Sanded Paint Particles into a Simulated Lung Fluid

DTIC Science & Technology

2006-06-01

was simulated with a porcine based mucin . Sanded particles were collected based on particle size into the impactor’s six petri dishes, which...was used to imitate particle deposition onto a layer of lung fluid. The lung fluid was simulated with a porcine based mucin . Sanded particles were...documented as those directly related to corrosion control such as maintenance, repair, treatment , washing, painting, depainting, and sealing. These

Allelopathic assessment of selected common weeds in Malaysia

NASA Astrophysics Data System (ADS)

Nurul Ain, M. B.; Nornasuha, Y.; Ismail, B. S.

2016-11-01

A laboratory study was conducted to evaluate the allelopathic potential of eight common weed species in Malaysia, namely, Ageratum conyzoides, Tridax procumbens, Cyperus iria, Fimbristylis miliacea, Eleusine indica, Imperata cylindrica, Lygodium flexuosum and Nephrolepis biserrata of different morphological characteristics (broadleaves, sedges, grasses and ferns). The allelopathic study of these weeds was carried out by testing the leaf litter leachate through the Sandwich method and the volatile compounds of these weeds through the Dish pack method with three replicates for each donor species. The results obtained from both methods were statistically analyzed and the means had converted to percentage growth inhibition to determine the inhibition pattern on the radicle and hypocotyl growth of lettuce seedlings. Among the eight weed species tested, Ageratum conyzoides showed the strongest growth inhibition on lettuce radicle elongation (86%) in the sandwich bioassay compared to the control, followed by Tridax procumbens (71%), which both species being broadleaves weeds. In the dish pack bioassay Lygodium flexuosum (fern) demonstrated maximum inhibition on the growth the radicle and hypocotyl for each different distance from the source well. On the other hand, two weed species exhibited enhanced on the growth radicle and hypocotyl when compared to that of the control in dish pack bioassay. Nephrolepis biserrata and Fimbristylis miliacea were the species that showed the highest growth stimulatory effect. The results presented can be utilized as benchmark information for further research on the elucidation of leachates and volatile chemicals involved in allelopathy in nature. The information can also be helpful in the development of new bioactive chemicals from natural products in weed control strategies.

Chemical composition, antifeedant, repellent, and toxicity activities of the rhizomes of galangal, Alpinia galanga against Asian subterranean termites, Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae).

PubMed

Abdullah, Fauziah; Subramanian, Partiban; Ibrahim, Halijah; Abdul Malek, Sri Nurestri; Lee, Guan Serm; Hong, Sok Lai

2015-01-01

Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Chemical Composition, Antifeedant, Repellent, and Toxicity Activities of the Rhizomes of Galangal, Alpinia galanga Against Asian Subterranean Termites, Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae)

PubMed Central

Abdullah, Fauziah; Subramanian, Partiban; Ibrahim, Halijah; Abdul Malek, Sri Nurestri; Lee, Guan Serm; Hong, Sok Lai

2015-01-01

Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices. PMID:25688085

The effects of hydroxy fatty acids on the hyphal branching of germinated spores of AM fungi.

PubMed

Nagahashi, Gerald; Douds, David D

2011-01-01

Two hydroxy fatty acids, tentatively identified previously in carrot root exudates, were tested for their effects on hyphal growth of the arbuscular mycorrhizal (AM) fungus, Gigaspora gigantea (Nicol. and Gerd.) Gerdemann and Trappe. Best results were achieved with a long-term bioassay (7-8d) with nanomolar concentrations throughout the Petri dish in contrast to the rapid microinjection bioassay (16-24h) in which nanogram quantities were injected near growing hyphal tips. When 5nM 2-hydroxy fatty acids of various chain length were tested, the length of the hydroxyl fatty acid was significant since only 2-hydroxytetradecanoic acid (2OH-TDA) and to a slightly lesser degree, 2-hydroxydodecanoic acid (2OH-DDA) induced a hyphal growth response while 2-hydroxydecanoic acid (2OH-DA) and 2-hydroxyhexadecanoic (2OH-HDA) acid did not. The position of the hydroxyl group was critical since 5nM 3-hydroxytetradecanoic acid (3OH-TDA) had no effect on hyphal growth. The length of the non-hydroxy containing straight chain fatty acid, per se, did not appear significant since none of these fatty acids had an effect on hyphal growth. The morphological growth response promoted by 2OH-TDA consisted of multiple lateral branches, spaced fairly regularly apart, along the primary germ tubes as well as some lateral branch formation off the major secondary hyphae. This growth response was identical to that observed when germinated spores were allowed to grow towards cultured carrot roots in vitro. This response to 2OH-TDA also was observed with an unidentified Gigaspora species but no morphological response was observed with Glomus intraradices Schenck and Smith. The results indicate that 2-hydroxy fatty acids are another putative category of root exudate signals perceived by Gigaspora species, stimulating an increase in elongated lateral branches. Published by Elsevier Ltd.

Measuring effects of music, noise, and healing energy using a seed germination bioassay.

PubMed

Creath, Katherine; Schwartz, Gary E

2004-02-01

To measure biologic effects of music, noise, and healing energy without human preferences or placebo effects using seed germination as an objective biomarker. A series of five experiments were performed utilizing okra and zucchini seeds germinated in acoustically shielded, thermally insulated, dark, humid growth chambers. Conditions compared were an untreated control, musical sound, pink noise, and healing energy. Healing energy was administered for 15-20 minutes every 12 hours with the intention that the treated seeds would germinate faster than the untreated seeds. The objective marker was the number of seeds sprouted out of groups of 25 seeds counted at 12-hour intervals over a 72-hour growing period. Temperature and relative humidity were monitored every 15 minutes inside the seed germination containers. A total of 14 trials were run testing a total of 4600 seeds. Musical sound had a highly statistically significant effect on the number of seeds sprouted compared to the untreated control over all five experiments for the main condition (p < 0.002) and over time (p < 0.000002). This effect was independent of temperature, seed type, position in room, specific petri dish, and person doing the scoring. Musical sound had a significant effect compared to noise and an untreated control as a function of time (p < 0.03) while there was no significant difference between seeds exposed to noise and an untreated control. Healing energy also had a significant effect compared to an untreated control (main condition, p < 0.0006) and over time (p < 0.0001) with a magnitude of effect comparable to that of musical sound. This study suggests that sound vibrations (music and noise) as well as biofields (bioelectromagnetic and healing intention) both directly affect living biologic systems, and that a seed germination bioassay has the sensitivity to enable detection of effects caused by various applied energetic conditions.

A pipette-based calibration system for fast-scan cyclic voltammetry with fast response times.

PubMed

Ramsson, Eric S

2016-01-01

Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that utilizes the oxidation and/or reduction of an analyte of interest to infer rapid changes in concentrations. In order to calibrate the resulting oxidative or reductive current, known concentrations of an analyte must be introduced under controlled settings. Here, I describe a simple and cost-effective method, using a Petri dish and pipettes, for the calibration of carbon fiber microelectrodes (CFMs) using FSCV.

Ignition of Liquid Fuel Spray and Simulated Solid Rocket Fuel by Photoignition of Carbon Nanotube Utilizing a Camera Flash

DTIC Science & Technology

2011-12-01

10,11 There has been a recent report on the photoignition of graphene oxide for fuel ignition applications.12 In this report, we will describe the...slide Aluminum foil Glass petri dish Xe flash Camera Sample Black spray paint Figure 2- Schematic and photographs of the experimental setup...Gilje, Sergey Dubin, Alireza Badakhshan, Jabari Farrar, Stephen. A. Danczyk, Richard B. Kaner, “Photothermal Deoxygenation of Graphene Oxide for

Adaptation of plastic surfaces for tissue culture by glow discharge.

PubMed Central

Amstein, C F; Hartman, P A

1975-01-01

Plastic petri dishes and microtitration plates were electrically charged by a glow discharge unit installed in a vacuum evaporator. Charged and uncharged plates, as well as plates commercially treated for tissue culture, were inoculated with Vero and BHK-21 cell lines; secondary cultures of monkey kidney, chicken lung, canine kidney, and embryonic bovine kidney; and primary chicken embryo fibroblasts and chicken lung cells. All cell cultures grew normally on petri plates charged with the covers open. Growth rate and cell density compared favorably with growth on the commercial tissue culture plates; cell growth was somewhat less dense, however, on plates charged with the covers closed. Charged plates could be sterilized by ultraviolet light and ethylene oxide with no adverse effects on cell growth. Cells inoculated onto plates charged up to 7 months before inoculation grew as well as on freshly charged plates. Images PMID:818106

Role of Stat3 and ErbB2 in Breast Cancer

DTIC Science & Technology

2013-12-01

required for cell motility, through the formation of lamellipodia at the leading edge of cells in a wound healing assay29. Since cadherin-11 leads...cells in medium lacking the inhibitor. 2.2. Wound healing assay Cells were plated in 3 cm tissue culture petri dishes in DMEM/10% fetal calf serum...solve this apparent paradox,we examined the ability of IL6 it- self , whose synthesis is induced upon cadherin engagement and is the trigger of Stat3

AFRRI (Armed Forces Radiobiology Research Institute) Reports, July, August and September 1987.

DTIC Science & Technology

1987-11-01

mononuclear cell layer obtained after Percol isolation contained approximately 90% mono- cytes as assessed by esterase staining. In most experiments...forming cell) were assayed using the double layer agar technique basically as described by Hagan et al. (22). The culture medium was double strength CMRL...trypticase soy broth, 20 g/ml L-asparagine. and penicillin-streptomycin. In the bottom layer of 35 mm plastic Petri dishes was 1 ml of a 1:1 mixture of culture

Microgravity Effects on the Early Events of Biological Nitrogen Fixation in Medicago Truncatula: Results from the SyNRGE Experiment

NASA Technical Reports Server (NTRS)

Stutte, Gary W.; Roberts, Michael

2012-01-01

SyNRGE (Symbiotic Nodulation in a Reduced Gravity Environment) was a sortie mission on STS-135 in the Biological Research in Canisters (BRIC) hardware to study the effect of microgravity on a plant-microbe symbiosis resulting in biological nitrogen fixation. Medicago truncatula, a model species for th legume family, was inoculated with its bacterial symbiont, Sinorhizobium meliloti, to observe early biomolecular events associated with infection and nodulation in Petri Dish Fixation Units (PDFU's).

Biological Research in Canisters (BRIC) - Light Emitting Diode (LED)

NASA Technical Reports Server (NTRS)

Levine, Howard G.; Caron, Allison

2016-01-01

The Biological Research in Canisters - LED (BRIC-LED) is a biological research system that is being designed to complement the capabilities of the existing BRIC-Petri Dish Fixation Unit (PDFU) for the Space Life and Physical Sciences (SLPS) Program. A diverse range of organisms can be supported, including plant seedlings, callus cultures, Caenorhabditis elegans, microbes, and others. In the event of a launch scrub, the entire assembly can be replaced with an identical back-up unit containing freshly loaded specimens.

Efficacy of heat treatment for disinfestation of concrete grain silos.

PubMed

Opit, G P; Arthur, F H; Bonjour, E L; Jones, C L; Phillips, T W

2011-08-01

Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50 degrees C for at least 6 h. Ventilated plastic containers with a capacity of 100 g of wheat, Triticum aestivum L., held Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Polyvinyl chloride containers with a capacity of 300 g of wheat held adults of Liposcelis corrodens (Heymons) (Psocoptera: Liposcelididae) and Liposcelis decolor (Pearman), which were contained in 35-mm Petri dishes within the grain. Containers were fastened to a rope suspended from the top of the silo at depths of 0 m (just under the top manhole), 10 m, 20 m, and 30 m (silo floor). When the highest temperature achieved was approximately 50 degrees C for 6 h, parental mortality ofR. dominica and T. castaneum, and both psocid species was 98-100%. Progeny production of R. dominica occurred when there was parental survival, but in general R. dominica seemed less impacted by the heat treatment than T. castaneum. There was 100% mortality of L. corrodens at all depths in the heat treatments but only 92.5% mortality for L. decolor, with most survivors located in the bioassay containers at the top of the silo. Results show wheat kernels may have an insulating effect and heat treatment might be more effective when used in conjunction with sanitation and cleaning procedures.

SU-G-TeP3-02: Determination of Geometry-Specific Backscatter Factors for Radiobiology Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viscariello, N; Culberson, W; Lawless, M

2016-06-15

Purpose: Radiation biology research relies on an accurate radiation dose delivered to the biological target. Large field irradiations in a cabinet irradiator may use the AAPM TG-61 protocol. This relies on an air-kerma measurement and conversion to absorbed dose to water (Dw) on the surface of a water phantom using provided backscatter factors. Cell or small animal studies differ significantly from this reference geometry. This study aims to determine the impact of the lack of full scatter conditions in four representative geometries that may be used in radiobiology studies. Methods: MCNP6 was used to model the Dw on the surfacemore » of a full scatter phantom in a validated orthovoltage x-ray reference beam. Dw in a cylindrical mouse, 100 mm Petri dish, 6-well and 96-well cell culture dishes was simulated and compared to this full scatter geometry. A reference dose rate was measured using the TG-61 protocol in a cabinet irradiator. This nominal dose rate was used to irradiate TLDs in each phantom to a given dose. Doses were obtained based on TLDs calibrated in a NIST-traceable beam. Results: Compared to the full scattering conditions, the simulated dose to water in the representative geometries were found to be underestimated by 12-26%. The discrepancy was smallest with the cylindrical mouse geometry, which most closely approximates adequate lateral- and backscatter. TLDs irradiated in the mouse and petri dish phantoms using the TG-61 determined dose rate showed similarly lower values of Dw. When corrected for this discrepancy, they agreed with the predicted Dw within 5%. Conclusion: Using the TG-61 in-air protocol and given backscatter factors to determine a reference dose rate in a biological irradiator may not be appropriate given the difference in scattering conditions between irradiation and calibration. Without accounting for this, the dose rate is overestimated and is dependent on irradiation geometry.« less

A simple lead dust fall method predicts children's blood lead level: New evidence from Australia.

PubMed

Gulson, Brian; Taylor, Alan

2017-11-01

We have measured dust fall accumulation in petri dishes (PDD) collected 6 monthly from inside residences in Sydney urban area, New South Wales, Australia as part of a 5-year longitudinal study to determine environmental associations, including soil. with blood lead (PbB) levels. The Pb loading in the dishes (n = 706) had geometric means (GM) of 24µg/m 2 /30d, a median value of 22µg/m 2 /30d with a range from 0.2 to 11,390µg/m 2 /30d. Observed geometric mean PbB was 2.4µg/dL at ages 2-3 years. Regression analyses showed a statistically significant relationship between predicted PbB and PDD. The predicted PbB values from dust in our study are consistent with similar analyses from the US in which floor dust was collected by wipes. Predicted PbB values from PDD indicate that an increase in PDD of about 100µg/m 2 /30d would increase PbB by about 1.5µg/dL or a doubling PbB at the low levels currently observed in many countries. Predicted PbB values from soil indicate that a change from 0 to 1000mg Pb/kg results in an increase of 1.7µg/dL in PbB, consistent with earlier investigations. Blood Pb levels can be predicted from dust fall accumulation (and soil) in cases where blood sampling is not always possible, especially in young children. Petri dish loading data could provide an alternative or complementary "action level" at about 100µg Pb/m 2 /30 days, similar to the suggested level of about 110µg Pb/m 2 for surface wipes, for use in monitoring activities such as housing rehabilitation, demolition or soil resuspension. Copyright © 2017 Elsevier Inc. All rights reserved.

BRIC-100VC Biological Research in Canisters (BRIC)-100VC

NASA Technical Reports Server (NTRS)

Richards, Stephanie E.; Levine, Howard G. (Compiler); Romero, Vergel

2016-01-01

The Biological Research in Canisters (BRIC) is an anodized-aluminum cylinder used to provide passive stowage for investigations of the effects of space flight on small specimens. The BRIC 100 mm petri dish vacuum containment unit (BRIC-100VC) has supported Dugesia japonica (flatworm) within spring under normal atmospheric conditions for 29 days in space and Hemerocallis lilioasphodelus L. (daylily) somatic embryo development within a 5% CO2 gaseous environment for 4.5 months in space. BRIC-100VC is a completely sealed, anodized-aluminum cylinder (Fig. 1) providing containment and structural support of the experimental specimens. The top and bottom lids of the canister include rapid disconnect valves for filling the canister with selected gases. These specialized valves allow for specific atmospheric containment within the canister, providing a gaseous environment defined by the investigator. Additionally, the top lid has been designed with a toggle latch and O-ring assembly allowing for prompt sealing and removal of the lid. The outside dimensions of the BRIC-100VC canisters are 16.0 cm (height) x 11.4 cm (outside diameter). The lower portion of the canister has been equipped with sufficient storage space for passive temperature and relative humidity data loggers. The BRIC- 100VC canister has been optimized to accommodate standard 100 mm laboratory petri dishes or 50 mL conical tubes. Depending on storage orientation, up to 6 or 9 canisters have been flown within an International Space Station (ISS) stowage locker.

Early development of fern gametophytes in microgravity

NASA Technical Reports Server (NTRS)

Roux, Stanley J.; Chatterjee, Ani; Hillier, Sheila; Cannon, Tom

2003-01-01

Dormant spores of the fern Ceratopteris richardii were flown on Shuttle mission STS-93 to evaluate the effects of micro-g on their development and on their pattern of gene expression. Prior to flight the spores were sterilized and sown into one of two environments: (1) Microscope slides in a video-microscopy module; and (2) Petri dishes. All spores were then stored in darkness until use. Spore germination was initiated on orbit after exposure to light. For the spores on microscope slides, cell level changes were recorded through the clear spore coat of the spores by video microscopy. After their exposure to light, spores in petri dishes were frozen in orbit at four different time points during which on earth gravity fixes the polarity of their development. Spores were then stored frozen in Biological Research in Canister units until recovery on earth. The RNAs from these cells and from 1-g control cells were extracted and analyzed on earth after flight to assay changes in gene expression. Video microscopy results revealed that the germinated spores developed normally in microgravity, although the polarity of their development, which is guided by gravity on earth, was random in space. Differential Display-PCR analyses of RNA extracted from space-flown cells showed that there was about a 5% change in the pattern of gene expression between cells developing in micro-g compared to those developing on earth. c2002 Published by Elsevier Science Ltd on behalf of COSPAR.

Effect of weightlessness conditions on the somatic embryogenesis in the culture of carrot cells

NASA Technical Reports Server (NTRS)

Butenko, R. G.; Dmitriyeva, N. N.; Ongko, V.; Basyrova, L. V.

1977-01-01

A carrot cell culture seeded in Petri dishes in the United States and transported to the USSR was subjected to weightlessness for 20 days during the flight of Kosmos 782. The controls were cultures placed on a centrifuge (1 g) inside the satellite and cultures left on ground in the U.S.S.R. and the United States. A count of structures in the dishes after the flight showed that the number of developing embryonic structures and the extent of their differentiation in weightlessness did not reliably differ from the number and extent of differentiation in structures developed on the ground. Structures with long roots developed in weightlessness. Analysis of the root zones showed that these roots differed by the increased size of the zone of differentiated cells. The increased size of the zones of differentiated cells can indicate earlier development of embryonic structures.

Portable Fiber Laser System and Method to Remove Pits and Cracks on Sensitized Surfaces of Aluminum Alloys

DTIC Science & Technology

2015-08-01

resistant 5083- H116 aluminum, sheet, 1/4" thick, 2" x 24", 2 pieces 71.60 5 Reagent VWR & Fisher Nitric acid and sodium hydroxide for mass loss...Temperature stability ±0.1oC @37oC Temperature uniformity ±0.2oC @37oC 693.55 4 5083-H116 Al-Mg alloy materials McMaster Carr Strengthened corrosion ...test, other acids for etching, electrochemical polishing, and anodizing 700.28 6 Containers VWR Beakers, petri dishes, bottles, graduated cylinders

Culture without the petri-dish.

PubMed

Thompson, Jeremy G

2007-01-01

Automation of oocyte maturation and embryo production techniques is a new and exciting development in the field of reproductive technologies. There are two areas where increased automation is having an impact: in the area of embryo diagnostics and in the process of embryo production itself. Benefits include decreased staffing and skill requirements for production and assessment of embryos, as well as increasing quality management systems by removing the "human" factor. However, the uptake of new technologies is likely to be slow, as costs and the conservative nature of the Assisted Reproduction Technology industry to adopt new techniques.

Practical direct plaque assay for coliphages in 100-ml samples of drinking water.

PubMed Central

Grabow, W O; Coubrough, P

1986-01-01

A practical single-agar-layer plaque assay for the direct detection of coliphages in 100-ml samples of water was designed and evaluated. With this assay a 100-ml sample of water, an agar medium containing divalent cations, and the host Escherichia coli C (ATCC 13706) were mixed in a single container, and the mixture was plated on 10 14-cm-diameter petri dishes. It was more sensitive, reliable, and accurate than various other methods and proved rapid, simple, and economic. PMID:3532952

The dizzying material evolution of the toothbrush

NASA Astrophysics Data System (ADS)

Salveson, Paul

The toothbrush has evolved a highly specialized material aura over the last 150 years in the petri dish of capitalism. It has been bred to appear cutting edge to the culturally trained eye, much like the bird of paradise has developed beautiful ornate plumage to attract a mate. As the toothbrush's formal evolution becomes more detailed and specific, the transparency of its purpose becomes increasingly convoluted and easily detached from its material reality. An alien object is slowly emerging from a complex set of cultural conditions. It lives in our houses and cleans our teeth.

Quantification of Vibrio species in oysters from the Gulf of Mexico with two procedures based on MPN and PCR.

PubMed

Barrera-Escorcia, Guadalupe; Wong-Chang, Irma; Fernández-Rendón, Carlos Leopoldo; Botello, Alfonso Vázquez; Gómez-Gil, Bruno; Lizárraga-Partida, Marcial Leonardo

2016-11-01

Oysters can accumulate potentially pathogenic water bacteria. The objective of this study was to compare two procedures to quantify Vibrio species present in oysters to determine the most sensitive method. We analyzed oyster samples from the Gulf of Mexico, commercialized in Mexico City. The samples were inoculated in tubes with alkaline peptone water (APW), based on three tubes and four dilutions (10 -1 to 10 -4 ). From these tubes, the first quantification of Vibrio species was performed (most probable number (MPN) from tubes) and bacteria were inoculated by streaking on thiosulfate-citrate-bile salts-sucrose (TCBS) petri dishes. Colonies were isolated for a second quantification (MPN from dishes). Polymerase chain reaction (PCR) was used to determine species with specific primers: ompW for Vibrio cholerae, tlh for Vibrio parahaemolyticus, and VvhA for Vibrio vulnificus. Simultaneously, the sanitary quality of oysters was determined. The quantification of V. parahaemolyticus was significantly higher in APW tubes than in TCBS dishes. Regarding V. vulnificus counts, the differences among both approaches were not significant. In contrast, the MPNs of V. cholerae obtained from dishes were higher than from tubes. The quantification of MPNs through PCR of V. parahaemolyticus and V. vulnificus obtained from APW was sensitive and recommendable for the detection of both species. In contrast, to quantify V. cholerae, it was necessary to isolate colonies on TCBS prior PCR. Culturing in APW at 42 °C could be an alternative to avoid colony isolation. The MPNs of V. cholerae from dishes was associated with the bad sanitary quality of the samples.

Isolation of amylolytic, xylanolytic, and cellulolytic microorganisms extracted from the gut of the termite Reticulitermes santonensis by means of a micro-aerobic atmosphere.

PubMed

Tarayre, Cédric; Brognaux, Alison; Bauwens, Julien; Brasseur, Catherine; Mattéotti, Christel; Millet, Catherine; Destain, Jacqueline; Vandenbol, Micheline; Portetelle, Daniel; De Pauw, Edwin; Eric, Haubruge; Francis, Frédéric; Thonart, Philippe

2014-05-01

The aim of this work was to isolate enzyme-producing microorganisms from the tract of the termite Reticulitermes santonensis. The microorganisms were extracted from the guts and anaerobic (CO₂ or CO₂/H₂) and micro-aerobic atmospheres were used to stimulate growth. Three different strategies were tried out. First, the sample was spread on Petri dishes containing solid media with carboxymethylcellulose, microcrystalline cellulose or cellobiose. This technique allowed us to isolate two bacteria: Streptomyces sp. strain ABGxAviA1 and Pseudomonas sp. strain ABGxCellA. The second strategy consisted in inoculating a specific liquid medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. The samples were then spread on Petri dishes with the same specific medium containing carboxymethylcellulose, microcrystalline cellulose, or cellobiose. This led to the isolation of the mold Aspergillus sp. strain ABGxAviA2. Finally, the third strategy consisted in heating the first culture and spreading samples on agar plates containing rich medium. This led to the isolation of the bacterium Bacillus subtilis strain ABGx. All those steps were achieved in controlled atmospheres. The four enzyme-producing strains which were isolated were obtained by using a micro-aerobic atmosphere. Later, enzymatic assays were performed on the four strains. Streptomyces sp. strain ABGxAviA1 was found to produce only amylase, while Pseudomonas sp. strain ABGxCellA was found to produce β-glucosidase as well. Aspergillus sp. strain ABGxAviA2 showed β-glucosidase, amylase, cellulase, and xylanase activities. Finally, B. subtilis strain ABGx produced xylanase and amylase.

Candidate nematicidal proteins in a new Pseudomonas veronii isolate identified by its antagonistic properties against Xiphinema index.

PubMed

Canchignia, Hayron; Altimira, Fabiola; Montes, Christian; Sánchez, Evelyn; Tapia, Eduardo; Miccono, María; Espinoza, Daniel; Aguirre, Carlos; Seeger, Michael; Prieto, Humberto

2017-03-17

The nematode Xiphinema index affects grape vines and transmits important viruses associated with fanleaf degeneration. Pseudomonas spp. are an extensive bacterial group in which important biodegradation and/or biocontrol properties can occur for several strains in the group. The aim of this study was to identify new Pseudomonas isolates with antagonist activity against X. index. Forty bacterial isolates were obtained from soil and root samples from Chilean vineyards. Thirteen new fluorescent pseudomonads were found and assessed for their antagonistic capability. The nematicide Pseudomonas protegens CHA0 was used as a control. Challenges of nematode individuals in King's B semi-solid agar Petri dishes facilitated the identification of the Pseudomonas veronii isolate R4, as determined by a 16S rRNA sequence comparison. This isolate was as effective as CHA0 as an antagonist of X. index, although it had a different lethality kinetic. Milk-induced R4 cultures exhibited protease and lipase activities in cell supernatants using both gelatin/tributyrin Petri dish assays and zymograms. Three proteins with these activities were isolated and subjected to mass spectrometry. Amino acid partial sequences enabled the identification of a 49-kDa protease similar to metalloprotease AprA and two lipases of 50 kDa and 69 kDa similar to LipA and ExoU, respectively. Electron microscopy analyses of challenged nematodes revealed degraded cuticle after R4 supernatant treatment. These results represent a new and unexplored property in this species associated with the presence of secretable lipases and protease, similar to characterized enzymes present in biocontrol pseudomonads.

Response of Ceratitis capitata, Bactrocera dorsalis, and Bactrocera cucurbitae (Diptera: Tephritidae) to metabolic stress disinfection and disinfestation treatment.

PubMed

Arévalo-Galarza, Lourdes; Follett, Peter A

2011-02-01

Metabolic stress disinfection and disinfestation (MSDD) is a postharvest treatment designed to control pathogens and arthropod pests on commodities that combines short cycles of low pressure/vacuum and high CO2 with ethanol vapor. Experiments were conducted to evaluate the effect of MSDD treatment on various life stages of Ceratitis capitata (Wiedemann), Mediterranean fruit fly; Bactrocera dorsalis Hendel, oriental fruit fly; and Bactrocera cucurbitae Coquillett, melon fly, in petri dishes and in papaya, Carica papaya L., fruit. In some experiments, the ethanol vapor phase was withheld to separate the effects of the physical (low pressure/ambient pressure cycles) and chemical (ethanol vapor plus low pressure) phases of treatment. In the experiments with tephritid fruit fly larvae and adults in petri dishes, mortality was generally high when insects were exposed to ethanol and low when ethanol was withheld during MSDD treatment, suggesting that ethanol vapor is highly lethal but that fruit flies are quite tolerant of short periods of low pressure treatment alone. When papaya fruit infested with fruit fly eggs or larvae were treated by MSDD, they produced fewer pupae than untreated control fruit, but a substantial number of individuals developed nonetheless. This suggests that internally feeding insects in fruit may be partially protected from the toxic effects of the ethanol because the vapor does not easily penetrate the fruit pericarp and pulp. MSDD treatment using the atmospheric conditions tested has limited potential as a disinfestation treatment for internal-feeding quarantine pests such as fruit flies infesting perishable commodities.

Banana peel culture as an indigenous medium for easy identification of late-sporulation human fungal pathogens.

PubMed

Kindo, A J; Tupaki-Sreepurna, A; Yuvaraj, M

2016-01-01

Fungi are increasing in incidence as human pathogens and newer and rarer species are continuously being encountered. Identifying these species from growth on regular culture media may be challenging due to the absence of typical features. An indigenous and cheap medium, similar to the natural substrate of these fungi, was standardised in our laboratory as an aid to species identification in a conventional laboratory setting. Ripe banana peel pieces, sterilised in an autoclave at 121°C temperature and 15 lbs pressure for 15 min promoted good growth of hyphae and pycnidia or acervuli in coelomycetes, flabelliform and medusoid fruiting bodies of basidiomycetes and fruit bodies such as cleistothecium in ascomycetes. The growth from the primary isolation medium was taken and inoculated onto the pieces of double-autoclaved ripe banana peel pieces in a sterile glass Petri dish with some moisture (sprinkles of sterile distilled water). A few sterile coverslips were placed randomly inside the Petri dish for the growing fungus to stick on to it. The plates were kept at room temperature and left undisturbed for 15-20 days. At a time, one coverslip was taken out and placed on a slide with lactophenol cotton blue and focused under the microscope to look for fruit bodies. Lasiodiplodia theobromae, Macrophomina phaseolina, Nigrospora sphaerica, Chaetomium murorum, Nattrassia mangiferae and Schizophyllum commune were identified by characteristic features from growth on banana peel culture. Banana peel culture is a cheap and effective medium resembling the natural substrate of fungi and is useful for promoting characteristic reproductive structures that aid identification.

Comparative study of the antimutagenic properties of vitamins C and E against mutation induced by norfloxacin

PubMed Central

Alba, Myriam Arriaga; Sánchez, Roberto Rivera; Pérez, Nancy Jannet Ruíz; Navarrete, Jaime Sánchez; Paz, Rocío Flores; Montoya-Estrada, Araceli; Gómez, Juan José Hicks

2008-01-01

Background Norfloxacin like other fluoroquinolones, is known to be mutagenic for Salmonella typhimurium TA102 strain. This mutagenic effect is due to free oxygen radicals (ROS), because it is inhibited by antioxidants such as β-carotene and naturally occurring antioxidants of Roheo discolor and other plants. The aim of this work was to evaluate combination therapy with norfloxacin and vitamins C and E, to reduce the possible genotoxic risk associated with fluoroquinolones. Method The antimutagenicity of α-tocoferol (Vitamin E) and ascorbic acid (Vitamin C) against norfloxacin-induced mutation was evaluated on S. typhimurium TA102, using the aroclor-1254-induced S9 rat liver homogenate. The minimum inhibitory concentration (MIC) a measure of the bactericidal effect of norfloxacin, was obtained in vitro by the plate dilution method. Results Vitamin E (0.5 mg per Petri dish) induced a statistically significant reduction (P < 0.001) in the mutagenicity of norfloxacin, whereas Vitamin C (1 mg per Petri dish) had no such effect. Neither of these vitamins altered the MIC for norfloxacin against 25 uropathogenic strains of Escherichia coli. Conclusion These results suggest that Vitamin E is a potent antimutagen that would be worthwhile being used in conjunction with fluoroquinolone treatment. The minimal antimutagenic effect of Vitamin C observed under these experimental conditions may have been because Vitamin C in the Ames test induces a Fenton reaction, and if divalent cations are present, it can act as a pro-oxidant rather than an antioxidant. Ascorbic acid should be further evaluated in the presence of different divalent cations concentrations. PMID:18267022

Long-term three-dimensional perfusion culture of human adult bone marrow mononuclear cells in bioreactors.

PubMed

Schmelzer, Eva; Finoli, Anthony; Nettleship, Ian; Gerlach, Jörg C

2015-04-01

The construction and long-term maintenance of three-dimensional in vitro bone marrow models is of great interest but still quite challenging. Here we describe the use of a multi-compartment hollow-fiber membrane based three-dimensional perfusion bioreactor for long-term culture of whole human bone marrow mononuclear cells. We also investigated bioreactors with incorporated open-porous foamed hydroxyapatite scaffolds, mimicking the in vivo bone matrix. Cells in bioreactors with and without scaffolds were cultured to 6 weeks and compared to Petri dish controls. Cells were analyzed for gene expression, surface markers by flow cytometry, metabolic activity, hematopoietic potential, viability, and attachment by immunocytochemistry. Cells in bioreactors were metabolic active during long-term culture. The percentages of hematopoietic stem cell and mature endothelial cell fractions were maintained in bioreactors. The expression of most of the analyzed genes stabilized and increased after long-term culture of 6 weeks. Compared to Petri dish culture controls, bioreactor perfusion culture improved in both the short and long-term, the colony formation unit capacity of hematopoietic progenitors. Cells attached to the ample surface area provided by hydroxyapatite scaffolds. The implementation of a hydroxyapatite scaffold did not influence colony formation capacity, percentages of cell type specific fractions, gene expression, cell viability or metabolic turnover when compared to control cells cultured in bioreactors without scaffolds. In conclusion, three-dimensional perfusion bioreactor culture enables long-term maintenance of primary human bone marrow cells, with hydroxyapatite scaffolds providing an in vivo-like scaffold for three-dimensional culture. © 2015 Wiley Periodicals, Inc.

Response of coccinellid larvae to conspecific and heterospecific larval tracks: a mechanism that reduces cannibalism and intraguild predation.

PubMed

Meisner, Matthew H; Harmon, Jason P; Ives, Anthony R

2011-02-01

Cannibalism, where one species feeds on individuals of its own species, and intraguild predation (IGP), where a predator feeds on other predatory species, can both pose significant threats to natural enemies and interfere with their biological control of pests. Behavioral mechanisms to avoid these threats, however, could help maintain superior pest control. Here, we ask whether larvae of Coccinella septempunctata (Coleoptera: Coccinellidae) and Harmonia axyridis (Coleoptera: Coccinellidae) respond to larval tracks deposited by the other and whether this behavioral response reduces the threat of cannibalism and IGP. In petri dish experiments, we show that both H. axyridis and C. septempunctata avoid foraging in areas with conspecific larval tracks. Using a method of preventing larvae from depositing tracks, we then demonstrate that the frequency of cannibalism is greater for both species when larvae are prevented from depositing tracks compared with when the tracks are deposited. For multi-species interactions we show in petri dish experiments that C. septempunctata avoids H. axyridis larval tracks but H. axyridis does not avoid C. septempunctata larval tracks, demonstrating an asymmetry in response to larval tracks that parallels the asymmetry in aggressiveness between these species as intraguild predators. On single plants, we show that the presence of H. axyridis larval tracks reduces the risk of IGP by H. axyridis on C. septempunctata. Our study suggests that larval tracks can be used in more ways than previously described, in this case by changing coccinellid larval behavior in a way that reduces cannibalism and IGP. © 2011 Entomological Society of America

Effects of transgenic Bt rice on growth, reproduction, and superoxide dismutase activity of Folsomia candida (Collembola: Isotomidae) in laboratory studies.

PubMed

Bai, Yaoyu; Yan, Ruihong; Ke, Xin; Ye, Gongyin; Huang, Fangneng; Luo, Yongming; Cheng, Jiaan

2011-12-01

Transgenic rice expressing Bacillus thuringiensis (Bt) CrylAb protein is expected to be commercialized in China in the near future. The use of Bt rice for controlling insect pests sparks intensive debates regarding its biosafety. Folsomia candida is an euedaphic species and is often used as a "standard" test organism in assessing effects of environmental pollutants on soil organisms. In this study, growth, development, reproduction, and superoxide dismutase activity (SOD) of F. candida were investigated in the laboratory for populations reared on leaf tissue or leaf-soil mixtures of two CrylAb rice lines and a non-Bt rice isoline. Two independent tests were performed: 1) a 35-d test using petri dishes containing yeast diet (positive control) or fresh rice leaf tissue, and 2) a 28-d test in soil-litter microcosms containing yeast or a mixture of soil and rice leaf tissue. Biological parameters measured in both tests were number of progeny production, population growth rate, and SOD activity. For the petri dish test, data measured also included insect body length and number of exuviation. There were no significant differences between the populations reared on Bt and non-Bt rice leaf tissue in all measured parameters in both tests and for both Bt rice lines, suggesting no significant effects of the CrylAb protein in Bt rice on F. candida in the laboratory studies. Results of this study should add additional biosafety proofs for use of Bt rice to manage rice pests in China.

Comparative toxicity of leachates from 52 textiles to Daphnia magna.

PubMed

Dave, Göran; Aspegren, Pia

2010-10-01

The environmental aspects of textiles are very complex and include production, processing, transport, usage, and recycling. Textiles are made from a variety of materials and can contain a large number of chemicals. Chemicals are used during production of fibres, for preservation and colouring and they are released during normal wear and during washing. The aim of this study was to investigate the release to water of toxic chemicals from various textiles. Altogether 52 samples of textiles made from cotton (21), linen (4), cotton and linen (7), cellulose (3), synthetic fibres (7), cotton and synthetic fibres (8) and wool (2). Seven were eco-labelled. All textiles were cut into squares and placed into Petri dishes with 50 ml ISO test medium in a concentration series (4-256 cm(2)/50 ml) and tested for acute toxicity to Daphnia magna. Estimated EC50s were converted into weight/volume, and 48-h EC50s ranged between <1 and >182 g/L. It was not possible to detect any difference between fibre type and toxicity (ANOVA), but a significantly higher toxicity was found for printed versus unprinted cotton and cotton/linen textiles, while the opposite was found for synthetic textiles. Eco-labelled products were evenly distributed on a toxicity scale, which means that eco-labelling in its present form does not necessarily protect users or the environment from exposure to toxic chemicals. Therefore, the results from the present study suggest that bioassays and toxicity tests should become an integrated part of textile environmental quality control programs. Copyright © 2010 Elsevier Inc. All rights reserved.

Microbe observation and cultivation array (MOCA) for cultivating and analyzing environmental microbiota.

PubMed

Gao, Weimin; Navarroli, Dena; Naimark, Jared; Zhang, Weiwen; Chao, Shih-Hui; Meldrum, Deirdre R

2013-01-09

The use of culture-independent nucleic acid techniques, such as ribosomal RNA gene cloning library analysis, has unveiled the tremendous microbial diversity that exists in natural environments. In sharp contrast to this great achievement is the current difficulty in cultivating the majority of bacterial species or phylotypes revealed by molecular approaches. Although recent new technologies such as metagenomics and metatranscriptomics can provide more functionality information about the microbial communities, it is still important to develop the capacity to isolate and cultivate individual microbial species or strains in order to gain a better understanding of microbial physiology and to apply isolates for various biotechnological applications. We have developed a new system to cultivate bacteria in an array of droplets. The key component of the system is the microbe observation and cultivation array (MOCA), which consists of a Petri dish that contains an array of droplets as cultivation chambers. MOCA exploits the dominance of surface tension in small amounts of liquid to spontaneously trap cells in well-defined droplets on hydrophilic patterns. During cultivation, the growth of the bacterial cells across the droplet array can be monitored using an automated microscope, which can produce a real-time record of the growth. When bacterial cells grow to a visible microcolony level in the system, they can be transferred using a micropipette for further cultivation or analysis. MOCA is a flexible system that is easy to set up, and provides the sensitivity to monitor growth of single bacterial cells. It is a cost-efficient technical platform for bioassay screening and for cultivation and isolation of bacteria from natural environments.

In vitro repellency of DEET and β-citronellol against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum.

PubMed

Ferreira, Lorena Lopes; Oliveira Filho, Jaires Gomes de; Mascarin, Gabriel Moura; León, Adalberto A Pérez de; Borges, Lígia Miranda Ferreira

2017-05-30

Rhipicephalus sanguineus sensu lato and Amblyomma sculptum can parasite humans and domestic animals and are vectors of pathogens, including zoonoses. Repellents are an important tool of tick control. This study aimed to compare the efficacy of N,N-diethyl- 3-methylbenzamide (DEET), a standard repellent, versus β-citronellol in a Petri dish bioassay. A semicircle of filter paper (31.8cm 2 ) was treated with 87μl of one of four concentrations (0.200, 0.100, 0.050 and 0.025mg/cm 2 ) of β-citronellol, DEET or solvent (ethanol). A head-to-head test was developed treating one side with increasing concentrations of β-citronellol as above mentioned, against the highest concentration of DEET. Besides that a blank assay was performed. Three males and three females were placed in the middle of the plate and their location was evaluated 5, 10 and 30min after the test was initiated. As a result, the time had no significant effect on repellency response of the ticks exposed to both compounds and their concentrations. The repellency response raised according with the increase of concentration. Additionally, our findings indicate that the tick A. sculptum was more sensitive to the compounds tested and β-citronellol showed a higher efficacy than DEET. In addition, β-citronellol could be formulated to protect humans and other animals from R. sanguineus s. l. and A. sculptum infestation, as well as the diseases transmitted by these species. Copyright © 2017 Elsevier B.V. All rights reserved.

Method To immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol

PubMed

Shah; Aebi; Tuor

1998-11-01

Erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. There have been few reported attempts to formulate this natural agent for use in biocontrol. In the current study, factors involved in the immobilization of E. neoaphidis hyphae in an alginate matrix were investigated. Hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. The optimal concentration of low-viscosity sodium alginate for production of conidia from entrapped hyphae was 1.5% (wt/vol), and 0.1 and 0.25 M calcium chloride were equally suitable for use as the gelling solution. Alginate beads were rinsed with 10% sucrose after gelling. However, beads should not be left for longer than 40 min in 0.1 M calcium chloride or 10% sucrose to prevent a 10% loss in conidial production. A 40% (vol/vol) concentration of fungal biomass produced significantly more conidia than either 20% or the standard concentration of 10%. This effect persisted even after beads were dried overnight in a laminar flow hood and stored at 4 degreesC for 4 days. Conidia from freshly produced alginate beads caused 27 to 32% infection in Pea aphids as determined by standardized laboratory bioassays. This finding was not significantly different from infections in aphids inoculated with fresh mycelial mats or plugs from Petri dish cultures. In conclusion, algination appears to be a promising technique for utilizing E. neoaphidis in the biocontrol of aphid pests.

Fabrication of High-Performance Polymer Bulk-Heterojunction Solar Cells by Interfacial Modifications I

DTIC Science & Technology

2009-04-30

P3HT:PCBM based polymer BHJ solar cells with configurations of ITO glass /PEDOT:PSS/P3HT:PCBM/PEGDE(0~6nm)/Al(100nm) and ITO glass /PEDOT:PSS/P3HT:PCBM...4% for inverted PV cells was reported using cesium carbonate (Cs2CO3) as ECL and vanadium oxide ( V2O5 ) as the hole collecting layer (HCL)9. However... glass Petri dish. The active film thickness was about 200 nm ±10 nm. SPDPA was dissolved in ethanol with 1 wt%. 10 nm of SPDPA was spin-coated onto the

Dynamic 3D culture promotes spontaneous embryonic stem cell differentiation in vitro.

PubMed

Gerlach, Jörg C; Hout, Mariah; Edsbagge, Josefina; Björquist, Petter; Lübberstedt, Marc; Miki, Toshio; Stachelscheid, Harald; Schmelzer, Eva; Schatten, Gerald; Zeilinger, Katrin

2010-02-01

Spontaneous in vitro differentiation of mouse embryonic stem cells (mESC) is promoted by a dynamic, three-dimensional (3D), tissue-density perfusion technique with continuous medium perfusion and exchange in a novel four-compartment, interwoven capillary bioreactor. We compared ectodermal, endodermal, and mesodermal immunoreactive tissue structures formed by mESC at culture day 10 with mouse fetal tissue development at gestational day E9.5. The results show that the bioreactor cultures more closely resemble mouse fetal tissue development at gestational day E9.5 than control mESC cultured in Petri dishes.

Phytotoxic clerodane diterpenes from Salvia miniata Fernald (Lamiaceae).

PubMed

Bisio, Angela; Damonte, Gianluca; Fraternale, Daniele; Giacomelli, Emanuela; Salis, Annalisa; Romussi, Giovanni; Cafaggi, Sergio; Ricci, Donata; De Tommasi, Nunziatina

2011-02-01

Our ongoing research to identify natural growth inhibitors with diterpene and triterpene skeletons exuding from the surface of the aerial parts of Salvia species led us to study Salvia miniata Fernald. Ten clerodane diterpenoids were found, along with three known diterpenes. Most of the isolated compounds from S. miniata inhibited the germination of Papaver rhoeas L. and Avena sativa L. in Petri dish experiments. Parallel results have been obtained in experiments carried out to evaluate the subsequent growth of the seedlings of the target species in the presence of the tested compounds. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effects of biaxial oscillatory shear stress on endothelial cell proliferation and morphology.

PubMed

Chakraborty, Amlan; Chakraborty, Sutirtha; Jala, Venkatakrishna R; Haribabu, Bodduluri; Sharp, M Keith; Berson, R Eric

2012-03-01

Wall shear stress (WSS) on anchored cells affects their responses, including cell proliferation and morphology. In this study, the effects of the directionality of pulsatile WSS on endothelial cell proliferation and morphology were investigated for cells grown in a Petri dish orbiting on a shaker platform. Time and location dependent WSS was determined by computational fluid dynamics (CFD). At low orbital speed (50 rpm), WSS was shown to be uniform (0-1 dyne/cm(2)) across the bottom of the dish, while at higher orbital speed (100 and 150 rpm), WSS remained fairly uniform near the center and fluctuated significantly (0-9 dyne/cm(2)) near the side walls of the dish. Since WSS on the bottom of the dish is two-dimensional, a new directional oscillatory shear index (DOSI) was developed to quantify the directionality of oscillating shear. DOSI approached zero for biaxial oscillatory shear of equal magnitudes near the center and approached one for uniaxial pulsatile shear near the wall, where large tangential WSS dominated a much smaller radial component. Near the center (low DOSI), more, smaller and less elongated cells grew, whereas larger cells with greater elongation were observed in the more uniaxial oscillatory shear (high DOSI) near the periphery of the dish. Further, cells aligned with the direction of the largest component of shear but were randomly oriented in low magnitude biaxial shear. Statistical analyses of the individual and interacting effects of multiple factors (DOSI, shear magnitudes and orbital speeds) showed that DOSI significantly affected all the responses, indicating that directionality is an important determinant of cellular responses. Copyright © 2011 Wiley Periodicals, Inc.

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland.

PubMed

Brown, Alissa J; Deutschman, Douglas H; Braswell, Jessica; McLaughlin, Dana

2016-01-01

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results.

Microscopic optical path length difference and polarization measurement system for cell analysis

NASA Astrophysics Data System (ADS)

Satake, H.; Ikeda, K.; Kowa, H.; Hoshiba, T.; Watanabe, E.

2018-03-01

In recent years, noninvasive, nonstaining, and nondestructive quantitative cell measurement techniques have become increasingly important in the medical field. These cell measurement techniques enable the quantitative analysis of living cells, and are therefore applied to various cell identification processes, such as those determining the passage number limit during cell culturing in regenerative medicine. To enable cell measurement, we developed a quantitative microscopic phase imaging system based on a Mach-Zehnder interferometer that measures the optical path length difference distribution without phase unwrapping using optical phase locking. The applicability of our phase imaging system was demonstrated by successful identification of breast cancer cells amongst normal cells. However, the cell identification method using this phase imaging system exhibited a false identification rate of approximately 7%. In this study, we implemented a polarimetric imaging system by introducing a polarimetric module to one arm of the Mach-Zehnder interferometer of our conventional phase imaging system. This module was comprised of a quarter wave plate and a rotational polarizer on the illumination side of the sample, and a linear polarizer on the optical detector side. In addition, we developed correction methods for the measurement errors of the optical path length and birefringence phase differences that arose through the influence of elements other than cells, such as the Petri dish. As the Petri dish holding the fluid specimens was transparent, it did not affect the amplitude information; however, the optical path length and birefringence phase differences were affected. Therefore, we proposed correction of the optical path length and birefringence phase for the influence of elements other than cells, as a prerequisite for obtaining highly precise phase and polarimetric images.

Dynamic monitoring of horizontal gene transfer in soil

NASA Astrophysics Data System (ADS)

Cheng, H. Y.; Masiello, C. A.; Silberg, J. J.; Bennett, G. N.

2015-12-01

Soil microbial gene expression underlies microbial behaviors (phenotypes) central to many aspects of C, N, and H2O cycling. However, continuous monitoring of microbial gene expression in soils is challenging because genetically-encoded reporter proteins widely used in the lab are difficult to deploy in soil matrices: for example, green fluorescent protein cannot be easily visualized in soils, even in the lab. To address this problem we have developed a reporter protein that releases small volatile gases. Here, we applied this gas reporter in a proof-of-concept soil experiment, monitoring horizontal gene transfer, a microbial activity that alters microbial genotypes and phenotypes. Horizontal gene transfer is central to bacterial evolution and adaptation and is relevant to problems such as the spread of antibiotic resistance, increasing metal tolerance in superfund sites, and bioremediation capability of bacterial consortia. This process is likely to be impacted by a number of matrix properties not well-represented in the petri dish, such as microscale variations in water, nutrients, and O2, making petri-dish experiments a poor proxy for environmental processes. We built a conjugation system using synthetic biology to demonstrate the use of gas-reporting biosensors in safe, lab-based biogeochemistry experiments, and here we report the use of these sensors to monitor horizontal gene transfer in soils. Our system is based on the F-plasmid conjugation in Escherichia coli. We have found that the gas signal reports on the number of cells that acquire F-plasmids (transconjugants) in a loamy Alfisol collected from Kellogg Biological Station. We will report how a gas signal generated by transconjugants varies with the number of F-plasmid donor and acceptor cells seeded in a soil, soil moisture, and soil O2 levels.

In vitro penetration of swine oocytes by homologous spermatozoa: Distinct systems for gamete's co-incubation and oocyte's cryopreservation.

PubMed

Macedo, M C; Lucia, T; Rambo, G; Ferreira Filho, E B; Rosa, A P; Fabiane, C; Cabral, M; Deschamps, J C

2010-02-01

In vitro penetration (IVP) of swine oocytes by homologous spermatozoa was evaluated in two experiments using four boars as semen donors. In experiment 1, the IVP rate and the number of penetrating spermatozoa (PSP) were compared using three co-incubation systems for vitrified oocytes and fresh sperm: (1) 35mL petri dishes in a CO(2) incubator, (2) 35mL petri dishes in bags (submarine system) and (3) glass flasks partially submerged in water bath with the same gas mixture used for the bag system. Mean PSP was 8.2+/-10.1 and the IVP rate was 90.5%. The PSP differed across all systems (P=0.0006): 15.5+/-0.5 for flasks, 6.3+/-0.4 for CO(2), and 3.9+/-0.4 for bags. The IVP rate for flasks (95.0%) was greater (P=0.01) than for CO(2) and bags (90.8% and 85.0%, respectively), but it did not differ between flasks and CO(2) for three boars (P>0.05). In experiment 2, co-incubation was done as described for glass flasks in experiment 1. The IVP rate and PSP were compared for cryopreserved oocytes: either vitrified in open pulled straws (OPS), or frozen in cryotubes. Mean PSP was 5.4+/-6.5 and IVP rate was 89.6%. Both PSP and IVP rate were greater (P<0.0001) for oocytes frozen in cryotubes (7.0+/-0.3% and 95.8%, respectively) than those frozen in OPS (3.7+/-0.3% and 83.4%, respectively), with no differences found for three boars (P>0.05). In summary, successful IVP of swine oocytes by homologous spermatozoa can be achieved using gametes incubated in glass flasks and oocytes frozen in cryotubes.

Catalytic Propulsion and Magnetic Steering of Soft, Patchy Microcapsules: Ability to Pick-Up and Drop-Off Microscale Cargo.

PubMed

Lu, Annie Xi; Liu, Yijing; Oh, Hyuntaek; Gargava, Ankit; Kendall, Eric; Nie, Zhihong; DeVoe, Don L; Raghavan, Srinivasa R

2016-06-22

We describe the creation of polymeric microcapsules that can exhibit autonomous motion along defined trajectories. The capsules are made by cross-linking aqueous microdroplets of the biopolymer chitosan using glutaraldehyde. A coflow microfluidic tubing device is used to generate chitosan droplets containing nanoparticles (NPs) with an iron (Fe) core and a platinum (Pt) shell. The droplets are then incubated in a Petri dish with the cross-linking solution, and an external magnet is placed below the Petri dish to pull the NPs together as a collective "patch" on one end of each droplet. This results in cross-linked capsules (∼150 μm in diameter) with an anisotropic (patchy) structure. When these capsules are placed in a solution of H2O2, the Pt shell of the NPs catalyzes the decomposition of H2O2 into O2 gas, which is ejected from the patchy end in the form of bubbles. As a result, the capsules (which are termed micromotors) move in a direction opposite to the bubbles. Furthermore, the micromotors can be steered along specific paths by an external magnet (the magnetic response arises due to the Fe in the core of the NPs). A given micromotor can thus be directed to meet with and adhere to an inert capsule, i.e., a model cargo. Adhesion occurs due to the soft nature of the two structures. Once the cargo is picked up, the micromotor-cargo pair can be moved along a specific path to a destination, whereupon the cargo can be released from the micromotor. We believe these soft micromotors offer significant benefits over their existing hard counterparts because of their biocompatibility, biodegradability, and ability to encapsulate a variety of payloads.

Influence of temperature on rate of uptake and subsequent horizontal transfer of [14C]fipronil by eastern subterranean termites (Isoptera: Rhinotermitidae).

PubMed

Spomer, Neil A; Kamble, Shripat T; Warriner, Richard A; Davis, Robert W

2008-06-01

The effect of temperature on [14C]fipronil uptake and transfer from donor (D) to recipient (R) Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) workers was evaluated. Test chambers used in the fipronil uptake study were constructed from petri dishes containing autoclaved soil treated with 1 ppm [14C]fipronil (1.14 microCi of total radioactivity per petri dish), distilled water, and R. flavipes workers. Test chambers were held in environmental growth chambers preset at 12, 17, 22, 27, and 32 degrees C. For the fipronil transfer study, donor termites stained with Nile blue-A were exposed to soil treated with 1 ppm [14C]fipronil for 2 h. Donors were then combined with unexposed recipient termite workers at either 1D:5R, 1D:10R, or 1D:20R ratios. Test chambers consisted of a nest and feeding chamber connected by a piece of polyethylene tube and held in growth chambers at 12, 17, 22, 27, and 32 degrees C. Worker termites were sampled over time and the amount of [14C]fipronil present was measured by scintillation counting. Some degree of uptake and transfer occurred at all temperatures and ratios in this study. The highest level of uptake occurred by termites held at 22-32 degrees C, followed decreasingly by 17 and 12 degrees C. Maximum transfer of [14C]fipronil occurred at the higher ratios (1:5 > 1:10 > 1:20) of donors to recipients. Data presented in this study suggest that temperature is one of the key factors affecting the rate of uptake and subsequent horizontal transfer of [14C]fipronil in subterranean termites.

A thin-layer liquid culture technique for the growth of Helicobacter pylori.

PubMed

Joo, Jung-Soo; Park, Kyung-Chul; Song, Jae-Young; Kim, Dong-Hyun; Lee, Kyung-Ja; Kwon, Young-Cheol; Kim, Jung-Min; Kim, Kyung-Mi; Youn, Hee-Shang; Kang, Hyung-Lyun; Baik, Seung-Chul; Lee, Woo-Kon; Cho, Myung-Je; Rhee, Kwang-Ho

2010-08-01

Several attempts have been successful in liquid cultivation of Helicobaccter pylori. However, there is a need to improve the growth of H. pylori in liquid media in order to get affluent growth and a simple approach for examining bacterial properties. We introduce here a thin-layer liquid culture technique for the growth of H. pylori. A thin-layer liquid culture system was established by adding liquid media to a 90-mm diameter Petri dish. Optimal conditions for bacterial growth were investigated and then viability, growth curve, and released proteins were examined. Maximal growth of H. pylori was obtained by adding 3 mL of brucella broth supplemented with 10% horse to a Petri dish. H. pylori grew in both DMEM and RPMI-1640 supplemented with 10% fetal bovine serum and 0.5% yeast extract. Serum-free RPMI-1640 supported the growth of H. pylori when supplemented with dimethyl-beta-cyclodextrin (200 microg/mL) and 1% yeast extract. Under optimal growth, H. pylori grew exponentially for 28 hours, reaching a density of 3.4 OD(600) with a generation time of 3.3 hours. After 24 hours, cultures at a cell density of 1.0 OD(600) contained 1.3 +/- 0.1 x 10(9 )CFU/mL. gamma-Glutamyl transpeptidase, nuclease, superoxide dismutase, and urease were not detected in culture supernatants at 24 hours in thin-layer liquid culture, but were present at 48 hours, whereas alcohol dehydrogenase, alkylhydroperoxide reductase, catalase, and vacuolating cytotoxin were detected at 24 hours. Thin-layer liquid culture technique is feasible, and can serve as a versatile liquid culture technique for investigating bacterial properties of H. pylori.

Automated single cell sorting and deposition in submicroliter drops

NASA Astrophysics Data System (ADS)

Salánki, Rita; Gerecsei, Tamás; Orgovan, Norbert; Sándor, Noémi; Péter, Beatrix; Bajtay, Zsuzsa; Erdei, Anna; Horvath, Robert; Szabó, Bálint

2014-08-01

Automated manipulation and sorting of single cells are challenging, when intact cells are needed for further investigations, e.g., RNA or DNA sequencing. We applied a computer controlled micropipette on a microscope admitting 80 PCR (Polymerase Chain Reaction) tubes to be filled with single cells in a cycle. Due to the Laplace pressure, fluid starts to flow out from the micropipette only above a critical pressure preventing the precise control of drop volume in the submicroliter range. We found an anomalous pressure additive to the Laplace pressure that we attribute to the evaporation of the drop. We have overcome the problem of the critical dropping pressure with sequentially operated fast fluidic valves timed with a millisecond precision. Minimum drop volume was 0.4-0.7 μl with a sorting speed of 15-20 s per cell. After picking NE-4C neuroectodermal mouse stem cells and human primary monocytes from a standard plastic Petri dish we could gently deposit single cells inside tiny drops. 94 ± 3% and 54 ± 7% of the deposited drops contained single cells for NE-4C and monocytes, respectively. 7.5 ± 4% of the drops contained multiple cells in case of monocytes. Remaining drops were empty. Number of cells deposited in a drop could be documented by imaging the Petri dish before and after sorting. We tuned the adhesion force of cells to make the manipulation successful without the application of microstructures for trapping cells on the surface. We propose that our straightforward and flexible setup opens an avenue for single cell isolation, critically needed for the rapidly growing field of single cell biology.

Influence of Light Intensity on Growth and Pigment Production by Monascus ruber in Submerged Fermentation.

PubMed

Bühler, Rose Marie Meinicke; Müller, Bruna Luíse; Moritz, Denise Esteves; Vendruscolo, Francielo; de Oliveira, Debora; Ninow, Jorge Luiz

2015-07-01

To reduce environmental problems caused by glycerine accumulation and to make the production of biodiesel more profitable, crude glycerin without treatment was used as substrate for obtaining higher value-added bioproducts. Monascus ruber is a filamentous fungus that produces pigments, particularly red ones, which are used for coloring foods (rice wine and meat products). The interest in developing pigments from natural sources is increasing due to the restriction of using synthetic dyes. The effects of temperature, pH, microorganism morphology, aeration, nitrogen source, and substrates have been studied in the cultivation of M. ruber. In this work, it was observed that light intensity is also an important factor that should be considered for understanding the metabolism of the fungus. In M. ruber cultivation, inhibition of growth and pigment production was observed in Petri dishes and blaffed flasks exposed to direct illumination. Growth and pigment production were higher in Petri dishes and flasks exposed to red light and in the absence of light. Radial growth rate of M. ruber in plates in darkness was 1.50 mm day(-1) and in plates exposed to direct illumination was 0.59 mm day(-1). Maximum production of red pigments (8.32 UA) and biomass (8.82 g L(-1)) were obtained in baffled flasks covered with red film and 7.17 UA of red pigments, and 7.40 g L(-1) of biomass was obtained in flasks incubated in darkness. Under conditions of 1248 lux of luminance, the maximum pigment production was 4.48 UA, with production of 6.94 g L(-1) of biomass, indicating that the fungus has photoreceptors which influence the physiological responses.

Physicochemical studies of equine infectious anemia virus: V. Effect of ultraviolet irradiation on virus infectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakajima, H.; Mizuno, Y.; Yasuda, K.

1973-03-01

The effect of ultraviolet radiation on the infectivity of equine infectious anemia (EIA) virus is described using influenza virus and Rous sarcoma (RSV) virus as controls. Virus preparations were placed in Petri dishes and uv- irradiated by a 15 watt germicidal lamp. At intervals up to 30 min samples were taken to determine the infectivity in surviving fractions. The infectivity of the influenza virus was reduced by four orders about 2 min after irradiation; the EIA virus infectivity was reduced to the same extent in 20 min, and the RSV infectivity was reduced to the same extent in 30 min.

Morphological Diversity of the Colony Produced by Bacteria Proteus mirabilis

NASA Astrophysics Data System (ADS)

Nakahara, Akio; Shimada, Yuji; Wakita, Jun-ichi; Matsushita, Mitsugu; Matsuyama, Tohey

1996-08-01

Morphological changes of colonies have been investigatedfor a bacterial strain of Proteus mirabilis, which is a famous speciesfor producing concentric-ring-like colonies. It was found that colony patterns can be classified into three types,i.e., cyclic spreading, diffusion-limited growth (DLA-like)and three-dimensional growth (inside the agar medium) patterns. Cyclic spreading patterns can further be classifiedinto three subgroups, i.e., concentric-ring, homogeneous and spatiotemporal patterns. These subgroups were classified by examining the development of colony structure after colonies spread all over petri-dishes. Comparison of the results with thoseof another bacterial species Bacillus subtilis is also discussed.

Toxicity of seven foliar insecticides to four insect parasitoids attacking citrus and cotton pests.

PubMed

Prabhaker, Nilima; Morse, J G; Castle, S J; Naranjo, S E; Henneberry, T J; Toscano, N C

2007-08-01

Laboratory studies were carried out to compare the toxicity of seven foliar insecticides to four species of adult beneficial insects representing two families of Hymenoptera: Aphelinidae (Aphytis melinus Debach, Eretmocerus eremicus Rose & Zolnerowich, and Encarsiaformosa Gahan) and Mymaridae (Gonatocerus ashmeadi Girault) that attack California red scale, Aonidiella aurantii (Maskell); sweetpotato whitefly, Bemisia tabaci (Gennadius) (both E. eremicus and E. formosa); and glassy-winged sharpshooter, Homalodisca vitripennis (Germar), respectively. Insecticides from four pesticide classes were evaluated using a petri dish bioassay technique across a range of concentrations to develop dosage-mortality regressions. Insecticides tested included acetamiprid (neonicotinoid); chlorpyrifos (organophosphate); bifenthrin, cyfluthrin, and fenpropathrin (pyrethroids); and buprofezin and pyriproxyfen (insect growth regulators [IGRs]). Chlorpyrifos was consistently the most toxic pesticide to all four species of beneficial insects tested based on LC50 values recorded 24 h posttreatment compared with 48-h LC50 values with the neonicotinoid and pyrethroids or 96 h with the IGRs. Among the three pyrethroids, fenpropathrin was usually less toxic (except similar toxicity to A. melinus) than was cyfluthrin, and it was normally less toxic (except similar toxicity with E. formosa) than was bifenthrin. Acetamiprid was generally less toxic than bifenthrin (except similar toxicity with G. ashmeadi). The IGRs buprofezin and pyriproxyfen were usually less toxic than the contact pesticides, but we did not test for possible impacts on female fecundity. For all seven pesticides tested, A. melinus was the most susceptible parasitoid of the four test species. The data presented here will provide pest managers with specific information on the compatibility of select insecticides with natural enemies attacking citrus and cotton, Gossypium hirsutum L., pests.

Characterization of a phosphate solubilizing and antagonistic strain of Pseudomonas putida (B0) isolated from a sub-alpine location in the Indian Central Himalaya.

PubMed

Pandey, Anita; Trivedi, Pankaj; Kumar, Bhavesh; Palni, Lok Man S

2006-08-01

The morphological, biochemical, and physiological characteristics of a phosphate solubilizing and antagonistic bacterial strain, designated as B0, isolated from a sub-alpine Himalayan forest site have been described. The isolate is gram negative, rod shaped, 0.8 x 1.6 microm in size, and psychrotrophic in nature that could grow from 0 to 35 degrees C (optimum temp. 25 degrees C). It exhibited tolerance to a wide pH range (3-12; optimum 8.0) and salt concentration up to 4% (w/v). Although it was sensitive to kanamycin, gentamicin, and streptomycin (<10 microg mL(-1)), it showed resistance to higher concentrations of ampicillin, penicillin, and carbenicillin (>1000 microg mL(-1)). The isolate showed maximum similarity with Pseudomonas putida based on 16S rRNA analysis. It solubilized tricalcium phosphate under in vitro conditions. The phosphate solubilization was estimated along a temperature range (4-28 degrees C), and maximum activity (247 microg mL(-1)) was recorded at 21 degrees C after 15 days of incubation. The phosphate solubilizing activity coincided with a concomitant decrease in pH of the medium. The isolate also exhibited antifungal activity against phytopathogenic fungi in Petri dish assays and produced chitinase, ss-l,3-glucanase, salicylic acid, siderophore, and hydrogen cyanide. The plant growth promotion and antifungal properties were demonstrated through a maize-based bioassay under greenhouse conditions. Although the bacterial inoculation was found to result in significant increment in plant biomass, it stimulated bacterial and suppressed fungal counts in the rhizosphere. The present study is important with respect to enumerating microbial diversity of the colder regions as well as understanding the potential biotechnological applications of native microbes.

A high-throughput seed germination assay for root parasitic plants

PubMed Central

2013-01-01

Background Some root-parasitic plants belonging to the Orobanche, Phelipanche or Striga genus represent one of the most destructive and intractable weed problems to agricultural production in both developed and developing countries. Compared with most of the other weeds, parasitic weeds are difficult to control by conventional methods because of their life style. The main difficulties that currently limit the development of successful control methods are the ability of the parasite to produce a tremendous number of tiny seeds that may remain viable in the soil for more than 15 years. Seed germination requires induction by stimulants present in root exudates of host plants. Researches performed on these minute seeds are until now tedious and time-consuming because germination rate is usually evaluated in Petri-dish by counting germinated seeds under a binocular microscope. Results We developed an easy and fast method for germination rate determination based on a standardized 96-well plate test coupled with spectrophotometric reading of tetrazolium salt (MTT) reduction. We adapted the Mosmann’s protocol for cell cultures to germinating seeds and determined the conditions of seed stimulation and germination, MTT staining and formazan salt solubilization required to obtain a linear relationship between absorbance and germination rate. Dose–response analyses were presented as applications of interest for assessing half maximal effective or inhibitory concentrations of germination stimulants (strigolactones) or inhibitors (ABA), respectively, using four parameter logistic curves. Conclusion The developed MTT system is simple and accurate. It yields reproducible results for germination bioassays of parasitic plant seeds. This method is adapted to high-throughput screenings of allelochemicals (stimulants, inhibitors) or biological extracts on parasitic plant seed germination, and strengthens the investigations of distinctive features of parasitic plant germination. PMID:23915294

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland

PubMed Central

Deutschman, Douglas H.; Braswell, Jessica; McLaughlin, Dana

2016-01-01

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results. PMID:27764200

Transformation of triploid bermudagrass (Cynodon dactylon x C. transvaalensis cv. TifEagle) by means of biolistic bombardment.

PubMed

Zhang, G; Lu, S; Chen, T A; Funk, C R; Meyer, W A

2003-06-01

A transformation system for triploid bermudagrass ( Cynodon dactylon x C. transvaalensis cv. TifEagle) was established with a biolistic bombardment delivery system. Embryogenic callus was induced from stolons and maintained on Murashige and Skoog's medium supplemented with 30 microM dicamba, 20 microM benzylaminopurine, and 100 mg/l myo-inositol. Using the hygromycin phosphotransferase ( hpt) gene as the selectable marker gene, we obtained 75 transgenic lines from 18 petri dishes bombarded. Integration of the hpt gene into genomic DNA and transcription of hpt was confirmed by Southern and Northern blot analyses, respectively. Through suspension culture screening, we obtained homogeneously transformed plants showing stable transcription of the hpt gene.

High Fidelity Additive Manufacturing of Optically Transparent Glass Structures

NASA Astrophysics Data System (ADS)

Inamura, Chikara

Glass has been an integral part of human civilization with expressions across scales and disciplines: from the microscope to the telescope, from fiber optics to mobile interface, and from the petri dish to a building envelope. Such a diverse range of applications is enabled by the inherent material properties including mechanical strength, optical transparency and chemical inertness. Additive manufacturing provides opportunities for integrating the unique properties of glass to engineer novel structures that are functionary graded through precise spatiotemporal deposition of molten glass. This talk presents the Mediated Matter Group's latest development of a novel additive manufacturing platform, and related processes, for 3D Printing optically transparent glass for architectural scale applications.

Morphology of eggs of Dioctophyme renale Goeze, 1782 (Nematoda: Dioctophymatidae) and influences of temperature on development of first-stage larvae in the eggs.

PubMed

Pedrassani, Daniela; Lux Hoppe, Estevam Guilherme; Avancini, Neuri; do Nascimento, Adjair Antonio

2009-01-01

This study aims to provide information on morphological data of D. renale eggs, as well as on first-stage larvae development into eggs kept at different temperatures. Eggs were obtained by centrifugation of infected dog urine, placed in Petri dishes, and stored in BOD chamber for a 90-day period. Each treatment (GI--15 degrees C, GII--20 degrees C, and GIII--26 degrees C) was repeated five times. Eggs showed average measures of 67.23 x 42.78 microm, and the mean incubation time was inversely proportional to the incubation temperature. Larvae motility was observed one week after being observed in eggs.

Efficiency trial of 80% thiophanate-methyl and 72% streptomycin against konjac bacterial soft rot

NASA Astrophysics Data System (ADS)

Lin, Tianxing; Gong, Mingfu; Guan, Qinlan; Tan, Chunyan

2018-04-01

Amorphophallus konjac soft rot can cause severe yield losses, and the effects agent to prevent the disease had not been found currently in production. In this dissertation, inhibition on konjac soft rot bacteria of seven agricultural fungicides, as benzene ring yl ether, methyl thiophanate, streptomycin sulfate, methane frost hymexazol, bismerthiazol WP, gray mold and Dyson Mn-Zn, was determined by antagonistic petri dish method. The results indicated that: the tested fungicide s had certain inhibition on konjac soft rot bacteria, and the inhibitory effect of different fungicides was significant difference. 80% thiophanate-methyl and 72% streptomycin sulfate had a good inhibitory effect on konjac soft rot disease bacteria.

The combined mode of action of fipronil and amitraz on the motility of Rhipicephalus sanguineus.

PubMed

Prullage, Joseph B; Tran, Hai V; Timmons, Phil; Harriman, Jay; Chester, S Theodore; Powell, Kerrie

2011-07-15

The motility of adult Rhipicephalus sanguineus was evaluated subsequent to treatments of amitraz, fipronil and the combination of fipronil plus amitraz against a vehicle control in a Petri dish assay using the LemnaTec Scanalyzer Imaging System. The assay was run using a fixed dilution of amitraz (0.32μg/cm(2)); serial dilutions of fipronil (1.3, 0.33, 0.08, 0.02, or 0.005μg/cm(2)); and the same serial dilutions of fipronil in combination with the fixed dilution of amitraz. Measurement of motility was made of unstimulated ticks and then after stimulation at 1, 4, 18-22, and 24h post exposure (hpe) of the Petri dishes. For the unstimulated ticks, there was no difference in motility between the amitraz treatment group and the fipronil plus amitraz treatment group at the early time points. However, these two treatment groups had significantly higher motility than the solvent control and fipronil treatment groups. The unstimulated ticks in the amitraz treatment group had significantly higher motility than the fipronil plus amitraz treatment group at the later time points. Measurements after stimulation demonstrated there was no difference in motility between the amitraz treatment group and the fipronil plus amitraz treatment group at the early time points. By 18 hpe, the fipronil plus amitraz treatment group had significantly lower motility than all other treatment groups and at 21-22 and 24 hpe the other treatment groups did not differ from the control group. The action could be divided in two phases in the combination experiment: phase 1: an early increase in motility due to amitraz is identified in both amitraz alone or fipronil plus amitraz groups; phase 2: the combination of fipronil plus amitraz caused a significantly greater reduction in motility, suggesting mortality of the ticks, compared to fipronil or amitraz alone. These results demonstrate a synergism resulting from the combination of fipronil plus amitraz. Copyright © 2011 Elsevier B.V. All rights reserved.

Predation of Ancylostoma spp. dog infective larvae by nematophagous fungi in different conidial concentrations.

PubMed

Maciel, A S; Araújo, J V; Campos, A K; Lopes, E A; Freitas, L G

2009-05-12

In the present work, it was evaluated the in vitro effect of 12 isolates from the fungal species Arthrobotrys, Duddingtonia, Nematoctonus and Monacrosporium genera in different conidial concentrations on the capture of Ancylostoma spp. dog infective larvae (L(3)), on 2% water-agar medium at 25 degrees C, at the end of a period of 7 days. The concentrations used for each nematophagous fungus were 1000, 5000, 10,000, 15,000 and 20,000conidia/Petri dish plated with 1000 Ancylostoma spp. L(3). All nematode-trapping fungi isolates tested reduced the averages of the uncaptured Ancylostoma spp. L(3) recovered, with the increase of the fungal inoculum concentration, in comparison to the fungus-free control (p<0.05). The adhesive network producing species were better predators than the constricting ring or adhesive knob producing species. Duddingtonia flagrans (Isolate CG768) was the most effective, reducing the averages of the uncaptured Ancylostoma spp. L(3) recovered in 92.8%, 96.3%, 97.5%, 98.3% and 98.9%, respectively in five fungal inoculum concentrations established. Other effective nematophagous fungi were Arthrobotrys robusta (Isolate I31), which reduced the averages of the uncaptured Ancylostoma spp. L(3) recovered in 85.4%, 88.3%, 90.7%, 92.5% and 95.2%, and Arthrobotrys oligospora (Isolate A183), with reductions of 66.6%, 79.8%, 86.8%, 89.5% and 90.8%, respectively for both, in the five fungal inoculum concentrations established. No difference was found between Isolates A183 and I31 in the conidial concentrations of 15,000/Petri dish. Nematoctonus robustus (Isolate D1) and Arthrobotrys bronchophaga (Isolate AB) had the smallest percentages of reduction among the tested isolates and showed the lowest predacious activity. The Isolates CG768, I31 and A183 were considered potential biological control agents of Ancylostoma spp. dog free-living stages, being directly influenced by the fungal inoculum concentration.

Effect of the fungus Pochonia chlamydosporia on Echinostoma paraensei (Trematoda: Echinostomatidae).

PubMed

Lelis, Rosane Teixeira; Braga, Fabio Ribeiro; de Carvalho, Lorendane Millena; de Paula, Alessandra Teixeira; Araujo, Juliana Milani; Fausto, Mariana Costa; Junior, Arnaldo Maldonado; Rodrigues, João Victor Facchini; de Freitas Soares, Filippe Elias; Garcia, Juberlan Silva; de Araújo, Jackson Victor

2014-11-01

Echinostoma paraensei is a trematode of the genus Echinostoma that causes echinostomiasis in humans. The objectives of this study were to: evaluate the ovicidal activity of the nematophagous fungus Pochonia chlamydosporia (VC1 and VC4) on a solid medium 2% water-agar (2% WA) against E. paraensei eggs (assay A); evaluate ovicidal effect (destruction of eggs) of the isolate VC4 in supplemented culture media (assay B); and evaluate the ovicidal ability of the crude extract (VC4) on E. paraensei eggs (assay C). Eggs of E. paraensei (assay A) were placed in Petri dishes containing 2% WA with an isolate of the fungus P. chlamydosporia (VC1 and VC4) grown for 10 days, and without fungus as a control and evaluated regarding their destruction. In assay B, eggs of E. paraensei were placed in Petri dishes with different supplemented culture media and with VC4 isolate and the destruction of eggs was examined at the end of 25 days of interaction. In assay C, effects of the crude extract of P. chlamydosporia (VC4) on eggs were evaluated at the end of 7 days. In assay A, there was no difference (p>0.05) in ovicidal activity among the tested isolates (VC1 and VC4); however, the highest percentage for ovicidal activity (type 3 effect) was demonstrated by the isolate VC4. In assay B, the culture medium starch-agar showed the best results for the destruction of the eggs, with a percentage of 46.6% at the end of the assay. In assay C, the crude extract of VC4 was effective in the destruction of E. paraensei eggs, with a percentage reduction of 53%. The results of this study demonstrate that a rich culture medium with a greater availability of carbon and nitrogen may interfere directly in the predatory characteristics of ovicidal fungi. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng

2015-05-01

Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near future.

Ferromagnetic movements of middle ear implants and stapes prostheses in a 3-T magnetic resonance field.

PubMed

Fritsch, Michael H; Gutt, Jason J

2005-03-01

A 3-T magnetic resonance field may cause motion or displacement of middle ear implants not seen in studies with 1.5-T magnets. Previous publications have described the safety limitations of some otologic implants in 1.5-T magnetic resonance fields. Several company-wide recalls of implants were issued. No studies to date have been reported for otologic implants within a 3-T magnetic resonance field, nor have there been comparisons with a 1.5-T field strength. Eighteen commonly used middle ear implants and prostheses were selected. In Part 1, the prostheses were placed in Petri dishes and exposed to a 3-T magnetic resonance field. In Part 2, the particular prostheses that showed movement in Part 1 were placed into their intended use positions within temporal bone laboratory specimens and exposed to a 3-T field. Both parts were repeated in a 1.5-T field. In Part 1, three prostheses moved dramatically from their start positions when exposed to the 3-T magnetic resonance field. In Part 2, the three particular prostheses that showed movement in Part 1 showed no gross displacement or movement from their start positions within the temporal bone laboratory specimens. No implants moved in the 1.5-T field in either Part 1 or Part 2. Certain stapes prostheses move dramatically in Petri dishes in 3-T fields. When placed into temporal bone laboratory specimens, the same prostheses show no signs of movement from the surgical site in a 3-T field, and it appears that the surgical position holds the implants firmly in place. Results of published 1.5-T field studies should not be used directly for safety recommendations in a 3-T magnetic resonance. Heat, voltage induction, and vibration during exposure to the magnetic resonance fields should be considered as additional possible safety issues. Preference should be given to platinum and titanium implants in manufacturing processes and surgical selection.

Tolerance of triazole-based fungicides by biocontrol agents used to control Fusarium head blight in wheat in Argentina.

PubMed

Palazzini, J M; Torres, A M; Chulze, S N

2018-05-01

Fusarium head blight (FHB) caused by Fusarium graminearum species complex is a devastating disease that causes extensive yield and quality losses to wheat around the world. Fungicide application and breeding for resistance are among the most important tools to counteract FHB. Biological control is an additional tool that can be used as part of an integrated management of FHB. Bacillus velezensisRC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B were selected by their potential to control FHB and deoxynivalenol production. The aim of this work was to test the tolerance of these biocontrol agents to triazole-based fungicides such as prothioconazole, tebuconazole and metconazole. Bacterial growth was evaluated in Petri dishes using the spread plating technique containing the different fungicides. Bacillus velezensisRC 218 and Streptomyces sp. RC 87B showed better tolerance to fungicides than Brevibacillus sp. RC 263. Complete growth inhibition was observed at concentrations of 20 μg ml -1 for metconazole, 40 μg ml -1 for tebuconazole and 80 μg ml -1 for prothioconazole. The results obtained indicate the possibility of using these biocontrol agents in combination with fungicides as part of an integrated management to control FHB of wheat. This study evaluates the possibility to use biocontrol agents (Bacillus velezensisRC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B) in combination with triazole-based fungicides to control Fusarium head blight in wheat. The evaluation of biocontrol agents' growth under in vitro conditions was carried out in Petri dishes containing either prothioconazole, tebuconazole or metconazole. Viability studies demonstrated that B. velezensisRC 218 and Streptomyces sp. RC 87B were more tolerant to the fungicides evaluated. Results obtained reflect the possibility to use fungicides at low doses combined with biocontrol agents. © 2018 The Society for Applied Microbiology.

A Comparative Chemical Study of Calcium Silicate-Containing and Epoxy Resin-Based Root Canal Sealers.

PubMed

Reszka, Przemysław; Nowicka, Alicja; Lipski, Mariusz; Dura, Włodzimierz; Droździk, Agnieszka; Woźniak, Krzysztof

2016-01-01

Objective. The present study assessed the chemical elements in two novel calcium silicate-containing root canal sealers, BioRoot RCS and Well-Root ST, compared to a calcium silicate-containing root canal sealer that has been on the market for several years, MTA Fillapex, and epoxy resin-based sealer AHPlus. Material and Methods. The sealers were mixed and manipulated according to the manufacturers' instructions. Twelve cylindrical molds (inner diameter 4 mm; height 3 mm) were placed on a glass petri dish and packed with the materials. The dish was transferred to an incubator. After 72 h the molds were examined by scanning electron microscopy and energy dispersive X-ray microanalysis. Results. BioRoot RCS and Well-Root ST had high peaks of calcium, zirconium, oxygen, carbon, silicon, and chlorine. Well-Root ST also had sodium, magnesium, aluminum, and titanium peaks. MTA Fillapex and AHPlus had carbon, oxygen, calcium, titanium, and bismuth peaks. A silicon peak was also observed for MTA Fillapex, and zirconium and tungsten peaks for AHPlus. Conclusion. BioRoot RSC had the highest degree of purity. The clinical implication of metals contained in the other sealers needs to be investigated.

A Comparative Chemical Study of Calcium Silicate-Containing and Epoxy Resin-Based Root Canal Sealers

PubMed Central

Reszka, Przemysław; Dura, Włodzimierz; Droździk, Agnieszka; Woźniak, Krzysztof

2016-01-01

Objective. The present study assessed the chemical elements in two novel calcium silicate-containing root canal sealers, BioRoot RCS and Well-Root ST, compared to a calcium silicate-containing root canal sealer that has been on the market for several years, MTA Fillapex, and epoxy resin-based sealer AHPlus. Material and Methods. The sealers were mixed and manipulated according to the manufacturers' instructions. Twelve cylindrical molds (inner diameter 4 mm; height 3 mm) were placed on a glass petri dish and packed with the materials. The dish was transferred to an incubator. After 72 h the molds were examined by scanning electron microscopy and energy dispersive X-ray microanalysis. Results. BioRoot RCS and Well-Root ST had high peaks of calcium, zirconium, oxygen, carbon, silicon, and chlorine. Well-Root ST also had sodium, magnesium, aluminum, and titanium peaks. MTA Fillapex and AHPlus had carbon, oxygen, calcium, titanium, and bismuth peaks. A silicon peak was also observed for MTA Fillapex, and zirconium and tungsten peaks for AHPlus. Conclusion. BioRoot RSC had the highest degree of purity. The clinical implication of metals contained in the other sealers needs to be investigated. PMID:28097154

The third dimension bridges the gap between cell culture and live tissue.

PubMed

Pampaloni, Francesco; Reynaud, Emmanuel G; Stelzer, Ernst H K

2007-10-01

Moving from cell monolayers to three-dimensional (3D) cultures is motivated by the need to work with cellular models that mimic the functions of living tissues. Essential cellular functions that are present in tissues are missed by 'petri dish'-based cell cultures. This limits their potential to predict the cellular responses of real organisms. However, establishing 3D cultures as a mainstream approach requires the development of standard protocols, new cell lines and quantitative analysis methods, which include well-suited three-dimensional imaging techniques. We believe that 3D cultures will have a strong impact on drug screening and will also decrease the use of laboratory animals, for example, in the context of toxicity assays.

Extinction transition in bacterial colonies under forced convection

NASA Astrophysics Data System (ADS)

Neicu, T.; Pradhan, A.; Larochelle, D. A.; Kudrolli, A.

2000-07-01

We report the spatiotemporal response of Bacillus subtilis growing on a nutrient-rich layer of agar to ultraviolet (UV) radiation. Below a crossover temperature, the bacteria are confined to regions that are shielded from UV radiation. A forced convection of the population is effected by rotating a UV radiation shield relative to the Petri dish. The extinction speed at which the bacterial colony lags behind the shield is found to be qualitatively similar to the front velocity of the colony growing in the absence of a hostile environment as predicted by the model of Dahmen, Nelson, and Shnerb. A quantitative comparison is not possible without considering the slow dynamics and time-dependent interaction of the population with the hostile environment.

Tracking zebrafish larvae in group – Status and perspectives☆

PubMed Central

Martineau, Pierre R.; Mourrain, Philippe

2013-01-01

Video processing is increasingly becoming a standard procedure in zebrafish behavior investigations as it enables higher research throughput and new or better measures. This trend, fostered by the ever increasing performance-to-price ratio of the required recording and processing equipment, should be expected to continue in the foreseeable future, with video-processing based methods permeating more and more experiments and, as a result, expanding the very role of behavioral studies in zebrafish research. To assess whether the routine video tracking of zebrafish larvae directly in the Petri dish is a capability that can be expected in the near future, the key processing concepts are discussed and illustrated on published zebrafish studies when available or other animals when not. PMID:23707495

Does incineration turn infectious waste aseptic?

PubMed

Kanemitsu, K; Inden, K; Kunishima, H; Ueno, K; Hatta, M; Gunji, Y; Watanabe, I; Kaku, M

2005-08-01

Incineration of infectious waste is considered to be biologically safe. We performed basic experiments to confirm that bacillus spores are killed by incineration in a muffle furnace. Biological samples containing 10(6) spores of Bacillus stearothermophilus were placed in stainless steel Petri dishes and then into hot furnaces. The furnace temperature and duration of incineration were 300 degrees C for 15 min, 300 degrees C for 30 min, 500 degrees C for 15 min, 500 degrees C for 30 min and 1100 degrees C for 3 min. We confirmed that all spores of B. stearothermophilus were killed at each of these settings. The effect of incineration seems to be equivalent to that of sterilization, based on the satisfactory sterilization assurance level of 10(-6).

Mycodiversity in marine sediments contaminated by heavy metals: preliminary results

NASA Astrophysics Data System (ADS)

Zotti, Mirca; Carbone, Cristina; Cecchi, Grazia; Consani, Sirio; Cutroneo, Laura; Di Piazza, Simone; Gabutto, Giacomo; Greco, Giuseppe; Vagge, Greta; Capello, Marco

2016-04-01

Fungi represent the main decomposers of woody and herbaceous substrates in the marine ecosystems. To date there is a gap in the knowledge about the global diversity and distribution of fungi in marine habitats. On the basis of their biological diversity and their role in ecosystem processes, marine fungi may be considered one of the most attractive groups of organisms in modern biotechnology, e.g. ecotoxic metal bioaccumulation. Here we report the data about the first mycological survey in the metal contaminated coastal sediments of the Gromolo Bay. The latter is located in Ligurian Sea (Eastern Liguria, Italy) and is characterized by an enrichment of heavy metals due to pollution of Gromolo Torrent by acidic processes that interest Fe-Cu sulphide mine. 24 samples of marine sediments were collected along a linear plot in front of the shoreline in July 2015. Each sample was separated into three aliquot for mineralogical, chemical analyses and fungal characterization. The sediment samples are characterised by clay fractions (illite and chlorite), minerals of ophiolitic rocks (mainly serpentine, pyroxene and plagioclase) and quartz and are enriched some chemical elements of environmental importance (such as Cu, Zn, Pb, Cd, As). For fungal characterisation the sediment samples were inoculated in Petri dishes on different culture media (Malt Extract Agar and Rose Bengal) prepared with sea water and added with antibiotics. The inoculated dishes were incubated at 20°C in the dark for 28 days. Every week fungal growth was monitored counting the number of colonies. Later, the colonies were isolated in axenic culture for further molecular analysis. The mycodiversity evaluate on the basis of Colony Forming Units (CFU) and microfungal-morphotype characterised by macro-and micro-morphology. Until now on the 72 Petri dishes inoculated 112 CFU of filamentous fungi were counted, among these about 50 morphotypes were characterized. The quantitative results show a mean value of 4.6 CFU per gram of sediments. The maximum value of 11 CFU g-1 has been recorded in two stations (off the Sestri Levante Tombolo), while the minimum value has been recorded closer to the coast. As concern qualitative results, the most recurrent genera are Aspergillus and Penicillium. These data confirm the occurrence of a mycobiota in these heavy metal contaminated sediments. Our preliminary results are a first contribution to the knowledge of presence of microfungi in marine sediments, and propel us to increase our research in order to find out new organisms for bioremediation purpose.

The fungistatic and fungicidal effects of volatiles from metathoracic glands of soybean-attacking stink bugs (Heteroptera: Pentatomidae) on the entomopathogen Beauveria bassiana.

PubMed

Lopes, Rogério B; Laumann, Raul A; Blassioli-Moraes, Maria C; Borges, Miguel; Faria, Marcos

2015-11-01

This study was initially designed to evaluate the differential susceptibility of three soybean-attacking pentatomids to the entomopathogenic fungus Beauveria bassiana in standardized bioassays. Euschistus heros (Eh) was shown to be significantly less susceptible than Chinavia ubica (Cu), whereas Dichelops melacanthus (Dm) adults were highly susceptible to fungal infections. A deeper look at the mechanisms involved in the possible role of volatiles from metathoracic glands on fungal infections was undertaken, and gland extracts from Nezara viridula (Nv), a species known for its resilience to fungal infections, were also included in the assays. Atmospheres with volatiles from pentatomids with very low-susceptibility to B. bassiana infections (Eh and Nv) had a significant effect on speed of germination as shown in counts performed up to 22h post-inoculation, by which time 0.1 (control), 0.6 (Dm), 17.9 (Cu), 32.6 (Eh), and 43.4% (Nv) of conidia had not germinated. The fungistatic (inhibitory) and fungicidal (lethal) effects of Eh and Nv volatile-rich atmospheres were subsequently quantified in Petri dishes with either PDA or PDA medium amended with carbendazim, which allowed germination rates to be determined at 18 and 48h post-inoculation, respectively. As opposed to control, Eh volatile-rich atmosphere had a clear fungistatic effect, since germination rate was only 27.4% within 18h, but reached 99.4% at 48h post-inoculation. For Nv volatile-rich atmospheres, only 15.1% of conidia germinated within 18h, and by 48h post-inoculation, approx. 18% of conidia were unviable (neither germ tubes nor intumescence), whereas in the control treatment rates were >99% at both reading times. Therefore, the gaseous phase of defensive secretions from fungus-resilient pentatomids possess a strong inhibitory effect and may display a less pronounced lethal effect on fungal germination, as was the case for Nv. Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical composition and efficacy of some selected plant oils against Pediculus humanus capitis in vitro.

PubMed

Yones, Doaa A; Bakir, Hanaa Y; Bayoumi, Soad A L

2016-08-01

Natural compounds have been suggested as alternative sources for pediculosis capitis control. We aimed to investigate the chemical composition and evaluate the pediculicidal activity of spearmint, clove, cassia, thyme, eucalyptus, and anise essential oils in addition to sesame oil against human head lice in vitro. A filter paper contact bioassay method was used by applying 0.25 and 0.5 mg/cm(2) of each tested oil to filter paper in Petri dishes with 15 females head lice and another with ten nits. The lice mortalities were reported every 5 min for 180 min. The percentage of inhibition of hatch (PIH) was used to calculate ovicidal activity by daily microscopic inspections 5 days after the hatching of controls. Comparison with the widely used pediculicide (malathion) was performed. The most effective essential oil was spearmint followed by cassia and clove with KT50 values of 4.06, 7.62, and 12.12 at 0.5 mg/cm(2) and 8.84, 11.38, and 19.73 at 0.25 mg/cm(2), respectively. Thyme, eucalyptus, and anise were also effective adulticides with KT50 values of 18.61, 32.65, and 37.34 at 0.5 mg/cm(2) and 29.92, 43.16, and 45.37 at 0.25 mg/cm(2), respectively. Essential oils were also successful in inhibiting nymph emergence. Spearmint oil was the most effective, with a complete inhibition of emergence at 0.5 mg/cm(2). Sesame fixed oil did not show any adulticidal or ovicidal activity against head lice in vitro. The observed insecticidal activity was comparable to malathion. The results herein described the effectiveness of these essential oils as potential pediculicides for head lice control. Incorporation of essential oils in pediculicide formulations needs proper formulation and clinical trials.

Physiological and Molecular Characterization of Cephaleuros virescens Occurring in Mango Trees.

PubMed

Vasconcelos, Camila Vilela; Pereira, Fabíola Teodoro; Duarte, Elizabeth Amélia Alves; de Oliveira, Thiago Alves Santos; Peixoto, Nei; Carvalho, Daniel Diego Costa

2018-06-01

The objective of this work was to accomplish the isolation, molecular identification and characterizing the physiology of the causal agent of the algal spot in mango trees. For this purpose, the pathogen growth was assessed in different culture media, with subsequent observation and measurements of the filamentous cells. The molecular identification was made using mycelium obtained from leaf lesions and pure algae colonies grown in culture medium. Descriptions based on DNA sequencing indicated that the algae is Cephaleuros virescens . The algae must be isolated primarily in liquid medium for further pricking into agar medium. The highest mycelial growth average in Petri dishes occurred when the algae were grown in Trebouxia and BBM. Trebouxia enabled larger cells in the filamentous cells when compared to other culture media.

Population aging through survival of the fit and stable

NASA Astrophysics Data System (ADS)

Brotto, Tommaso; Bunin, Guy; Kurchan, Jorge

2016-03-01

Motivated by the wide range of known self-replicating systems, some far from genetics, we study a system composed by individuals having an internal dynamics with many possible states that are partially stable, with varying mutation rates. Individuals reproduce and die with a rate that is a property of each state, not necessarily related to its stability, and the offspring is born on the parent’s state. The total population is limited by resources or space, as for example in a chemostat or a Petri dish. Our aim is to show that mutation rate and fitness become more correlated, even if they are completely uncorrelated for an isolated individual, underlining the fact that the interaction induced by limitation of resources is by itself efficient for generating collective effects.

Disinfection of S. mutans Bacteria Using a Plasma Needle at Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Hansen, S.; Goree, J.; Liu, Bin; Drake, D.

2007-11-01

The plasma needle device produces a millimeter-size low-power glow discharge at atmospheric-pressure. It is intended for dental or medical applications. Radio-frequency high voltage is applied to a single needle electrode located inside a concentric gas-flow nozzle. A low-speed helium plasma jet flows out of the nozzle and mixes with ambient air. The jet is impinges on a surface that is to be treated, which in our test was a suspension of S. mutans bacteria that was plated onto the surface of agar nutrient in a Petri dish. S. mutans is the most important microorganism for causing dental caries. Imaging the sample after plasma treatment and incubation reveal the conditions where bacteria are killed, and the size of the treated spot.

The Space Microbe Invasion: To Eat or Not to Eat

NASA Technical Reports Server (NTRS)

Munoz, Angela; Jones, Wanda

2013-01-01

Objective: To investigate how different cleaning agents sanitize an assortment of vegetables and fruits for nsumption on board the International Space Station (ISS). -Description: This laboratory investigation will have students testing different cleaning agents on a variety of vegetables and fruits that can be grown on board the ISS. Students will determine which cleaning agent most effectively lowers the number of bacteria on a variety of vegetables and fruits. This lab will also lend itself to investigations dealing with pH and its' role in lowering bacterial counts. In addition, students will figure out the correct balance between plant architecture and effectiveness of sanitizing these surfaces to achieve lower bacteria counts. This will be determined based on swabbed bacteria samples later grown on a Petri dish.

Influence of Culture Media on Microbial Fingerprints Using Raman Spectroscopy.

PubMed

Mlynáriková, Katarína; Samek, Ota; Bernatová, Silvie; Růžička, Filip; Ježek, Jan; Hároniková, Andrea; Šiler, Martin; Zemánek, Pavel; Holá, Veronika

2015-11-24

Raman spectroscopy has a broad range of applications across numerous scientific fields, including microbiology. Our work here monitors the influence of culture media on the Raman spectra of clinically important microorganisms (Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans). Choosing an adequate medium may enhance the reproducibility of the method as well as simplifying the data processing and the evaluation. We tested four different media per organism depending on the nutritional requirements and clinical usage directly on a Petri dish. Some of the media have a significant influence on the microbial fingerprint (Roosvelt-Park Institute Medium, CHROMagar) and should not be used for the acquisition of Raman spectra. It was found that the most suitable medium for microbiological experiments regarding these organisms was Mueller-Hinton agar.

Influence of Culture Media on Microbial Fingerprints Using Raman Spectroscopy

PubMed Central

Mlynáriková, Katarína; Samek, Ota; Bernatová, Silvie; Růžička, Filip; Ježek, Jan; Hároniková, Andrea; Šiler, Martin; Zemánek, Pavel; Holá, Veronika

2015-01-01

Raman spectroscopy has a broad range of applications across numerous scientific fields, including microbiology. Our work here monitors the influence of culture media on the Raman spectra of clinically important microorganisms (Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans). Choosing an adequate medium may enhance the reproducibility of the method as well as simplifying the data processing and the evaluation. We tested four different media per organism depending on the nutritional requirements and clinical usage directly on a Petri dish. Some of the media have a significant influence on the microbial fingerprint (Roosvelt-Park Institute Medium, CHROMagar) and should not be used for the acquisition of Raman spectra. It was found that the most suitable medium for microbiological experiments regarding these organisms was Mueller-Hinton agar. PMID:26610516

Characteristics and Efficacy of a Sterile Hyphomycete (ARF18), a New Biocontrol Agent for Heterodera glycines and Other Nematodes.

PubMed

Kim, D G; Riggs, R D

1991-07-01

A filamentous, nonsporulating fungus, designated Arkansas Fungus 18 (ARF18), was isolated from 9 of 95 populations of Heterodera glycines, the soybean cyst nematode, in Arkansas. In petri dishes, ARF18 parasitized 89% of H. glycines eggs in cysts. The fungus also infected eggs of Meloidogyne incognita and eggs in cysts of Cactodera betulae, H. graminophila, H. lespedezae, H. leuceilyma, H. schachtii, and H. trifolii. In pot tests, reproduction of SCN was 70% less in untreated field soil that was naturally infested by ARF18 than in autoclaved field soil. Although ARF18 grew well at 25 C on cornmeal agar over a wide pH range, it did not sporulate on 28 media and thus could not be identified to genus or species.

Effect of PGE2 and LTB4 on vicia villosa binding lymphocytes.

PubMed

Gualde, N; Cook, J M; Guibert, F

1988-06-01

Since there is a good deal of evidence that vicia villosa lectin (VVA) binds to contrasuppressor cells, mouse splenocytes and thymocytes were sorted by binding to VVA-coated Petri dishes. It was observed that vicia villosa adherent cells (VVA(+)) did not proliferate when mitogens were added to cultures, but they did enhance the thymidine uptake of PHA or ConA stimulated vicia villosa non-adherent (VVA(-)) splenocytes. PGE2 treatment of VVA(+) splenocytes or VVA(+) immature thymocytes did not very much affect the VVA(+) cell behavior. On the other hand, LTB4 increased the enhancing capability of VVA(+) splenocytes. Therefore, investigations dealing with the effects of LTB4 on lymphocyte subsets which may include VVA(+) cells should take into consideration the possible presence of contrasuppressor cells.

Cultivation of animal cells in a reticulated vitreous carbon foam.

PubMed

Kent, B L; Mutharasan, R

1992-02-01

A reticulated vitreous carbon foam (RVCF) was used as a surface to cultivate a model anchorage-dependent animal cell line, 3T6 (mouse embryo fibroblast). This fixed-surface bioreactor provided a low-shear, chemically-inert, and reusable environment for cell growth. An external medium recirculation loop allowed aeration, nutrient monitoring, and medium replacement without disturbing the cells. Optimal flow rates for the attachment and growth phases were determined. Growth rates comparable to static (T-flask and petri dish) cultures and agitated microcarrier cultures were achieved with appropriately high medium recirculation rates. Metabolic parameters were shown to be useful indicators of cell mass, although specific glucose consumption rates were considerably higher for cultures in the RVCF reactor. Oxygen supply was shown to be the most likely limiting factor for scaleup.

LD50 and repellent effects of essential oils from Argentinian wild plant species on Varroa destructor.

PubMed

Ruffinengo, Sergio; Eguaras, Martin; Floris, Ignazio; Faverin, Claudia; Bailac, Pedro; Ponzi, Marta

2005-06-01

The repellent and acaricidal effects of some essential oils from the most typical wild plant species of northern Patagonia, Argentina, on Varroa destructor Anderson & Trueman were evaluated using a complete exposure test. Honey bees, Apis mellifera L., and mites (five specimens of each per dish) were introduced in petri dishes having different oil concentrations (from 0.1 to 25 micro per cage). Survival of bees and mites was registered after 24, 48, and 72 h. An attraction/repellence test was performed using a wax tube impregnated with essential oil and another tube containing wax only. The lowest LD50 values for mites were registered for Acantholippia seriphioides (A. Gray) Mold. (1.27 microl per cage) and Schinus molle L. (2.65 microl per cage) after 24 h, and for Wedelia glauca (Ortega) O. Hoffm. ex Hicken (0.59 microl per cage) and A. seriphioides (1.09 microl per cage) after 72 h of treatment. The oil with the highest selectivity ratio (A. mellifera LD50/V. destructor LD50) was the one extracted from S. molle (>16). Oils of Lippia junelliana (Mold.) Troncoso, Minthostachys mollis (HBK) Grieseb., and Lippia turbinata Grieseb. mixed with wax had repellent properties. None of the oils tested had attractive effects on Varroa mites.

Impact of saccharides on the drying kinetics of agarose gels measured by in-situ interferometry

NASA Astrophysics Data System (ADS)

Mao, Bosi; Divoux, Thibaut; Snabre, Patrick

2017-01-01

Agarose gels are viscoelastic soft solids that display a porous microstructure filled with water at 90% w/w or more. Despite an extensive use in food industry and microbiology, little is known about the drying kinetics of such squishy solids, which suffers from a lack of time-resolved local measurements. Moreover, only scattered empirical observations are available on the role of the gel composition on the drying kinetics. Here we study by in-situ interferometry the drying of agarose gels of various compositions cast in Petri dishes. The gel thinning is associated with the displacement of interference fringes that are analyzed using an efficient spatiotemporal filtering method, which allows us to assess local thinning rates as low as 10 nm/s with high accuracy. The gel thinning rate measured at the center of the dish appears as a robust observable to quantify the role of additives on the gel drying kinetics and compare the drying speed of agarose gels loaded with various non-gelling saccharides of increasing molecular weights. Our work shows that saccharides systematically decrease the agarose gel thinning rate up to a factor two, and exemplifies interferometry as a powerful tool to quantify the impact of additives on the drying kinetics of polymer gels.

Growing Neural PC-12 Cell on Crosslinked Silica Aerogels Increases Neurite Extension in the Presence of an Electric Field.

PubMed

Lynch, Kyle J; Skalli, Omar; Sabri, Firouzeh

2018-04-20

Externally applied electrical stimulation (ES) has been shown to enhance the nerve regeneration process and to influence the directionality of neurite outgrowth. In addition, the physical and chemical properties of the substrate used for nerve-cell regeneration is critical in fostering regeneration. Previously, we have shown that polyurea-crosslinked silica aerogels (PCSA) exert a positive influence on the extension of neurites by PC-12 cells, a cell-line model widely used to study neurite extension and electrical excitability. In this work, we have examined how an externally applied electric field (EF) influences the extension of neurites in PC-12 cells grown on two substrates: collagen-coated dishes versus collagen-coated crosslinked silica aerogels. The externally applied direct current (DC) bias was applied in vitro using a custom-designed chamber containing polydimethysiloxane (PDMS) embedded copper electrodes to create an electric field across the substrate for the cultured PC-12 cells. Results suggest orientation preference towards the anode, and, on average, longer neurites in the presence of the applied DC bias than with 0 V DC bias. In addition, neurite length was increased in cells grown on silica-crosslinked aerogel when compared to cells grown on regular petri-dishes. These results further support the notion that PCSA is a promising material for nerve regeneration.

Key acceptability attributes of orodispersible films.

PubMed

Scarpa, Mariagiovanna; Paudel, Amrit; Kloprogge, Frank; Hsiao, Wen Kai; Bresciani, Massimo; Gaisford, Simon; Orlu, Mine

2018-04-01

The features rendering orodispersible films (ODFs) patient-centric formulations are widely discussed in the scientific literature. However there is a lack of research studies exploring ODF characteristics with a potential impact on end-user acceptability. The aim of this study was to identify the key ODF characteristics affecting end-user acceptability by developing in vitro test methods for the prediction of ODFs acceptability and correlate these formulation characteristics with the data obtained from a human panel study. Four drug-free single-polymer films were prepared by solvent casting. Solutions of poly(vinyl) alcohol (PVOH) 39 KDa (P1), PVOH 197 KDa (P2), carboxymethylcellulose (CMC) 395 KDa (C1), and CMC 725 KDa (C2) were prepared. Texture analysis and Dynamic Mechanical Analysis (DMA) were used to assess film tack. Petri dish and drop methods were used to assess disintegration time. A human panel of 24 healthy young adults was employed to identify end-user acceptability criteria of the four study film samples. Texture analysis data of ODF tack were not found to be in agreement with the in vivo perceived stickiness in the mouth. However, measurement of the area under the adhesive force curve obtained by DMA correlated with in vivo perceived stickiness data for all samples. The disintegration times obtained by drop method were more comparable to human panel data than the petri dish method. Hence DMA and drop methods proved to be promising methodologies for the prediction of the end-user acceptability. The type and molecular weight of the film-forming polymer had a strong influence on stickiness perception, whereas only polymeric molecular weight influenced perceived disintegration time. The human panel study showed that Participant Reported Outcomes (PROs) for the perceived stickiness in the mouth and disintegration time of test films received significantly different scores between samples, and thus were identified as the key attributes with the potential to affect the end-user acceptability. ODF stickiness and disintegration time should therefore be evaluated at an early stage of the drug product design. Copyright © 2018 Elsevier B.V. All rights reserved.

Antimycobacterial activity assessment of three ethnobotanical plants against Mycobacterium Tuberculosis: An In Vitro study.

PubMed

Arjomandzadegan, Mohammad; Emami, Navid; Habibi, Ghasem; Farazi, Ali Asghar; Kahbazi, Manijeh; Sarmadian, Hossein; Jabbari, Mansooreh; Hosseini, Hossein; Ramezani, Mona

2016-12-01

Resistances to herbal medicines are still not defined and finding natural remedies against drug resistant Mycobacterium tuberculosis (MTB) has research priority. The antimycobacterial susceptibility method for herbal extracts is unclearly defined and there is no standard method for assessment of the materials against bacteria. In the present study, time kill of three medicinal plants was determined against MTB. The clinical isolate of MTB from a patient who harbored confirmed tuberculosis was used in the study. Aqueous extracts of Aloe vera leaves, mint, and Hypericum perforatum were prepared using reflux distillation. Disk diffusion methods were conducted in Petri dishes and McCartney bottles containing Löwenstein-Jensen medium to measure the sensitivity of plant extracts in serial concentrations of 0.25-8mg/mL. A pour plate method was performed by mixing 0.7mL of each concentration of extract in 5mL Löwenstein-Jensen medium followed by surface culturing of MTB fresh cells. The time kill method was conducted by bacterial suspension in equal amounts of the extract and viable evaluation in fresh culture at the beginning, and at 24-h, 48-h, 72-h, and 1-week intervals. All cultures were incubated at 37°C for 4weeks. Inoculum concentrations were considered as a variable. The zones of inhibition of A. vera, H. perforatum, and mint extracts in the disk diffusion method in McCartney bottles were 60mm, 41mm, and zero, respectively, but Petri dishes did not have repeatable results. In the pour plate method, an extract concentration up to 1mg/mL could inhibit cell growth. In mint extract, colony forming was four times more than the others at 0.5mg/mL. Time kill of 95% of cells occurred when exposed to extracts of A. vera and H. perforatum separately, but was 50% in 24 h and 20% in 10 min. The time kill for mint was 95% in 1week. The results give some scientific basis to the use of plant extracts for growth control of MTB cells. Clinical trials are recommended for assessment of the extract as complementary medicine, as well as for antisepsis. Copyright © 2016.

Catering Gluten-Free When Simultaneously Using Wheat Flour.

PubMed

Miller, Kathryn; McGough, Norma; Urwin, Heidi

2016-02-01

A European law on gluten-free (GF) labeling came into force in 2012, covering foods sold prepacked and in food service establishments, and a similar U.S. Food and Drug Administration (FDA) regulation covers GF labeling from August 2014. Gluten is found in the grains wheat, rye, and barley. A common source of gluten in the kitchen is wheat flour. This research aimed to determine variables that have a significant effect on gluten contamination in commercial kitchens when wheat flour is in use and to establish controls necessary to assure GF production. A pilot study was used to test the following hypotheses: (i) increasing duration of exposure to wheat flour would increase gluten contamination, (ii) increasing distance between the site of preparation and the site of wheat flour would reduce gluten contamination, (iii) the use of a ventilation hood would decrease gluten contamination, and (iv) the use of a barrier segregating the site of preparation of a GF meal and the use of wheat flour would decrease gluten contamination. Petri dishes containing GF rice pudding were placed in three directions at increasing distances (0.5 to 2 m) from a site of wheat flour use. A barrier was in place between a third of samples and the site of wheat flour. After wheat flour was handled for 0.5 and 4.0 h, petri dishes were sealed and the contents were analyzed for gluten. The experiment was duplicated with the ventilation hood on and off. The pilot study revealed that a distance of 2 m from the use of wheat flour was required to control gluten contamination at ≤20 ppm if wheat flour had been in use for 4.0 h. The identified control of distance was tested in five different study sites. In each of the study sites, a test meal was prepared a minimum of 2 m away from the site of wheat flour use. Although kitchens vary and must be considered individually, the established control of a minimum 2 m distance, along with good hygiene practices, was found to be effective in preparing GF meals at all five study sites.

Cadmium translocation by contractile roots differs from that in regular, non-contractile roots

PubMed Central

Lux, Alexander; Lackovič, Andrej; Van Staden, Johannes; Lišková, Desana; Kohanová, Jana; Martinka, Michal

2015-01-01

Background and Aims Contractile roots are known and studied mainly in connection with the process of shrinkage of their basal parts, which acts to pull the shoot of the plant deeper into the ground. Previous studies have shown that the specific structure of these roots results in more intensive water uptake at the base, which is in contrast to regular root types. The purpose of this study was to find out whether the basal parts of contractile roots are also more active in translocation of cadmium to the shoot. Methods Plants of the South African ornamental species Tritonia gladiolaris were cultivated in vitro for 2 months, at which point they possessed well-developed contractile roots. They were then transferred to Petri dishes with horizontally separated compartments of agar containing 50 µmol Cd(NO3)2 in the region of the root base or the root apex. Seedlings of 4-d-old maize (Zea mays) plants, which do not possess contractile roots, were also transferred to similar Petri dishes. The concentrations of Cd in the leaves of the plants were compared after 10 d of cultivation. Anatomical analyses of Tritonia roots were performed using appropriately stained freehand cross-sections. Key Results The process of contraction required specific anatomical adaptation of the root base in Tritonia, with less lignified and less suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics were accompanied by more intensive translocation of Cd ions from the basal part of contractile roots to the leaves than from the apical–subapical root parts. The opposite effects were seen in the non-contractile roots of maize, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part. Conclusions The specific characteristics of contractile roots may have a significant impact on the uptake of ions, including toxic metals from the soil surface layers. This may be important for plant nutrition, for example in the uptake of nutrients from upper soil layers, which are richer in humus in otherwise nutrient-poor soils, and also has implications for the uptake of surface-soil pollutants. PMID:25939652

Flexible Sheet-Type Sensor for Noninvasive Measurement of Cellular Oxygen Metabolism on a Culture Dish.

PubMed

Kojima, Mari; Takehara, Hiroaki; Akagi, Takanori; Shiono, Hirofumi; Ichiki, Takanori

2015-01-01

A novel flexible sensor was developed for the noninvasive oxygen metabolism measurement of cultivated cells and tissues. This device is composed of a transparent double-layered polymer sheet of ethylene-vinyl alcohol (EVOH) and poly(dimethylsiloxane) (PDMS) having an array of microhole structures of 90 μm diameter and 50 μm depth on its surface. All the microhole structures were equipped with a 1-μm-thick optical chemical sensing layer of platinum porphyrin-fluoropolymer on their bottom. The three-dimensional microstructures of the sensor were fabricated by a newly developed simple and low-cost production method named self-aligned hot embossing. The device was designed to be attached slightly above the cells cultivated on a dish to form a temporarily closed microspace over the target cells during measurement. Since the change in oxygen concentration is relatively fast in the microcompartmentalized culture medium, a rapid evaluation of the oxygen consumption rate is possible by measuring the phosphorescence lifetime of the platinum porphyrin-fluoropolymer. The combined use of the device and an automated optical measurement system enabled the high-throughput sensing of cellular oxygen consumption (100 points/min). We monitored the oxygen metabolism of the human breast cancer cell line MCF7 on a Petri dish and evaluated the oxygen consumption rate to be 0.72 ± 0.12 fmol/min/cell. Furthermore, to demonstrate the utility of the developed sensing system, we demonstrated the mapping of the oxygen consumption rate of rat brain slices and succeeded in visualizing a clear difference among the layer structures of the hippocampus, i.e., the cornu ammonis (CA1 and CA3) and dentate gyrus (DG).

Microwave effects on isolated chick embryo hearts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caddemi, A.; Tamburello, C.C.; Zanforlin, L.

1986-01-01

This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to themore » modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the heart.« less

Genetic Tools for Self-Organizing Culture of Mouse Embryonic Stem Cells via Small Regulatory RNA-Mediated Technologies, CRISPR/Cas9, and Inducible RNAi.

PubMed

Takata, Nozomu; Sakakura, Eriko; Sakuma, Tetsushi; Yamamoto, Takashi

2017-01-01

Approaches to investigate gene functions in experimental biology are becoming more diverse and reliable. Furthermore, several kinds of tissues and organs that possess their original identities can be generated in petri dishes from stem cells including embryonic, adult and induced pluripotent stem cells. Researchers now have several choices of experimental methods and their combinations to analyze gene functions in various biological systems. Here, as an example we describe one of the better protocols, which combines three-dimensional embryonic stem cell culture with small regulatory RNA-mediated technologies, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), and inducible RNA interference (RNAi). This protocol allows investigation of genes of interest to better understand gene functions in target tissues (or organs) during in vitro development.

Entrapment of hepatocyte spheroids in a hollow fiber bioreactor as a potential bioartificial liver.

PubMed

Wu, F J; Peshwa, M V; Cerra, F B; Hu, W S

1995-01-01

A bioartificial liver (BAL) employing xenogeneic hepatocytes has been developed as a potential interim support for patients in hepatic failure. For application in human therapy, the BAL requires a substantial increase in liver-specific functions. Cultivation of hepatocytes as spheroids leads to enhanced liver specific functions. We explored the possibility of entrapping spheroids into the BAL in order to improve device performance. Rat hepatocyte spheroids were entrapped in collagen gel within the lumen fibers of the BAL. The morphology and ultrastructure of collagen-entrapped spheroids resembled those of suspended spheroids formed on petri dishes. Albumin synthesis and P-450 enzyme activity were measured as markers of liver specific functions of spheroids entrapped in the BAL. At least a 4-fold improvement in these functions was observed compared to BAL devices entrapped with dispersed hepatocytes in collagen gels.

Numerical modelling and experimental study of liquid evaporation during gel formation

NASA Astrophysics Data System (ADS)

Pokusaev, B. G.; Khramtsov, D. P.

2017-11-01

Gels are promising materials in biotechnology and medicine as a medium for storing cells for bioprinting applications. Gel is a two-phase system consisting of solid medium and liquid phase. Understanding of a gel structure evolution and gel aging during liquid evaporation is a crucial step in developing new additive bioprinting technologies. A numerical and experimental study of liquid evaporation was performed. In experimental study an evaporation process of an agarose gel layer located on Petri dish was observed and mass difference was detected using electronic scales. Numerical model was based on a smoothed particle hydrodynamics method. Gel in a model was represented as a solid-liquid system and liquid evaporation was modelled due to capillary forces and heat transfer. Comparison of experimental data and numerical results demonstrated that model can adequately represent evaporation process in agarose gel.

Self-folding micropatterned polymeric containers.

PubMed

Azam, Anum; Laflin, Kate E; Jamal, Mustapha; Fernandes, Rohan; Gracias, David H

2011-02-01

We demonstrate self-folding of precisely patterned, optically transparent, all-polymeric containers and describe their utility in mammalian cell and microorganism encapsulation and culture. The polyhedral containers, with SU-8 faces and biodegradable polycaprolactone (PCL) hinges, spontaneously assembled on heating. Self-folding was driven by a minimization of surface area of the liquefying PCL hinges within lithographically patterned two-dimensional (2D) templates. The strategy allowed for the fabrication of containers with variable polyhedral shapes, sizes and precisely defined porosities in all three dimensions. We provide proof-of-concept for the use of these polymeric containers as encapsulants for beads, chemicals, mammalian cells and bacteria. We also compare accelerated hinge degradation rates in alkaline solutions of varying pH. These optically transparent containers resemble three-dimensional (3D) micro-Petri dishes and can be utilized to sustain, monitor and deliver living biological components.

Biocidal action of ozone-treated polystyrene surfaces on vegetative and sporulated bacteria

NASA Astrophysics Data System (ADS)

Mahfoudh, Ahlem; Barbeau, Jean; Moisan, Michel; Leduc, Annie; Séguin, Jacynthe

2010-03-01

Surfaces of materials can be modified to ensure specific interaction features with microorganisms. The current work discloses biocidal properties of polystyrene (PS) Petri-dish surfaces that have been exposed to a dry gaseous-ozone flow. Such treated PS surfaces are able to inactivate various species of vegetative and sporulated bacteria on a relatively short contact time. Denaturation of proteins seems likely based on a significant loss of enzymatic activity of the lysozyme protein. Characterization of these surfaces by atomic-force microscopy (AFM), Fourier-transform infra-red (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) reveals specific structural and chemical modifications as compared to untreated PS. Persistence of the biocidal properties of these treated surfaces is observed. This ozone-induced process is technically simple to achieve and does not require active precursors as in grafting.

Magnetic Luminescent Porous Silicon Microparticles for Localized Delivery of Molecular Drug Payloads

PubMed Central

Gu, Luo; Park, Ji-Ho; Duong, Kim H.; Ruoslahti, Erkki; Sailor, Michael J.

2011-01-01

Magnetic manipulation, fluorescent tracking, and localized delivery of a drug payload to cancer cells in vitro is demonstrated, using nanostructured porous silicon microparticles as a carrier. The multifunctional microparticles are prepared by electrochemical porosification of a silicon wafer in a hydrofluoric acid-containing electrolyte, followed by removal and fracture of the porous layer into particles using ultrasound. The intrinsically luminescent particles are loaded with superparamagnetic iron oxide nanoparticles and the anti-cancer drug doxorubicin. The drug-containing particles are delivered to human cervical cancer (HeLa) cells in vitro, under the guidance of a magnetic field. The high concentration of particles in the proximity of the magnetic field results in a high concentration of drug being released in that region of the Petri dish, and localized cell death is confirmed by cellular viability assay (Calcein AM). PMID:20814923

Magnetic luminescent porous silicon microparticles for localized delivery of molecular drug payloads.

PubMed

Gu, Luo; Park, Ji-Ho; Duong, Kim H; Ruoslahti, Erkki; Sailor, Michael J

2010-11-22

Magnetic manipulation, fluorescent tracking, and localized delivery of a drug payload to cancer cells in vitro is demonstrated, using nanostructured porous silicon microparticles as a carrier. The multifunctional microparticles are prepared by electrochemical porosification of a silicon wafer in a hydrofluoric acid-containing electrolyte, followed by removal and fracture of the porous layer into particles using ultrasound. The intrinsically luminescent particles are loaded with superparamagnetic iron oxide nanoparticles and the anti-cancer drug doxorubicin. The drug-containing particles are delivered to human cervical cancer (HeLa) cells in vitro, under the guidance of a magnetic field. The high concentration of particles in the proximity of the magnetic field results in a high concentration of drug being released in that region of the Petri dish, and localized cell death is confirmed by cellular viability assay (Calcein AM).

Characteristics and Efficacy of a Sterile Hyphomycete (ARF18), a New Biocontrol Agent for Heterodera glycines and Other Nematodes

PubMed Central

Kim, D. G.; Riggs, R. D.

1991-01-01

A filamentous, nonsporulating fungus, designated Arkansas Fungus 18 (ARF18), was isolated from 9 of 95 populations of Heterodera glycines, the soybean cyst nematode, in Arkansas. In petri dishes, ARF18 parasitized 89% of H. glycines eggs in cysts. The fungus also infected eggs of Meloidogyne incognita and eggs in cysts of Cactodera betulae, H. graminophila, H. lespedezae, H. leuceilyma, H. schachtii, and H. trifolii. In pot tests, reproduction of SCN was 70% less in untreated field soil that was naturally infested by ARF18 than in autoclaved field soil. Although ARF18 grew well at 25 C on cornmeal agar over a wide pH range, it did not sporulate on 28 media and thus could not be identified to genus or species. PMID:19283127

Proton beam writing of microstructures in Agar gel for patterned cell growth

NASA Astrophysics Data System (ADS)

Larisch, Wolfgang; Koal, Torsten; Werner, Ronald; Hohlweg, Marcus; Reinert, Tilo; Butz, Tilman

2011-10-01

A rather useful prerequisite for many biological and biophysical studies, e.g., for cell-cell communication or neuronal networks, is confined cell growth on micro-structured surfaces. Solidified Agar layers have smooth surfaces which are electrically neutral and thus inhibit receptor binding and cell adhesion. For the first time, Agar microstructures have been manufactured using proton beam writing (PBW). In the irradiated Agar material the polysaccharides are split into oligosaccharides which can easily be washed off leaving Agar-free areas for cell adhesion. The beam diameter of 1 μm allows the fabrication of compartments accommodating single cells which are connected by micrometer-sized channels. Using the external beam the production process is very fast. Up to 50 Petri dishes can be produced per day which makes this technique very suitable for biological investigations which require large throughputs.

Reducing the risk of surgical site infection: a case controlled study of contamination of theatre clothing.

PubMed

Sivanandan, Indu; Bowker, Karen E; Bannister, Gordon C; Soar, Jasmeet

2011-02-01

Surgical site infections are one of the most important causes of healthcare associated infections (HCAI), accounting for 20% of all HCAIs. Surgical site infections affect 1% of joint replacement operations. This study was designed to assess whether theatre clothing is contaminated more inside or outside the theatre suite. Petri dishes filled with horse blood agar were pressed on theatre clothes at 0, 2, 4, 6 and 8 hours to sample bacterial contamination in 20 doctors whilst working in and outside the theatre suite. The results showed that there was greater bacterial contamination when outside the theatre suite at 2 hours. There were no differences in the amount of contamination at 4, 6 and 8 hours. This study suggests that the level of contamination of theatre clothes is similar both inside and outside the theatre setting.

Quantitative estimation of dust fall and smoke particles in Quetta Valley*

PubMed Central

Sami, Muhammad; Waseem, Amir; Akbar, Sher

2006-01-01

Tightening of air quality standards for populated urban areas has led to increasing attention to assessment of air quality management areas, where violation of air quality standards occurs, and development of control strategies to eliminate such violation of air quality standards. The Quetta urban area is very densely built and has heavy motorized traffic. The increase of emissions mainly from traffic and industry are responsible for the increase in atmospheric pollution levels during the last years. The dust examined in the current study was collected by both deposit gauge and Petri dish methods at various sites of Quetta Valley. Smoke particles were obtained by bladder method from the exhausts of various types of motor vehicles. The concentration of lead found in the smoke ranged from 1.5×10−6 to 4.5×10−6. PMID:16773727

Tendon cell outgrowth rates and morphology associated with kevlar-49.

PubMed

Zimmerman, M; Gordon, K E

1988-12-01

A rat tendon cell model was used to evaluate the in vitro biocompatibility of kevlar-49. The cell response to kevlar was compared to carbon AS-4 and nylon sutures. Three trials were run and cell growth rates were statistically similar for all the materials tested. A separate experiment was conducted in which the same fiber materials were placed in the same Petri dish. Again, the rates were similar for each material. Finally, the cells were observed with a scanning electron microscope, and the three classic cell morphologies associated with this tendon cell model were observed. Also, cellular attachment to the fiber and cellular encapsulation of the fiber were identical for the three materials tested. Kevlar-49 proved to be comparable to carbon AS4 and nylon sutures in terms of cellular response and cell outgrowth rates.

Cell Sheet Stiffness Sensing without taking out from culture liquid.

PubMed

Uchida, Ryohei; Tanaka, Nobuyuki; Higashimori, Mitsuru; Tadakuma, Kenjiro; Kaneko, Makoto; Kondo, Makoto; Yamato, Masayuki

2010-01-01

Stiffness could be an important index for evaluating the vitality of cell sheet. This paper challenges the measurement of stiffness of transparent cell sheet in culture liquid without taking it out from petri dish. The system is composed of a micro air nozzle for supplying an air jet and a regular reflective type laser sensor for measuring the the deformation of transparent cell sheet. This system is called as Cell Sheet Stiffness Sensing system (CS(3) system). When an air jet is given to a cell sheet in culture liquid, it pushes away the liquid toward the outer direction at initial phase and reaches the surface of cell sheet. Without any switching motion, the air jet continuously imparts a force to the surface of cell sheet so that the sensor can measure the stiffness of the cell sheet.

Fungicidal activity of silver nanoparticles against Alternaria brassicicola

NASA Astrophysics Data System (ADS)

Gupta, Deepika; Chauhan, Pratima

2016-04-01

This work highlighted the fungicidal properties of silver nanoparticles against Alternaria brassicicola. Alternaria brassicicola causes Black spot of Cauliflower, radish, cabbage, kale which results in sever agricultural loss. We treat the synthesised silver nanoparticles (AgNPs) of 10, 25, 50, 100 and 110 ppm concentrations against Alternaria brassicicola on PDA containing Petri dish. We calculated inhibitory rate (%) in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. Treatment with 100ppm AgNPs resulted in maximum inhibition of Alternaria brassicicola i.e.92.2%. 110ppm of AgNPS also shows the same result, therefore 100ppm AgNPs was treated as optimize concentration. AgNPs effectively inhibited the growth of a Alternaria brassicicola, which suggests that AgNPs could be used as fungicide in plant disease management. Further research and development are necessary to translate this technology into plant disease management strategies.

Designing electrical stimulated bioreactors for nerve tissue engineering

NASA Astrophysics Data System (ADS)

Sagita, Ignasius Dwi; Whulanza, Yudan; Dhelika, Radon; Nurhadi, Ibrahim

2018-02-01

Bioreactor provides a biomimetic ecosystem that is able to culture cells in a physically controlled system. In general, the controlled-parameters are temperature, pH, fluid flow, nutrition flow, etc. In this study, we develop a bioreactor that specifically targeted to culture neural stem cells. This bioreactor could overcome some limitations of conventional culture technology, such as petri dish, by providing specific range of observation area and a uniform treatment. Moreover, the microfluidic bioreactor, which is a small-controlled environment, is able to observe as small number of cells as possible. A perfusion flow is applied to mimic the physiological environment in human body. Additionally, this bioreactor also provides an electrical stimulation which is needed by neural stem cells. In conclusion, we found the correlation between the induced shear stress with geometric parameters of the bioreactor. Ultimately, this system shall be used to observe the interaction between stimulation and cell growth.

An extension of the Coconut Cream Agar method to screen Penicillium citrinum isolates for citrinin production.

PubMed

Mohamed, S; Flint, S; Palmer, J; Fletcher, G C; Pitt, J I

2013-09-01

A simple and rapid screening method was developed for the detection of citrinin in fungal cultures using Coconut Cream Agar (CCA) described previously for detecting aflatoxin and ochratoxin A. Fifteen isolates of Penicillium citrinum were inoculated onto CCA and incubated at 25 and 30°C for 10 days. All isolates produced a distinct yellow green fluorescence on CCA when the reverse side of the agar plates were viewed under long wavelength UV light. Detection was optimal at 25°C after four to 5 days of incubation. Isolates positive by the CCA method also tested positive for citrinin production by the TLC agar plug method after growth on CCA, Czapek yeast extract agar and yeast extract sucrose agar. Control cultures were negative by both methods, indicating that the CCA Petri dish method was suitable for screening cultures for citrinin production. © 2013 The Society for Applied Microbiology.

Effect of the entomopathogenic fungus Lecanicillium muscariumon the predatory mite Phytoseiulus persimilis as a non-target organism.

PubMed

Donka, András; Sermann, Helga; Büttner, Carmen

2008-01-01

In biological control, different benefit organisms have to combine for an effective management. If entomopathogenic fungi will be integrated, than it has to be considered also the effect on non-target organisms Like beneficial arthropods. Because of the high importance of predatory mite Phytoseiulus persimilis in biological control it was to determine side effects of Leconicillium muscarium on this species. In two standardised biotests in petri dish and on plants (P. vulgaris) individuals were dipped in suspension or set down on leafs after spraying with L. muscarium at different spore density. Results indicate pathogenicity for the predatory mite in principle. But the dimension of infection risk decrease, all the more conditions approach to practical sequence. Under practical conditions on plants and in practical relevant concentration of 10(6) and 10(7) sp./ml no risk is to expect on the plant.

The effect of linalool on second-stage juveniles of the potato cyst nematodes Globodera rostochiensis and G. pallida.

PubMed

Būda, Vincas; Cepulytė-Rakauskienė, Rasa

2011-09-01

Linalool is either a toxic compound to a few species of plant parasitic nematodes or attractive to entomopathogenic nematodes. This compound is produced and emitted by several host plants of Globodera rostochiensis and G. pallida, the potato cyst nematodes (PCN). With the aim to reveal the effect of linalool on PCN, laboratory assays were carried out. Survival of PCN second-stage juveniles (J2s) in water + linalool control did not differ; thus, proving linalool to be nontoxic to PCN. Behavioral assays carried out in Petri dishes revealed attractiveness in the form of positive response of J2s of both PCN species towards linalool. Based on these behavioral assays, sensitivity to linalool of G. rostochiensis J2s was higher compared with that of G. pallida J2s. Linalool is the first compound of plant origin to elicit positive response in both PCN species.

Four reversible and reconfigurable structures for three-phase emulsions: extended morphologies and applications

NASA Astrophysics Data System (ADS)

Ge, Xue-Hui; Geng, Yu-Hao; Zhang, Qiao-Chu; Shao, Meng; Chen, Jian; Luo, Guang-Sheng; Xu, Jian-Hong

2017-02-01

Here in this article, we classify and conclude the four morphologies of three-phase emulsions. Remarkably, we achieve the reversible transformations between every shape. Through theoretical analysis, we choose four liquid systems to form these four morphologies. Then monodispersed droplets with these four morphologies are formed through a microfluidic device and captured in a petri-dish. By replacing their ambient solution of the captured emulsions, in-situ morphology transformations between each shape are achieved. The process is well recorded through photographs and videos and they are systematical and reversible. Finally, we use the droplets structure to form an on-off switch to start and shut off the evaporation of one volatile phase to achieve the process monitoring. This could be used to initiate and quench a reaction, which offers a novel idea to achieve the switchable and reversible reaction control in multiple-phase reactions.

Studying Cancer Stem Cell Dynamics on PDMS Surfaces for Microfluidics Device Design

PubMed Central

Zhang, Weijia; Choi, Dong Soon; Nguyen, Yen H.; Chang, Jenny; Qin, Lidong

2013-01-01

This systematic study clarified a few interfacial aspects of cancer cell phenotypes on polydimethylsiloxane (PDMS) substrates and indicated that the cell phenotypic equilibrium greatly responds to cell-to-surface interactions. We demonstrated that coatings of fibronectin, bovine serum albumin (BSA), or collagen with or without oxygen-plasma treatments of the PDMS surfaces dramatically impacted the phenotypic equilibrium of breast cancer stem cells, while the variations of the PDMS elastic stiffness had much less such effects. Our results showed that the surface coatings of collagen and fibronectin on PDMS maintained breast cancer cell phenotypes to be nearly identical to the cultures on commercial polystyrene Petri dishes. The surface coating of BSA provided a weak cell-substrate adhesion that stimulated the increase in stem-cell-like subpopulation. Our observations may potentially guide surface modification approaches to obtain specific cell phenotypes. PMID:23900274

Effect of the Entomogenous Nematode Nemplectana carpocapsae on the Tachinid Parasite Compsilura concinnata (Diptera: Tachinidae)

PubMed Central

Kaya, Harry K.

1984-01-01

The entomogenous nematode Neoaplectana carpocapsae and its associated bacterium, Xenorhabdus nematophilus, could not infect the pupal stage of the tachinid Compsilura concinnata through the puparium. N. carpocapsae had an adverse effect on 1-, 2- and 3-day-old C. concinnata larvae within the armyworm host in petri dish tests. All 1-day-old larvae treated with nematodes died in their hosts, whereas 61% and 69% of 2- and 3-day-old larvae treated with nematodes, respectively, died. However, the survivors developed to adults. Nine to thirty-seven percent of adult tachinids which emerged from nematode-treated soil (50 nematodes/cm²) were infected with N. carpocapsae. The nematode adversely affects C. concinnata directly by the frank infection of the tachinid and indirectly by causing the premature death of the host which results in tachinid death. PMID:19295866

Potential of natural products and their derivatives to control Formosan subterranean termites (Isoptera: Rhinotermitidae).

PubMed

Raina, Ashok; Bedoukian, Robert; Florane, Chris; Lax, Alan

2012-10-01

Twenty-nine natural products and their derivatives were tested for both contact and vapor toxicity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Five natural products at 0.5% (wt:wt) in petri dish contact assay caused 100% mortality within 3 d. In vapor form, only three chemicals (styrallyl alcohol, 2-phenyl-2-propanol, and l-carvone) at 0.25 microl/liter air caused > 90% mortality in 3 d when tested on exposed termites: However, when termites were shielded by wood and soil, only one chemical, tetrahydrocarvone at 25 microl/liter air caused 100% mortality in 2 d. Preliminary test with termites in carton nests, exposed to tetrahydrocarvone vapor in desiccators, resulted in an average of 98.6% mortality in 7 d. With further development in the method of delivery, this chemical may be very useful in fumigating confined areas of termite infestation.

Fabricating nanowire devices on diverse substrates by simple transfer-printing methods.

PubMed

Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

2010-06-01

The fabrication of nanowire (NW) devices on diverse substrates is necessary for applications such as flexible electronics, conformable sensors, and transparent solar cells. Although NWs have been fabricated on plastic and glass by lithographic methods, the choice of device substrates is severely limited by the lithographic process temperature and substrate properties. Here we report three new transfer-printing methods for fabricating NW devices on diverse substrates including polydimethylsiloxane, Petri dishes, Kapton tapes, thermal release tapes, and many types of adhesive tapes. These transfer-printing methods rely on the differences in adhesion to transfer NWs, metal films, and devices from weakly adhesive donor substrates to more strongly adhesive receiver substrates. Electrical characterization of fabricated NW devices shows that reliable ohmic contacts are formed between NWs and electrodes. Moreover, we demonstrated that Si NW devices fabricated by the transfer-printing methods are robust piezoresistive stress sensors and temperature sensors with reliable performance.

Antimicrobial activity of bark extracts of Syzygium jambos (L.) alston (Myrtaceae).

PubMed

Djipa, C D; Delmée, M; Quetin-Leclercq, J

2000-07-01

Syzygium jambos (L.) Alston (Myrtaceae) is a widespread medicinal plant traditionally used in sub-Saharan Africa to treat infectious diseases. Acetone and aqueous extracts from the bark of S. jambos were tested for antimicrobial activity in vitro by the agar dilution method in petri dishes. Both extracts showed some activity against the tested micro-organisms. They proved to be particularly effective on Staphylococcus aureus, Yersinia enterocolitica and coagulase negative staphylococci among which Staphylococcus hominis, Staphylococcus cohnii and Staphylococcus warneri. These properties seem to be related to the high tannin content of S. jambos extracts (77 and 83% for the aqueous and acetone extracts, respectively, determined according to the European Pharmacopoeia method) which were generally more active than Hamamelis virginiana, Krameria triandra, Alchemilla vulgaris and Rubus fruticosus extracts containing 48, 44, 46 and 28% tannins, respectively. Furthermore, elimination of tannins totally suppressed these antimicrobial activities.

Cell-based dose responses from open-well microchambers.

PubMed

Hamon, Morgan; Jambovane, Sachin; Bradley, Lauren; Khademhosseini, Ali; Hong, Jong Wook

2013-05-21

Cell-based assays play a critical role in discovery of new drugs and facilitating research in cancer, immunology, and stem cells. Conventionally, they are performed in Petri dishes, tubes, or well plates, using milliliters of reagents and thousands of cells to obtain one data point. Here, we are introducing a new platform to realize cell-based assay capable of increased throughput and greater sensitivity with a limited number of cells. We integrated an array of open-well microchambers into a gradient generation system. Consequently, cell-based dose responses were examined with a single device. We measured IC50 values of three cytotoxic chemicals, Triton X-100, H2O2, and cadmium chloride, as model compounds. The present system is highly suitable for the discovery of new drugs and studying the effect of chemicals on cell viability or mortality with limited samples and cells.

Does scavenging extend the host range of entomopathogenic nematodes (Nematoda: Steinernematidae)?

PubMed

Půza, Vladimír; Mrácek, Zdenĕk

2010-05-01

Living and freeze-killed natural and laboratory hosts, with different susceptibility to entomopathogenic nematodes, were exposed to the larvae of Steinernema affine and Steinernema kraussei in two different experimental arenas (Eppendorf tubes, Petri dishes), and the success of the colonisation and eventual progeny production were observed. Both nematodes were able to colonise both living and dead larvae of Galleria mellonella (Lepidoptera) and adult Blatella germanica (Blattodea) even though the progeny production in dead hosts was lower on average. Living carabid beetles, Poecilus cupreus, and elaterid larvae (Coleoptera) were resistant to the infection, however, both nematodes were able to colonise and multiply in several dead P. cupreus and in a majority of dead elaterid larvae. By scavenging, EPNs can utilise cadavers of insects that are naturally resistant to EPN infection, and so broaden their host range. (c) 2010 Elsevier Inc. All rights reserved.

Aspergillus 6V4, a Strain Isolated from Manipueira, Produces High Amylases Levels by Using Wheat Bran as a Substrate

PubMed Central

Celestino, Jessyca dos Reis; Duarte, Ana Caroline; Silva, Cláudia Maria de Melo; Sena, Hellen Holanda; Ferreira, Maria do Perpétuo Socorro Borges Carriço; Mallmann, Neila Hiraishi; Lima, Natacha Pinheiro Costa; Tavares, Chanderlei de Castro; de Souza, Rodrigo Otávio Silva; Souza, Érica Simplício; Souza, João Vicente Braga

2014-01-01

The aim of this study was screening fungi strains, isolated from manipueira (a liquid subproduct obtained from the flour production of Manihot esculenta), for amylases production and investigating production of these enzymes by the strain Aspergillus 6V4. The fungi isolated from manipueira belonged to Ascomycota phylum. The strain Aspergillus 6V4 was the best amylase producer in the screening assay of starch hydrolysis in petri dishes (ASHPD) and in the assay in submerged fermentation (ASbF). The strain Aspergillus 6V4 produced high amylase levels (335 UI/L) using wheat bran infusion as the exclusive substrate and the supplementation of this substrate with peptone decreased the production of this enzyme. The moisture content of 70% was the best condition for the production of Aspergillus 6V4 amylases (385 IU/g) in solid state fermentation (SSF). PMID:24724017

Health hazard evaluation report HETA 84-198-1560, Division of Public Health Laboratories, State of Ohio, Columbus, Ohio. [Ethylene oxide and organic-solvent vapors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrens, V.; Burroughs, G.E.

1985-02-01

Breathing-zone and environmental samples were analyzed for ethylene oxide and organic-solvent vapors at the Public Health Laboratory, State of Ohio, Columbus, Ohio, on March 26 and 27, 1984. The evaluation was requested because of employee complaints of mucous membrane and skin irritation while they poured gonorrhea culture media into petri dishes that had been sterilized with ethylene oxide. The authors conclude that the environmental cause of the health problems cannot be determined due to the lack of symptoms on the days of the survey. Without taking measurements on the exact day when conspicuous symptoms occur, it is difficult to determinemore » the source of the problem. General recommendations include checking the general air circulation in the media laboratory and encouraging employees to wear gloves that protect hands and wrists while pouring culture media.« less

Simultaneous Scanning Ion Conductance Microscopy and Atomic Force Microscopy with Microchanneled Cantilevers

NASA Astrophysics Data System (ADS)

Ossola, Dario; Dorwling-Carter, Livie; Dermutz, Harald; Behr, Pascal; Vörös, János; Zambelli, Tomaso

2015-12-01

We combined scanning ion conductance microscopy (SICM) and atomic force microscopy (AFM) into a single tool using AFM cantilevers with an embedded microchannel flowing into the nanosized aperture at the apex of the hollow pyramid. An electrode was positioned in the AFM fluidic circuit connected to a second electrode in the bath. We could thus simultaneously measure the ionic current and the cantilever bending (in optical beam deflection mode). First, we quantitatively compared the SICM and AFM contact points on the approach curves. Second, we estimated where the probe in SICM mode touches the sample during scanning on a calibration grid and applied the finding to image a network of neurites on a Petri dish. Finally, we assessed the feasibility of a double controller using both the ionic current and the deflection as input signals of the piezofeedback. The experimental data were rationalized in the framework of finite elements simulations.

Survival of influenza A virus on contaminated student clothing

PubMed Central

IKEDA, KEIKO; TSUJIMOTO, KAZUKO; SUZUKI, YUKIKO; KOYAMA, AUGUSTINE HAJIME

2015-01-01

The role of contaminated clothing in the transmission of influenza A virus during an epidemic period was investigated by examining the recovery of infectious influenza virus from experimentally virus-contaminated clothing, which had been subejected to routine wearing and washing for several months or years. The amount of infectious virus recovered from the nine types of clothing decreased with time and was shown to differ widely between clothing samples, when the contaminated clothing samples were maintained in uncovered glass Petri dishes in a safety cabinet under air blowing. These results indicate a dependence of virus transmissibility on the nature of the contaminated clothes. The difference in recovery was shown to have no significant correlation with the thickness or the materials of the clothing; however, a correlation was observed with the residual amount of water in the deposited virus preparation on the test clothing. PMID:25780410

Growth in spaceflight hardware results in alterations to the transcriptome and proteome

NASA Astrophysics Data System (ADS)

Basu, Proma; Kruse, Colin P. S.; Luesse, Darron R.; Wyatt, Sarah E.

2017-11-01

The Biological Research in Canisters (BRIC) hardware has been used to house many biology experiments on both the Space Transport System (STS, commonly known as the space shuttle) and the International Space Station (ISS). However, microscopic examination of Arabidopsis seedlings by Johnson et al. (2015) indicated the hardware itself may affect cell morphology. The experiment herein was designed to assess the effects of the BRIC-Petri Dish Fixation Units (BRIC-PDFU) hardware on the transcriptome and proteome of Arabidopsis seedlings. To our knowledge, this is the first transcriptomic and proteomic comparison of Arabidopsis seedlings grown with and without hardware. Arabidopsis thaliana wild-type Columbia (Col-0) seeds were sterilized and bulk plated on forty-four 60 mm Petri plates, of which 22 were integrated into the BRIC-PDFU hardware and 22 were maintained in closed containers at Ohio University. Seedlings were grown for approximately 3 days, fixed with RNAlater® and stored at -80 °C prior to RNA and protein extraction, with proteins separated into membrane and soluble fractions prior to analysis. The RNAseq analysis identified 1651 differentially expressed genes; MS/MS analysis identified 598 soluble and 589 membrane proteins differentially abundant both at p < .05. Fold enrichment analysis of gene ontology terms related to differentially expressed transcripts and proteins highlighted a variety of stress responses. Some of these genes and proteins have been previously identified in spaceflight experiments, indicating that these genes and proteins may be perturbed by both conditions.

Evaluation of phytotoxicity effect of olive mill wastewater treated by different technologies on seed germination of barley (Hordeum vulgare L.).

PubMed

Rusan, Munir J M; Albalasmeh, Ammar A; Zuraiqi, Said; Bashabsheh, Mohammad

2015-06-01

Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and plant growth. The objective of this study was to evaluate the impact of untreated and treated OMW with different techniques on seed germination of barley (Hordeum vulgare L.). The following treatments were investigated: (1) tap water (control); (2) OMW treated by aerobic biological technology in a Jacto Reactor (JR); (3) OMW treated by solar fenton oxidation (SFO); (4) OMW treated by microfiltration followed by nanofiltration (MF+NF); (5) OMW treated by microfiltration followed by reverse osmosis (MF+RO) process; (6) diluted OMW with tap water (25 % OMW); (7) diluted OMW with tap water (50 % OMW); (8) diluted OMW with tap water (75 % OMW); and (9) untreated OMW (100 % OMW). A germination test was conducted in an incubator at temperature of 23 (∘)C. In each petri dish, a filter paper was mounted and ten seeds of barley were placed on the filter paper. Five milliliter of water were added to each petri dish. The seed germination was determined by counting the number of germinated seeds to calculate the percentage of germination (G %). Germination rate index (GRI), seed vigor index (SVI), and phytotoxicity index (PI) were also calculated. Then, the dry weights and lengths of the shoots and the roots of the germinated seeds were measured. The results show that 100, 75, and 50 %OMW were very phytotoxic and completely prohibited seed germination. However, phytotoxicity decreased significantly following treatments of OMW with all techniques investigated and by the 25 % OMW dilution, as results of removing the phenols and other phytotoxic organic compounds from the OMW or by diluting it. This was evidenced by relative enhancement of the dry weights and lengths of shoot and root as well as the G %, GRI, SVG, and PI. It was concluded that if OMW will be used for irrigating crops, it has to be first treated or diluted with tap water at a ratio of 1:3 OMW:water at least. The most efficient treatment techniques in reducing the phytotoxicity of OMW were the MF+RO, followed by SFO and JR.

Feasibility of hydrogel fiducial markers for in vivo proton range verification using PET

NASA Astrophysics Data System (ADS)

Cho, Jongmin; Campbell, Patrick; Wang, Min; Alqathami, Mamdooh; Mawlawi, Osama; Kerr, Matthew; Cho, Sang Hyun

2016-03-01

Biocompatible/biodegradable hydrogel polymers were immersed in 18O-enriched water and 16O-water to create 18O-water hydrogels and 16O-water hydrogels. In both cases, the hydrogels were made of ~91 wt% water and ~9 wt% polymer. In addition, 5-8 μm Zn powder was suspended in 16O-water and 18O-enriched water and cross-linked with hydrogel polymers to create Zn/16O-water hydrogels (30/70 wt%, ~9 wt% polymer) and Zn/18O-water hydrogels (10/90 wt%), respectively. A block of extra-firm ‘wet’ tofu (12.3  ×  8.8  ×  4.9 cm, ρ  ≈  1.05 g cm-3) immersed in water was injected with Zn/16O-water hydrogels (0.9 ml each) at four different depths using an 18-gauge needle. Similarly, Zn/18O-water hydrogels (0.9 ml) were injected into a second tofu phantom. As a reference, both 16O-water hydrogels (1.8 ml) and 18O-water hydrogels (0.9 ml) in Petri dishes were irradiated in a ‘dry’ environment. The hydrogels in the wet tofu phantoms and dry Petri dishes were scanned via CT and images were used for treatment planning. Then, they were positioned at the proton distal dose fall-off region and irradiated (2 Gy) followed by PET/CT imaging. Notably high PET signals were observed only in 18O-water hydrogels in the dry environment. The visibility of the Zn/16O-water hydrogels injected into the tofu phantom was outstanding in CT images, but these hydrogels provided no noticeable PET signals. The visibility of the Zn/18O-water hydrogels in the wet tofu were excellent on CT and moderate on PET; however, the PET signals were weaker than those in the dry environment, possibly owing to 18O-water leaching out. The hydrogel markers studied here could be used to develop universal PET/CT fiducial markers. Their PET visibility (attributed more to activated 18O-water than Zn) after proton irradiation can be used for proton therapy/range verification. More investigation is needed to slow down the leaching of 18O-water.

A functionalized poly(ethylene glycol)-based bioassay surface chemistry that facilitates bio-immobilization and inhibits non-specific protein, bacterial, and mammalian cell adhesion

PubMed Central

Harbers, Gregory M.; Emoto, Kazunori; Greef, Charles; Metzger, Steven W.; Woodward, Heather N.; Mascali, James J.; Grainger, David W.; Lochhead, Michael J.

2008-01-01

This paper describes a new bioassay surface chemistry that effectively inhibits non-specific biomolecular and cell binding interactions, while providing a capacity for specific immobilization of desired biomolecules. Poly(ethylene glycol) (PEG) as the primary component in nonfouling film chemistry is well-established, but the multicomponent formulation described here is unique in that it (1) is applied in a single, reproducible, solution-based coating step; (2) can be applied to diverse substrate materials without the use of special primers; and (3) is readily functionalized to provide specific attachment chemistries. Surface analysis data are presented, detailing surface roughness, polymer film thickness, and film chemistry. Protein non-specific binding assays demonstrate significant inhibition of serum, fibrinogen, and lysozyme adsorption to coated glass, indium tin oxide, and tissue culture polystyrene dishes. Inhibition of S. aureus and K. pneumoniae microbial adhesion in a microfluidic flow cell, and inhibition of fibroblast cell adhesion from serum-based cell culture is shown. Effective functionalization of the coating is demonstrated by directing fibroblast adhesion to polymer surfaces activated with an RGD peptide. Batch-to-batch reproducibility data are included. The in situ cross-linked PEG-based coating chemistry is unique in its formulation, and its surface properties are attractive for a broad range of in vitro bioassay applications. PMID:18815622

Allelopathic effect of Bromus spp. and Lolium spp. shoot extracts on some crops.

PubMed

Lehoczky, E; Nelima, M Okumu; Szabó, R; Szalai, A; Nagy, P

2011-01-01

Allelopathy is an untapped resource for weed control in crops that could give good possibilities for environmentally sound, integrated crop production. Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the production of chemical compounds, called allelochemicals, which escape into the environment. Allelochemicals can be produced by weeds and affect crops, and the reverse is also true. Allelopathic interactions include weed-weed, weed-crop, and crop-crop. Allelopathy offers potential for selective biological weed control for instance weed-suppressing crops and the use of plant residues in cropping systems, allelopathic rotational crops, or companion plants with allelopathic potential. Bromus species occur in many habitats in temperate regions of the world, including America, Eurasia, Australia, and Africa. The genus Lolium is one of the most important forage grasses. The weed species usually grow in the same production zones as wheat and are considered weeds since they parasitize wheat fields. Some of the weed species in these two genus have been reported to have allelopathic effect. One of the methods that has been successful in studying allelopathic activity are bioassays. Laboratory experiments were conducted to determine allelopathic effect of watery shoot extracts of four weed species of the Poaceae family, namely Bromus rigidus, Bromus diandrus, Lolium multiflorum and Lolium temulentum on germination and growth of winter wheat (Triticum aestivum L.), spring barley (Hordeum vulgare L.), corn (Zea mays L), perennial ryegrass (Lolium perenne L.), bean (Phaseolus sp.) and sunflower (Helianthus annuus L.) and on each other. The experiment was carried out during the period March 2010 to October 2010. Twenty five seeds were put into one Petri-dish on filter paper, adding 15ml of extract to each in four repeats. The germination took place in a Binder-type thermostat in the dark. The timing of germination was checked in every two days and the rate of growth was estimated after a week, by counting the number of germinated seeds and measuring the length of the radicle and plumule. The measured data was statistically analyzed and the effect of the extracts on germination percentage and seedling length was evaluated.

Pristine Samples of Silicon Carbide Separated From the Canyon Diablo Meteorite

NASA Astrophysics Data System (ADS)

Leung, I. S.; Winston, R.

2008-12-01

The Canyon Diablo is an iron meteorite whose collision with Earth created Meteor Crater in Arizona. In a study of a large block (53 kg) of this meteorite, Henri Moissan reported his findings of green, hexagonal crystals of silicon carbide (SiC) which was given the name moissanite the following year by George Kunz (1905). Moissan did not report finding the cubic form of SiC. Subsequently, many erroneous reports appeared when the polishing compound (synthetic SiC) was mistakenly considered by researchers as a natural mineral associated with, rather than a contaminant of many rock types. Hence, the occurrence of SiC in the Canyon Diablo remains in doubt, and any proposal to investigate this problem was discouraged and regarded as predictably unproductive. This notion hampered further work on abundant materials housed in museums. SiC grains have been found in primitive meteorites and interplanetary dust particles. Some have been identified as presolar grains. The significance of SiC in the Canyon Diablo cannot be revealed unless we have abundant data from pristine samples, enough for us to classify them into presolar or other types. We report here a simple method we used to separate SiC crystals from the meteorite. We chose samples containing a carbon nodule composed of graphite, diamond-lonsdaleite, and SiC grains in the iron matrix. We broke up the carbon nodule with a sharp tungsten carbide chisel and hammer. After removing the large metal fragments, we put a small amount of the fine black grains in a Petri dish with acetone, then swerved the dish to scatter the grains sparingly on the bottom of the dish. Under a binocular microscope, SiC crystals can be spotted easily by their adamantine luster, color (blue, green, beige, etc.), and high birefringence when placed between crossed polarizers of a petrographic microscope. We also X-rayed individual grains, and have identified several hexagonal polytype structures as well as the cubic form (3C polytype).

Growth in spaceflight hardware results in alterations to the transcriptome and proteome.

PubMed

Basu, Proma; Kruse, Colin P S; Luesse, Darron R; Wyatt, Sarah E

2017-11-01

The Biological Research in Canisters (BRIC) hardware has been used to house many biology experiments on both the Space Transport System (STS, commonly known as the space shuttle) and the International Space Station (ISS). However, microscopic examination of Arabidopsis seedlings by Johnson et al. (2015) indicated the hardware itself may affect cell morphology. The experiment herein was designed to assess the effects of the BRIC-Petri Dish Fixation Units (BRIC-PDFU) hardware on the transcriptome and proteome of Arabidopsis seedlings. To our knowledge, this is the first transcriptomic and proteomic comparison of Arabidopsis seedlings grown with and without hardware. Arabidopsis thaliana wild-type Columbia (Col-0) seeds were sterilized and bulk plated on forty-four 60 mm Petri plates, of which 22 were integrated into the BRIC-PDFU hardware and 22 were maintained in closed containers at Ohio University. Seedlings were grown for approximately 3 days, fixed with RNAlater ® and stored at -80 °C prior to RNA and protein extraction, with proteins separated into membrane and soluble fractions prior to analysis. The RNAseq analysis identified 1651 differentially expressed genes; MS/MS analysis identified 598 soluble and 589 membrane proteins differentially abundant both at p < .05. Fold enrichment analysis of gene ontology terms related to differentially expressed transcripts and proteins highlighted a variety of stress responses. Some of these genes and proteins have been previously identified in spaceflight experiments, indicating that these genes and proteins may be perturbed by both conditions. Copyright © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

PetriScape - A plugin for discrete Petri net simulations in Cytoscape.

PubMed

Almeida, Diogo; Azevedo, Vasco; Silva, Artur; Baumbach, Jan

2016-06-04

Systems biology plays a central role for biological network analysis in the post-genomic era. Cytoscape is the standard bioinformatics tool offering the community an extensible platform for computational analysis of the emerging cellular network together with experimental omics data sets. However, only few apps/plugins/tools are available for simulating network dynamics in Cytoscape 3. Many approaches of varying complexity exist but none of them have been integrated into Cytoscape as app/plugin yet. Here, we introduce PetriScape, the first Petri net simulator for Cytoscape. Although discrete Petri nets are quite simplistic models, they are capable of modeling global network properties and simulating their behaviour. In addition, they are easily understood and well visualizable. PetriScape comes with the following main functionalities: (1) import of biological networks in SBML format, (2) conversion into a Petri net, (3) visualization as Petri net, and (4) simulation and visualization of the token flow in Cytoscape. PetriScape is the first Cytoscape plugin for Petri nets. It allows a straightforward Petri net model creation, simulation and visualization with Cytoscape, providing clues about the activity of key components in biological networks.

PetriScape - A plugin for discrete Petri net simulations in Cytoscape.

PubMed

Almeida, Diogo; Azevedo, Vasco; Silva, Artur; Baumbach, Jan

2016-03-01

Systems biology plays a central role for biological network analysis in the post-genomic era. Cytoscape is the standard bioinformatics tool offering the community an extensible platform for computational analysis of the emerging cellular network together with experimental omics data sets. However, only few apps/plugins/tools are available for simulating network dynamics in Cytoscape 3. Many approaches of varying complexity exist but none of them have been integrated into Cytoscape as app/plugin yet. Here, we introduce PetriScape, the first Petri net simulator for Cytoscape. Although discrete Petri nets are quite simplistic models, they are capable of modeling global network properties and simulating their behaviour. In addition, they are easily understood and well visualizable. PetriScape comes with the following main functionalities: (1) import of biological networks in SBML format, (2) conversion into a Petri net, (3) visualization as Petri net, and (4) simulation and visualization of the token flow in Cytoscape. PetriScape is the first Cytoscape plugin for Petri nets. It allows a straightforward Petri net model creation, simulation and visualization with Cytoscape, providing clues about the activity of key components in biological networks.

Preventing bacterial growth on implanted device with an interfacial metallic film and penetrating X-rays.

PubMed

An, Jincui; Sun, An; Qiao, Yong; Zhang, Peipei; Su, Ming

2015-02-01

Device-related infections have been a big problem for a long time. This paper describes a new method to inhibit bacterial growth on implanted device with tissue-penetrating X-ray radiation, where a thin metallic film deposited on the device is used as a radio-sensitizing film for bacterial inhibition. At a given dose of X-ray, the bacterial viability decreases as the thickness of metal film (bismuth) increases. The bacterial viability decreases with X-ray dose increases. At X-ray dose of 2.5 Gy, 98% of bacteria on 10 nm thick bismuth film are killed; while it is only 25% of bacteria are killed on the bare petri dish. The same dose of X-ray kills 8% fibroblast cells that are within a short distance from bismuth film (4 mm). These results suggest that penetrating X-rays can kill bacteria on bismuth thin film deposited on surface of implant device efficiently.

Electromagnetic field pretreatment of Sinapis alba seeds improved cadmium phytoextraction.

PubMed

Bulak, Piotr; Lata, Lesia; Plak, Andrzej; Wiącek, Dariusz; Strobel, Wacław; Walkiewicz, Anna; Pietruszewski, Stanisław; Bieganowski, Andrzej

2018-03-21

It was hypothesized that electromagnetic field (EMF) pretreatment of white mustard (Sinapis alba L.) seeds could increase the accumulation of non-essential, pollutant heavy metals such as cadmium (Cd) in shoots. Seeds of white mustard were treated with either 60 or 120 mT of alternating EMF (50 Hz) for 1 minute and then grown in a Petri dish in the presence of Cd, in comparison to the control (seeds grown without EMF pretreatment). Biomass production and content of calcium (Ca) and Cd in seedling shoots were measured. The Cd content in shoots from the EMF-treated seeds was higher in both variants than in the control (by 73% and 78%, respectively; p < 0.05). In plants treated with 60 mT, the Ca content was slightly, but significantly, lower (3%) than in the control. EMF stimulation did not affect the biomass production. The results have shown potential benefits of this physical seed pretreatment method in the context of cadmium phytoextraction, but more research is needed.

Height-resolved large-sample INAA of a 1 m long, 13 cm diameter ditch-bottom sample

NASA Astrophysics Data System (ADS)

Blaauw, M.; Baas, H. W.; Donze, M.

2003-06-01

A facility for instrumental neutron activation analysis (INAA) of large samples (up to 1 m long and 15 cm diameter) has been built. Correction methods for the simultaneous occurrence of neutron self-shielding and gamma-ray self-attenuation effects have been implemented and tested with a variety of samples. Now, the method has been extended to allow for the interpretation of scanned, collimated measurements, where results are obtained for individual voxels. As a validation and demonstration, a ditch-bottom sample of the maximum size was taken in a frozen condition. It was cut in 2 cm slices, still frozen, and put together again with each slice in a 2 cm height Petri dish divided in three sections. This allowed for verification of the results by ordinary INAA. Possible explanations for the discrepancies we observed between ordinary and large-sample INAA in the region where the concentration gradients are the steepest are discussed.

Dentifrice Containing Extract of Rosmarinus officinalis Linn.: An Antimicrobial Evaluation.

PubMed

Valones, Marcela Agne Alves; Higino, Jane Sheila; Souza, Paulo Roberto Eleutério; Crovella, Sérgio; Caldas, Arnaldo de França; Carvalho, Alessandra de Albuquerque Tavares

2016-01-01

This study aimed to evaluate the antimicrobial activity of a dentifrice containing an alcoholic extract of rosemary on oral bacteria, compared to a commercially available herbal dentifrice. Standard strains of Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 9811) and Lactobacillus rhamnosus (ATCC 7469) were used, as well as different toothpastes based on rosemary (TR), on propolis (TH), triclosan (positive control) (TPC) and non-fluoridated dentifrice (negative control) (TNC). Bacteria were seeded in Petri dishes and paper discs soaked with dilutions of dentifrice placed on the plates. The inhibition halos were analyzed. It was observed that TR did not show statistical difference in relation to the TH to inhibit S. mutans and S. oralis, while TH was more active against L. rhamnosus. The toothpaste containing rosemary extract had the ability to inhibit the growth of S. mutans, S. oralis and L. rhamnosus, revealing an antimicrobial activity similar to commercially available toothpastes for inhibition of S. mutans and S. oralis.

Isolation of Precursor Cells from Waste Solid Fat Tissue

NASA Technical Reports Server (NTRS)

Byerly, Diane; Sognier, Marguerite A.

2009-01-01

A process for isolating tissue-specific progenitor cells exploits solid fat tissue obtained as waste from such elective surgical procedures as abdominoplasties (tummy tucks) and breast reductions. Until now, a painful and risky process of aspiration of bone marrow has been used to obtain a limited number of tissue- specific progenitor cells. The present process yields more tissue-specific progenitor cells and involves much less pain and risk for the patient. This process includes separation of fat from skin, mincing of the fat into small pieces, and forcing a fat saline mixture through a sieve. The mixture is then digested with collagenase type I in an incubator. After centrifugation tissue-specific progenitor cells are recovered and placed in a tissue-culture medium in flasks or Petri dishes. The tissue-specific progenitor cells can be used for such purposes as (1) generating three-dimensional tissue equivalent models for studying bone loss and muscle atrophy (among other deficiencies) and, ultimately, (2) generating replacements for tissues lost by the fat donor because of injury or disease.

[Study on germination characteristics of Disporum cantoniense].

PubMed

Huang, Nan; Wang, Hua-Lei; Zhao, Zhi; Liu, Hong-Chang; Luo, Chun-Li; Li, Jin-Ling; Luo, Fu-Lai; Huang, Ming-Jin

2012-11-01

To study the seed germination characteristic and optimal germination condition of wild Disporum cantoniense. Used wild Disporum cantoniense seed as the test materials, the rate of water absorption of the seed was determined. The germination rates under different conditions, along a temperature gradient (15, 20, 25 and 30 degres C), in light or dark, on top or between wet filter papers, and keeping or removing the seed coat, were determined respectively using petri dish method. At the same time germination trends were observed. The thousand seed weight was 33.24 g, and the seed water-absorbing reached saturation pot after soaking for 30 h. Higher germination rates were respectively recorded at 25 degrees C, between filter papers, and in dark after 24 h soaking in the pretreatment solution. The optimal condition for the germination of the seed of wild Disporum cantoniense is as follow: keeping testa, seed soaking for 24 h in seed germination agent and being incubated between wet filter papers in dark at 25 degrees C.

Fluid Surface Deformation by Objects in the Cheerios Effect

NASA Astrophysics Data System (ADS)

Nguyen, Khoi; Miller, Michael; Mandre, Shreyas; Mandre Lab Team

2012-11-01

Small objects floating on a fluid/air interface deform of the surface depending on material surface properties, density, and geometry. These objects attract each other through capillary interactions, a phenomenon dubbed the ``cheerios effect.'' The attractive force and torque exerted on these objects by the interface can be estimated if the meniscus deformation is known. In addition, the floating objects can also rotate due to such an interaction. We present a series of experiments focused on visualizing the the motions of the floating objects and the deformation of the interface. The experiments involve thin laser-cut acrylic pieces attracting each other on water in a large glass petri dish and a camera set-up to capture the process. Furthermore, optical distortion of a grid pattern is used to visualize the water surface deformation near the edge of the objects. This study of the deformation of the water surface around a floating object, of the attractive/repulsive forces, and of post-contact rotational dynamics are potentially instrumental in the study of colloidal self-assembly.

A Filmy Black-Phosphorus Polyimide Saturable Absorber for Q-Switched Operation in an Erbium-Doped Fiber Laser.

PubMed

Feng, Tianxian; Mao, Dong; Cui, Xiaoqi; Li, Mingkun; Song, Kun; Jiang, Biqiang; Lu, Hua; Quan, Wangmin

2016-11-11

We demonstrate an erbium-doped fiber laser passively Q-switched by a black-phosphorus polyimide film. The multi-layer black-phosphorus (BP) nanosheets were prepared via a liquid exfoliation approach exploiting N -methylpyrrolidone as the dispersion liquid. By mixing the BP nanosheets with polyimide (PI), a piece of BP-PI film was obtained after evaporating the mixture in a petri dish. The BP-PI saturable absorber had a modulation depth of 0.47% and was inserted into an erbium-doped fiber laser to realize passive Q-switched operations. The repetition rate of the Q-switched laser increased from 5.73 kHz to 31.07 kHz when the laser pump was enhanced from 31.78 mW to 231.46 mW. Our results show that PI is an excellent host material to protect BP from oxidation, and the BP-PI film can act as a promising nonlinear optical device for laser applications.

Cleaning Puparia for Forensic Analysis.

PubMed

Higley, Leon G; Brosius, Tierney R; Reinhard, Karl J; Carter, David

2016-09-01

We tested procedures for removing adipocere from insect samples to allow identification. An acceptable procedure was determined: (i) Samples were sorted in petri dishes with 75% alcohol to remove any larvae, adult insects, or other soft-bodied material. (ii) Samples of up to 24 puparia were placed in a vial with 15 mL of 95% acetone, capped, and vortexed for a total of 30-90 sec in 10- to 15-sec bursts. This step removed large masses of adipocere or soil from specimen. (iii) Specimens were removed from acetone and placed in a vial of 15 mL of 2% potassium hydroxide (KOH) and vortexed in 10- to 15-sec bursts until all puparia appeared clean (with our samples this required a total of 60-120 sec). (iv) Specimens were removed from the 2% KOH, placed in 75% ethanol, and examined microscopically. (v) Material was stored in 75% ethanol for identification and long-term preservation. © 2016 American Academy of Forensic Sciences.

Antifungal effect of gaseous nitric oxide on mycelium growth, sporulation and spore germination of the postharvest horticulture pathogens, Aspergillus niger, Monilinia fructicola and Penicillium italicum.

PubMed

Lazar, E E; Wills, R B H; Ho, B T; Harris, A M; Spohr, L J

2008-06-01

To evaluate the antifungal activity of nitric oxide (NO) against the growth of the postharvest horticulture pathogens Aspergillus niger, Monilinia fructicola and Penicillium italicum under in vitro conditions. Different volumes of NO gas were injected into the Petri dish headspace to obtain the desired concentrations of 50-500 microl l(-1). The growth of the fungi was measured for 8 days of incubation in air at 25 degrees C. All concentrations of NO were found to produce an antifungal effect on spore germination, sporulation and mycelial growth of the three fungi, with the most effective concentration for A. niger and P. italicum being 100 and 500 microl l(-1) for M. fructicola. Short-term exposure to a low concentration of NO gas was able to inhibit the subsequent growth of A. niger, M. fructicola and P. italicum. NO gas has potential use as a natural fungicide to inhibit microbial growth on postharvest fruit and vegetables.

Relative differences in susceptibility of Pieris taxa (Ericaceae) to Stephanitis spp. lace bugs (Hemiptera: Tingidae).

PubMed

Nair, Shakunthala; Braman, S Kristine; Knauft, D A

2012-10-01

Over 60 Pieris taxa (Ericaceae) were measured for their susceptibility to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, and the azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae) based on leaf damage, adult survival on leaves, and emergence of nymphs in no-choice petri dish assays. Pieris phillyreifolia (Hook.) DC. and P. japonica (Thunb.) D.Don ex G.Don 'Variegata' were consistently resistant to both species of lace bugs, whereas P. japonica 'Cavatine' was consistently susceptible to both. Pieris japonica 'Temple Bells' was highly susceptible to S. takeyai, but resistant to S. pyrioides. Nymph emergence was noted only with S. takeyai, on 46 Pieris taxa, whereas S. pyrioides nymphs were not observed on any of the Pieris taxa. Choice assays (with 10 Pieris taxa) and whole plant assays (with five Pieris taxa) using S. takeyai alone also were conducted, confirming the resistance of P. phillyreifolia and susceptibility of P. japonica Temple Bells to lace bug feeding.

Expansion of Human Mesenchymal Stem Cells in a Microcarrier Bioreactor.

PubMed

Tsai, Ang-Chen; Ma, Teng

2016-01-01

Human mesenchymal stem cells (hMSCs) are considered as a primary candidate in cell therapy owing to their self-renewability, high differentiation capabilities, and secretions of trophic factors. In clinical application, a large quantity of therapeutically competent hMSCs is required that cannot be produced in conventional petri dish culture. Bioreactors are scalable and have the capacity to meet the production demand. Microcarrier suspension culture in stirred-tank bioreactors is the most widely used method to expand anchorage dependent cells in a large scale. Stirred-tank bioreactors have the potential to scale up and microcarriers provide the high surface-volume ratio. As a result, a spinner flask bioreactor with microcarriers has been commonly used in large scale expansion of adherent cells. This chapter describes a detailed culture protocol for hMSC expansion in a 125 mL spinner flask using microcarriers, Cytodex I, and a procedure for cell seeding, expansion, metabolic sampling, and quantification and visualization using microculture tetrazolium (MTT) reagent.

Sombrero-shaped plasmonic nanoparticles with molecular-level sensitivity and multifunctionality.

PubMed

Wi, Jung-Sub; Barnard, Edward S; Wilson, Robert J; Zhang, Mingliang; Tang, Mary; Brongersma, Mark L; Wang, Shan X

2011-08-23

We demonstrate top-down synthesis of monodisperse plasmonic nanoparticles designed to contain internal Raman hot spots. Our Raman-active nanoparticles are fabricated using nanoimprint lithography and thin-film deposition and are composed of novel internal structures with sublithographic dimensions: a disk-shaped Ag core, a Petri-dish-shaped SiO(2) base whose inner surface is coated with Ag film, and a sub-10 nm scale circular gap between the core and the base. Confocal Raman measurements and electromagnetic simulations show that Raman hot spots appear at the inside perimeter of individual nanoparticles and serve as the source of a 1000-fold improvement of minimum molecular detection level that enables detection of signals from a few molecules near hot spots. A multimodality version of these nanoparticles, which includes the functionality offered by magnetic multilayers, is also demonstrated. These results illustrate the potential of direct fabrication for creating exotic monodisperse nanoparticles, which combine engineered internal nanostructures and multilayer composite materials, for use in nanoparticle-based molecular imaging and detection. © 2011 American Chemical Society

Multi-agent Simulations of Population Behavior: A Promising Tool for Systems Biology.

PubMed

Colosimo, Alfredo

2018-01-01

This contribution reports on the simulation of some dynamical events observed in the collective behavior of different kinds of populations, ranging from shape-changing cells in a Petri dish to functionally correlated brain areas in vivo. The unifying methodological approach, based upon a Multi-Agent Simulation (MAS) paradigm as incorporated in the NetLogo™ interpreter, is a direct consequence of the cornerstone that simple, individual actions within a population of interacting agents often give rise to complex, collective behavior.The discussion will mainly focus on the emergence and spreading of synchronous activities within the population, as well as on the modulation of the collective behavior exerted by environmental force-fields. A relevant section of this contribution is dedicated to the extension of the MAS paradigm to Brain Network models. In such a general framework some recent applications taken from the direct experience of the author, and exploring the activation patterns characteristic of specific brain functional states, are described, and their impact on the Systems-Biology universe underlined.

Effects of Some Pesticides on the Growth of ARF18 and Its Pathogenicity to Heterodera glycines

PubMed Central

Kim, D. G.; Riggs, R. D.

1998-01-01

The effects of 22 pesticides on the mycelial growth and pathogenicity of the biocontrol fungus ARFI8 to Heterodera glycines were tested in vitro. The chemicals were added to agar at 10, 100, and 1,000 ppm a.i.; a block of agar containing the fungus was added to each test concentration; and fungal growth was measured. Subsequently, a block of the fungus on the pesticide-containing agar was used to determine the ability of the fungus to parasitize eggs of H. glycines. Aldicarb, bentazone, and chlorothalonil had little or no effect on fungal growth, whereas benomyl and thiophanate methyl completely inhibited growth of the fungus at 10 ppm. The relative insensitivity of ARF18 to certain pesticides would permit selected use of those pesticides with ARF18 in an integrated control program if the effects on the fungus in the field are similar to results from petri dish studies. PMID:19274211

Impeding movement of the poultry red mite, Dermanyssus gallinae.

PubMed

Pritchard, James; Küster, Tatiana; George, David; Sparagano, Olivier; Tomley, Fiona

2016-07-30

The poultry red mite, Dermanyssus gallinae, is an economically important hematophagous parasite of commercial egg laying hens, also affecting domesticated birds and companion animals. Conventional control of D. gallinae through acaricidal spraying is often ineffective, creating an urgent need to identify alternative management strategies for commercial and domestic infestations. Whilst integrated pest management is being considered for D. gallinae, the potential of impeding mite 'migration' routes, to either prevent initial infestation or manage established populations, has not been researched. Here we demonstrate that barriers of insecticidal glue, double sided sticky tape and thyme oil can contain D. gallinae within a specified area of a petri dish (78-88% of total mite population) and this level of containment was significantly greater than for negative controls (p values <0.05). Further studies in poultry houses are recommended to investigate the efficacy of these barriers in real world application and identity potential for barriers as a strategy for mite control. Copyright © 2016 Elsevier B.V. All rights reserved.

Ammonia Volatilization from Urea-Application Influenced Germination and Early Seedling Growth of Dry Direct-Seeded Rice

PubMed Central

Qi, Xiaoli; Wu, Wei; Shah, Farooq; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Liu, Hongyan; Nie, Lixiao

2012-01-01

Poor seed germination and early seedling growth associated with urea-induced soil ammonia volatilization are major constraints in the adoption of dry direct-seeded rice. To directly examine soil ammonia volatilization and its damage to seed germination and early seedling growth of dry direct-seeded rice when urea is applied at seeding, two Petri-dish incubation experiments and a field experiment were conducted. Ammonia volatilization due to urea application significantly reduced seed germination and early seedling growth of dry direct-seedling rice. NBPT significantly reduced ammonia volatilization following urea application. The application of ammonium sulfate, instead of urea at seeding, may mitigate poor crop establishment of dry direct-seeded rice. Root growth of dry direct-seeded rice was more seriously inhibited by soil ammonia volatilization than that of shoot. Results suggest that roots are more sensitive to soil ammonia toxicity than shoots in dry direct-seeded rice system when N is applied as urea at seeding. PMID:22454611

Development of antimicrobial active packaging materials based on gluten proteins.

PubMed

Gómez-Heincke, Diana; Martínez, Inmaculada; Partal, Pedro; Guerrero, Antonio; Gallegos, Críspulo

2016-08-01

The incorporation of natural biocide agents into protein-based bioplastics, a source of biodegradable polymeric materials, manufactured by a thermo-mechanical method is a way to contribute to a sustainable food packaging industry. This study assesses the antimicrobial activity of 10 different biocides incorporated into wheat gluten-based bioplastics. The effect that formulation, processing, and further thermal treatments exert on the thermo-mechanical properties, water absorption characteristics and rheological behaviour of these materials is also studied. Bioplastics containing six of the 10 examined bioactive agents have demonstrated suitable antimicrobial activity at 37 °C after their incorporation into the bioplastic. Moreover, the essential oils are able to create an antimicrobial atmosphere within a Petri dish. Depending on the selected biocide, its addition may alter the bioplastics protein network in a different extent, which leads to materials exhibiting less water uptake and different rheological and thermo-mechanical behaviours. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

PubMed

Remmert, Hermann

1970-06-01

Limosina brachystoma can be reared even when the food and substratum (dry leaves of Urtica or almost any other plant) are moistened with 15‰ NaCl p.a. or with 15‰ NaCl plus KCl. Orchestia lives about three weeks if kept on a substratum moistened with a solution of 15‰ NaCl (Food: Fucus).H 2 SO 4 , on the other hand, is fatal especially, for Orchestia.Burning oil gives off pollutants into the surrounding water. These pollutants are fatal for all the animals studied even at very low concentrations. But in air (not in water) these pollutants disappear within one week and the substratum may be colonized again.Crude oil which has floated in the sea for a long time is not any longer poisonous to the animals studied. It does not hinder rapid propagation of all species Larvae of the flies and - to a lesser extent - of the amphipodes rummage in their substratum and disperse a big piece of old crude oil into fine parts throughout the petri dish.

Permethrin treated clothing to protect outdoor workers: evaluation of different methods for mosquito exposure against populations with differing resistance status.

PubMed

Richards, Stephanie L; Agada, Nwanne; Balanay, Jo Anne G; White, Avian V

2018-02-01

Minimizing arthropod exposure (e.g. mosquito and tick bites) is vital to protect health of outdoor workers. Personal protective measures can help protect against exposure. Here, the quantity of permethrin was evaluated for different fabric types after washing. Cone and petri dish exposure assays were used to investigate the knockdown/mortality of permethrin-susceptible and permethrin-resistant populations of mosquitoes. Permethrin-treated clothing was effective against the tested mosquito population that was susceptible to permethrin but not a permethrin-resistant population. Permethrin quantity was significantly highest in the 100% cotton fabric and for the 0 wash group. Permethrin quantity in fabrics decreased with washing. No significant differences (p > 0.05) were observed in knockdown/mortality rates for either exposure method. The protective effect of permethrin-treated clothing against mosquitoes is impacted by many factors, e.g. wash frequency, fabric type, and the susceptibility/resistance status of local mosquito populations.

Alterations in the Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene after Cultivation in the Human Spaceflight Environment.

PubMed

Fajardo-Cavazos, Patricia; Leehan, Joshua D; Nicholson, Wayne L

2018-01-01

The effect of Bacillus subtilis exposure to the human spaceflight environment on growth, mutagenic frequency, and spectrum of mutations to rifampicin resistance (Rif R ) was investigated. B. subtilis cells were cultivated in Biological Research in Canister-Petri Dish Fixation Units (BRIC-PDFUs) on two separate missions to the International Space Station (ISS), dubbed BRIC-18 and BRIC-21, with matching asynchronous ground controls. No statistically significant difference in either growth or in the frequency of mutation to Rif R was found in either experiment. However, nucleotide sequencing of the Rif R regions of the rpoB gene from Rif R mutants revealed dramatic differences in the spectrum of mutations between flight (FL) and ground control (GC) samples, including two newly discovered rpoB alleles in the FL samples (Q137R and L489S). The results strengthen the idea that exposure to the human spaceflight environment causes unique stresses on bacteria, leading to alterations in their mutagenic potential.

Examination of common ragweed's (Ambrosia artemisiifolia L.) allelopathic effect on some weed species.

PubMed

Lehoczky, E; Szabó, R; Nelima, M Okumu; Nagy, P; Béres, I

2010-01-01

In the last decades the importance of some weed species increased in Hungary. The common ragweed (Ambrosia artemisiifolia L.) also belongs to this group. The allelopathic effect of watery extract made from different plant parts of common ragweed (air dried leafy shoots, seeds) were studied on the germination and growth of some weed species. The extracts were prepared with tap water, chopped dry plant materials were added to water and 24 hours later the material was filtered. The germination took place in a Binder KBW type thermostat in dark. 25 seeds were put into one Petri-dish, adding 15 ml plant extract to each in four repeats. The timing of germination was checked in every two days and the rate of growth was estimated after a week, by counting the numbers of germinated seeds and measuring the length of the radicle and plumula. The measured data were statistically analysed and the effect of extracts on germinating ratio and seedling length were evaluated.

Wheat and ultra high diluted gibberellic acid--further experiments and re-analysis of data.

PubMed

Endler, Peter Christian; Scherer-Pongratz, Waltraud; Lothaller, Harald; Stephen, Saundra

2015-10-01

Following studies (a) on wheat seedlings and ultra high diluted silver nitrate, and (b) on amphibians and an ultra high diluted hormone, (c) a bio-assay on wheat and extremely diluted gibberellic acid was standardized. This assay was intended to combine the easy-to-handle aspect of (a) and biologically interesting aspects of (b). The purpose of the data analysis presented here was to investigate the influence of an extreme dilution of gibberellic acid on wheat stalk length and to determine the influence of external factors on the experimental outcome. Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10(-30)) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy ('G30x'). Analogously prepared water was used for control ('W30x'). 16 experiments including 8000+8000 grains were performed by 9 researchers. Experiments that were performed between January and April showed inconsistent results, whereas most of the experiments performed between September and December showed shorter stalks in the G30x group. This was confirmed by correlation analysis (p<0.01). Thus winter/spring experiments and autumn experiments were analysed separately. When all 10 autumn experiments were pooled, mean stalk lengths (mm) were 48.3±21.4 for the verum group and 52.1±20.4 for control (mean±SD) at grain level (N=5000 per group) and ±5.3 and ±5.1 respectively at dish level. In other words, verum stalk length (92.67%) was 7.33% smaller than control stalk length (100%). The effect size is small when calculation is done on the basis of grains (d=0.18) but, due to the smaller SD at dish level, medium when done on the basis of dishes (d=0.73). The inhibiting effect was observed by 6 of the 6 researchers who performed the autumn experiments. The model may be useful for further research as there exists a theoretical justification due to previous studies with wheat and extremely diluted silver nitrate, as well as to previous studies with amphibians and diluted hormones, and its methods are well standardized. Data confirm the hypothesis that information can be stored in the test liquid, even at a dilution of the original substance beyond Avogadro's value; and that the wheat bio-assay is sensitive to such information. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

The Crystals Cave in a test tube

NASA Astrophysics Data System (ADS)

Puig, C.; Romero, M. L.

2012-04-01

It's quite easy to understand formation of crystals in Nature by evaporation of the solutions that contain minerals, but many times we have realised that our pupils hardly understand that precipitation is a process mostly caused by changing parameters in a solution, like pH, temperature, etc. and not necessarily depending on evaporation. We propose a hands-on activity using the context of the Cave of the Crystals in Naica's mine, Mexico. The Crystals Cave is a wonderful place where giant crystals of selenite (gypsum) have grown feeding from a supersaturated anhydrite solution1. Miners discovered the cave filled with hot water, and drained it to explore the gallery. The cave is now a giant laboratory where scientists are looking for the keys to understand geological processes. Teaching sequence (for students 15 years old) is as follows: DISCOVERING A MARVELLOUS PLACE: We showed our pupils several images and a short video of the Cave of the Crystals and ask them about the process that may have caused the phenomenon. Whole-class discussion. PRESENTING A CHALLENGE TO OUR STUDENTS: "COULD WE CREATE A CRYSTALS CAVE IN A TEST TUBE?" EXPERIMENTING TO IMITATE NATURE: Students tried to grow crystals simulating the same conditions as those in Naica's mine. We have chosen KNO3, a salt more soluble than gypsum. We added 85 g of salt to 200 ml of water (solubility of KNO3 at 25°C is 36 g per 100 gr of water) and heated it until it is dissolved. Afterwards, we poured the solution into some test tubes and other recipients and let them cool at room temperature. And they got a beautiful crystals cave!! THINKING A LITTLE MORE: we asked pupils some questions to make them think about the process and to predict what would happen in different situations. For example: a) What would happen with crystals if we heated the tubes again? or b) What would happen if we took the remaining solution from the tubes and keep it in the fridge? PROVING A NEW HYPOTHESIS: Pupils collected the remaining solutions from all the containers, poured them in a Petri dish and let them inside the fridge for a day: New crystals grew at the bottom of the Petri dishes!!! LOOKING FOR THE SCIENTIFIC EXPLANATIONS: We made them work in pairs in order to find an explanation about giant crystals in Naica's mine, by using short videos2, a scientific article or any information they can find on line. THINKING OF FUTURE: Should we close Naica's mine in order to preserve it? Whole-class discussion

DETERMINATION OF THE MAXIMUM INHIBITORY DILUTION OF CETYLPYRIDINIUM CHLORIDE-BASED MOUTHWASHES AGAINST STAPHYLOCOCCUS AUREUS: AN IN VITRO STUDY

PubMed Central

Watanabe, Evandro; Tanomaru, Juliane Maria Guerreiro; Nascimento, Andresa Piacezzi; Matoba, Fumio; Tanomaru, Mario; Ito, Izabel Yoko

2008-01-01

The aim of this in vitro study was to determine the maximum inhibitory dilution (MID) of four cetylpyridinium chloride (CPC)-based mouthwashes: CPC+Propolis, CPC+Malva, CPC+Eucaliptol+Juá+Romã+Propolis (Natural Honey®) and CPC (Cepacol®), against 28 Staphylococcus aureus field strains, using the agar dilution method. Decimal dilutions ranging from 1/10 to 1/ 655,360 were prepared and added to Mueller Hinton Agar. Strains were inoculated using Steers multipoint inoculator. The inocula were seeded onto the surface of the culture medium in Petri dishes containing different dilutions of the mouthwashes. The dishes were incubated at 37°C for 24 h. For readings, the MID was considered as the maximum dilution of mouthwash still capable of inhibiting microbial growth. The obtained data showed that CPC+Propolis had antimicrobial activity against 27 strains at 1/320 dilution and against all 28 strains at 1/160 dilution, CPC+Malva inhibited the growth of all 28 strains at 1/320 dilution, CPC+Eucaliptol+Juá+Romã+Propolis inhibited the growth of 2 strains at 1/640 dilution and all 28 strains at 1/320 dilution, and Cepacol® showed antimicrobial activity against 3 strains at 1/320 dilution and against all 28 strains at 1/160 dilution. Data were submitted to Kruskal-Wallis test, showing that the MID of Cepacol® was lower than that determined for the other products (p<0.05). In conclusion, CPC-mouthwashes showed antimicrobial activity against S. aureus and the addition of other substances to CPC improved its antimicrobial effect. PMID:19089260

In vitro comparison of four treatments which discourage infestation by head lice.

PubMed

Greive, Kerryn A; Barnes, Tanya M

2012-05-01

Products which discourage the transmission of head lice are appealing; however, few studies have tested this concept. This study aims to test the efficacy of four commercial products which claim to discourage infestation by head lice; MOOV Head Lice Defence Spray (MOOV), Wild Child Quit Nits Head Lice Defence Spray (Wild Child), 100% Natural Head Lice Beater (Lice Beater) or Lysout Natural Anti-Lice Spray (Lysout). An in vitro challenge test was used. Briefly, one half of a filter paper lining the base of a petri dish was treated with the test product. Lice were then introduced to the centre of the dish, which was covered and placed in the dark at 20°C for 30 min. The number of lice on the treated and untreated sides of the filter paper was then counted after 2, 4 and 8 h post-application. MOOV was significantly more effective at discouraging the transmission of lice than the water control (p < 0.01), while Wild Child and Lysout were not at all time points. Lice Beater was significantly worse than the water control after 2 h (p < 0.01), while there was no difference after 4 and 8 h. MOOV was found to perform significantly better than Wild Child (p < 0.05) and Lice Beater (p < 0.05) at all time points. It also performed significantly better than Lysout at 2 (p < 0.05) and 8 h (p < 0.05), but not 4 h. MOOV offers the best efficacy and consistency of performance of the four products tested to discourage the transmission of head lice.

Petri net controllers for distributed robotic systems

NASA Technical Reports Server (NTRS)

Lefebvre, D. R.; Saridis, George N.

1992-01-01

Petri nets are a well established modelling technique for analyzing parallel systems. When coupled with an event-driven operating system, Petri nets can provide an effective means for integrating and controlling the functions of distributed robotic applications. Recent work has shown that Petri net graphs can also serve as remarkably intuitive operator interfaces. In this paper, the advantages of using Petri nets as high-level controllers to coordinate robotic functions are outlined, the considerations for designing Petri net controllers are discussed, and simple Petri net structures for implementing an interface for operator supervision are presented. A detailed example is presented which illustrates these concepts for a sensor-based assembly application.

Characterization of ligninolytic enzyme production in white-rot wild fungal strains suitable for kraft pulp bleaching.

PubMed

Damián-Robles, Rosa María; Castro-Montoya, Agustín Jaime; Saucedo-Luna, Jaime; Vázquez-Garcidueñas, Ma Soledad; Arredondo-Santoyo, Marina; Vázquez-Marrufo, Gerardo

2017-10-01

Fungal strains identified by phylogenetic analysis of the ITS rDNA region as Trametes versicolor (CMU-TA01), Irpex lacteus (CMU-84/13), and Phlebiopsis sp. (CMU-47/13) are able to grow on and bleach kraft pulp (KP) in a simple solid-state fermentation (SSF) assay conducted in Petri dishes. Kappa number reductions obtained with Phlebiopsis sp. (48.3%), T. versicolor (43%), and I . lacteus (39.3%), evidence their capability for lignin breakdown. Scanning electron microscopy images of KP fibers from SSF assays demonstrated increased roughness and striation, evidencing significant cell wall modification. T. versicolor produces laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP) in potato dextrose broth (PDB), PDB + CuSO 4 , and PDB + KP, whereas Phlebiopsis sp. and I. lacteus showed no Lac and low LiP activities in all media. Compared to PDB, the highest increase in Lac (7.25-fold) and MnP (2.37-fold) activities in PDB + CuSO 4 occur in T. versicolor ; for LiP, the greatest changes (6.95-fold) were observed in I. lacteus . Incubation in PDB + KP shows significant increases in Lac and MnP for T. versicolor , MnP and LiP for Phlebiopsis sp., and none for I. lacteus . SSF assays in Petri plates are a valuable tool to select fungi that are able to delignify KP. Here, delignification by Phlebiopsis sp. of this substrate is reported for the first time, and MnP activity was strongly associated with the delignification ability of the studied strains. The obtained results suggest that the studied fungal strains have biotechnological potential for use in the paper industry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chew, K. W.; Chen, S. S.; Pang, W. L.

The effects of Lithium triflate salt (LiCF{sub 3}SO{sub 3}), on the poly (methyl methacrylate)(PMMA)-based solid polymer electrolytes plasticized with propylene carbonate (PC) solvated in Tetrahydrofuran (THF) have been studied through a.c impedance spectroscopy and infrared spectroscopy. Lithium triflate was incorporated into the predetermined PMMA/PC system that has the highest value of ionic conductivity. In current investigations, four combination systems: Pure PMMA, (PMMA+PC) systems, (PMMA+LiCF{sub 3}SO{sub 3}) and (PMMA+PC+LiCF{sub 3}SO{sub 3}) systems were prepared using the solution cast method. Solutions were stirred for numerous hours to obtain a homogenous solution before it is poured into the petri dishes under ambient temperaturemore » to form the solid electrolyte thin film. The films were then removed from petri discs and transferred into the dessicator for further drying prior to the different tests. From the characterization done through the a.c impedance spectroscopy, the highest room temperature ionic conductivity in the pure PMMA sample, (PMMA+PC) system and (PMMA+LiCF{sub 3}SO{sub 3}) system is 2.83x10{sup -12} Scm{sup -1}, 4.39x10{sup -11} Scm{sup -1} and 3.93x10{sup -6} Scm{sup -1} respectively. The conductivity for (PMMA+PC+LiCF{sub 3}SO{sub 3}) system was obtained with the 30 wt% of lithium triflate, which is 2.48x10{sup -5} Scm{sup -1}. Infrared spectroscopy shows that complexation occurred between the polymer and the plasticizer, and the polymer and plasticizer and salt. The interactions have been studied in the C=O band, C-O-C band and the O-CH{sub 3} band.« less

ARG1 Functions in the Physiological Adaptation of Undifferentiated Plant Cells to Spaceflight

NASA Astrophysics Data System (ADS)

Zupanska, Agata K.; Schultz, Eric R.; Yao, JiQiang; Sng, Natasha J.; Zhou, Mingqi; Callaham, Jordan B.; Ferl, Robert J.; Paul, Anna-Lisa

2017-11-01

Scientific access to spaceflight and especially the International Space Station has revealed that physiological adaptation to spaceflight is accompanied or enabled by changes in gene expression that significantly alter the transcriptome of cells in spaceflight. A wide range of experiments have shown that plant physiological adaptation to spaceflight involves gene expression changes that alter cell wall and other metabolisms. However, while transcriptome profiling aptly illuminates changes in gene expression that accompany spaceflight adaptation, mutation analysis is required to illuminate key elements required for that adaptation. Here we report how transcriptome profiling was used to gain insight into the spaceflight adaptation role of Altered response to gravity 1 (Arg1), a gene known to affect gravity responses in plants on Earth. The study compared expression profiles of cultured lines of Arabidopsis thaliana derived from wild-type (WT) cultivar Col-0 to profiles from a knock-out line deficient in the gene encoding ARG1 (ARG1 KO), both on the ground and in space. The cell lines were launched on SpaceX CRS-2 as part of the Cellular Expression Logic (CEL) experiment of the BRIC-17 spaceflight mission. The cultured cell lines were grown within 60 mm Petri plates in Petri Dish Fixation Units (PDFUs) that were housed within the Biological Research In Canisters (BRIC) hardware. Spaceflight samples were fixed on orbit. Differentially expressed genes were identified between the two environments (spaceflight and comparable ground controls) and the two genotypes (WT and ARG1 KO). Each genotype engaged unique genes during physiological adaptation to the spaceflight environment, with little overlap. Most of the genes altered in expression in spaceflight in WT cells were found to be Arg1-dependent, suggesting a major role for that gene in the physiological adaptation of undifferentiated cells to spaceflight.

Sociophysics of sexism: normal and anomalous petrie multipliers

NASA Astrophysics Data System (ADS)

Eliazar, Iddo

2015-07-01

A recent mathematical model by Karen Petrie explains how sexism towards women can arise in organizations where male and female are equally sexist. Indeed, the Petrie model predicts that such sexism will emerge whenever there is a male majority, and quantifies this majority bias by the ‘Petrie multiplier’: the square of the male/female ratio. In this paper—emulating the shift from ‘normal’ to ‘anomalous’ diffusion—we generalize the Petrie model to a stochastic Poisson model that accommodates heterogeneously sexist men and woman, and that extends the ‘normal’ quadratic Petrie multiplier to ‘anomalous’ non-quadratic multipliers. The Petrie multipliers span a full spectrum of behaviors which we classify into four universal types. A variation of the stochastic Poisson model and its Petrie multipliers is further applied to the context of cyber warfare.

A new variant of Petri net controlled grammars

NASA Astrophysics Data System (ADS)

Jan, Nurhidaya Mohamad; Turaev, Sherzod; Fong, Wan Heng; Sarmin, Nor Haniza

2015-10-01

A Petri net controlled grammar is a Petri net with respect to a context-free grammar where the successful derivations of the grammar can be simulated using the occurrence sequences of the net. In this paper, we introduce a new variant of Petri net controlled grammars, called a place-labeled Petri net controlled grammar, which is a context-free grammar equipped with a Petri net and a function which maps places of the net to productions of the grammar. The language consists of all terminal strings that can be obtained by parallelly applying multisets of the rules which are the images of the sets of the input places of transitions in a successful occurrence sequence of the Petri net. We study the effect of the different labeling strategies to the computational power and establish lower and upper bounds for the generative capacity of place-labeled Petri net controlled grammars.

Modeling of Biometric Identification System Using the Colored Petri Nets

NASA Astrophysics Data System (ADS)

Petrosyan, G. R.; Ter-Vardanyan, L. A.; Gaboutchian, A. V.

2015-05-01

In this paper we present a model of biometric identification system transformed into Petri Nets. Petri Nets, as a graphical and mathematical tool, provide a uniform environment for modelling, formal analysis, and design of discrete event systems. The main objective of this paper is to introduce the fundamental concepts of Petri Nets to the researchers and practitioners, both from identification systems, who are involved in the work in the areas of modelling and analysis of biometric identification types of systems, as well as those who may potentially be involved in these areas. In addition, the paper introduces high-level Petri Nets, as Colored Petri Nets (CPN). In this paper the model of Colored Petri Net describes the identification process much simpler.

Constructing biological pathway models with hybrid functional Petri nets.

PubMed

Doi, Atsushi; Fujita, Sachie; Matsuno, Hiroshi; Nagasaki, Masao; Miyano, Satoru

2004-01-01

In many research projects on modeling and analyzing biological pathways, the Petri net has been recognized as a promising method for representing biological pathways. From the pioneering works by Reddy et al., 1993, and Hofestädt, 1994, that model metabolic pathways by traditional Petri net, several enhanced Petri nets such as colored Petri net, stochastic Petri net, and hybrid Petri net have been used for modeling biological phenomena. Recently, Matsuno et al., 2003b, introduced the hybrid functional Petri net (HFPN) in order to give a more intuitive and natural modeling method for biological pathways than these existing Petri nets. Although the paper demonstrates the effectiveness of HFPN with two examples of gene regulation mechanism for circadian rhythms and apoptosis signaling pathway, there has been no detailed explanation about the method of HFPN construction for these examples. The purpose of this paper is to describe method to construct biological pathways with the HFPN step-by-step. The method is demonstrated by the well-known glycolytic pathway controlled by the lac operon gene regulatory mechanism.

Constructing biological pathway models with hybrid functional petri nets.

PubMed

Doi, Atsushi; Fujita, Sachie; Matsuno, Hiroshi; Nagasaki, Masao; Miyano, Satoru

2011-01-01

In many research projects on modeling and analyzing biological pathways, the Petri net has been recognized as a promising method for representing biological pathways. From the pioneering works by Reddy et al., 1993, and Hofestädt, 1994, that model metabolic pathways by traditional Petri net, several enhanced Petri nets such as colored Petri net, stochastic Petri net, and hybrid Petri net have been used for modeling biological phenomena. Recently, Matsuno et al., 2003b, introduced the hybrid functional Petri net (HFPN) in order to give a more intuitive and natural modeling method for biological pathways than these existing Petri nets. Although the paper demonstrates the effectiveness of HFPN with two examples of gene regulation mechanism for circadian rhythms and apoptosis signaling pathway, there has been no detailed explanation about the method of HFPN construction for these examples. The purpose of this paper is to describe method to construct biological pathways with the HFPN step-by-step. The method is demonstrated by the well-known glycolytic pathway controlled by the lac operon gene regulatory mechanism.

TokenPasser: A petri net specification tool. Thesis

NASA Technical Reports Server (NTRS)

Mittmann, Michael

1991-01-01

In computer program design it is essential to know the effectiveness of different design options in improving performance, and dependability. This paper provides a description of a CAD tool for distributed hierarchical Petri nets. After a brief review of Petri nets, Petri net languages, and Petri net transducers, and descriptions of several current Petri net tools, the specifications and design of the TokenPasser tool are presented. TokenPasser is a tool to allow design of distributed hierarchical systems based on Petri nets. A case study for an intelligent robotic system is conducted, a coordination structure with one dispatcher controlling three coordinators is built to model a proposed robotic assembly system. The system is implemented using TokenPasser, and the results are analyzed to allow judgment of the tool.

Utilization Elementary Siphons of Petri Net to Solved Deadlocks in Flexible Manufacturing Systems

NASA Astrophysics Data System (ADS)

Abdul-Hussin, Mowafak Hassan

2015-07-01

This article presents an approach to the constructing a class structural analysis of Petri nets, where elementary siphons are mainly used in the development of a deadlock control policy of flexible manufacturing systems (FMSs), that has been exploited successfully for the design of supervisors of some supervisory control problems. Deadlock-free operation of FMSs is significant objectives of siphons in the Petri net. The structure analysis of Petri net models has efficiency in control of FMSs, however different policy can be implemented for the deadlock prevention. Petri nets models based deadlock prevention for FMS's has gained considerable interest in the development of control theory and methods for design, controlling, operation, and performance evaluation depending of the special class of Petri nets called S3PR. Both structural analysis and reachability tree analysis is used for the purposes analysis, simulation and control of Petri nets. In our ex-perimental approach based to siphon is able to resolve the problem of deadlock occurred to Petri nets that are illustrated with an FMS.

Relation between SM-covers and SM-decompositions of Petri nets

NASA Astrophysics Data System (ADS)

Karatkevich, Andrei; Wiśniewski, Remigiusz

2015-12-01

A task of finding for a given Petri net a set of sequential components being able to represent together the behavior of the net arises often in formal analysis of Petri nets and in applications of Petri net to logical control. Such task can be met in two different variants: obtaining a Petri net cover or a decomposition. Petri net cover supposes that a set of the subnets of given net is selected, and the sequential nets forming a decomposition may have additional places, which do not belong to the decomposed net. The paper discusses difference and relations between two mentioned tasks and their results.

Colonisation of soilless growing media for tomato by Trichoderma harzianum.

PubMed

De Schutter, B; Aerts, R; Rombouts, L

2001-01-01

An experiment was conducted to evaluate the distribution of T. harzianum in soilless media used in greenhouse growing systems for tomatoes. Growing media based on rockwool and based on coconut fibre were included. The fungus was applied to the roots of the plant by means of a conidial suspension. The upper plant parts were removed from the coconut fibre an the rockwool slab after 10 and 15 weeks respectively. Both the coconut fibre and the rockwool slab were divided into fragments with a width of 10 cm. The coconut fibre medium fragments were again divided in an upper and a lower part. For every fragment the CFU/g was determined by two different methods. In the first method a known volume of growing medium was brought into suspension using a blender and diluted. Appropriate dilutions were plated on a selective medium. In the second method a known volume of growing medium was spread directly upon a selective medium in petri dishes. All dishes were incubated at room temperature and colonies were counted. Results showed that in the case of the coconut fibre growing medium T. harzianum was isolated in every fragment of the substrate. Highest densities were measured at the site of inoculation. In the lower part of the fragments less CFU/g were counted than in the upper part. In the case of the rockwool growing medium, there were several fragments in which no T. harzianum was isolated. The dilution technique demonstrated to be most useful in cases of high density. The direct spreading-method is best applied when low densities are expected. These observations demonstrate that the growing medium based upon coconut fibre is more appropriate for colonisation by T. harzianum. However, densities are higher at the site of inoculation in both tested growing media.

Generation of human secondary cardiospheres as a potent cell processing strategy for cell-based cardiac repair.

PubMed

Cho, Hyun-Jai; Lee, Ho-Jae; Chung, Yeon-Ju; Kim, Ju-Young; Cho, Hyun-Ju; Yang, Han-Mo; Kwon, Yoo-Wook; Lee, Hae-Young; Oh, Byung-Hee; Park, Young-Bae; Kim, Hyo-Soo

2013-01-01

Cell therapy is a promising approach for repairing damaged heart. However, there are large rooms to be improved in therapeutic efficacy. We cultured a small quantity (5-10 mg) of heart biopsy tissues from 16 patients who received heart transplantation. We produced primary and secondary cardiospheres (CSs) using repeated three-dimensional culture strategy and characterized the cells. Approximately 5000 secondary CSs were acquired after 45 days. Genetic analysis confirmed that the progenitor cells in the secondary CSs originated from the innate heart, but not from extra-cardiac organs. The expressions of Oct4 and Nanog were significantly induced in secondary CSs compared with adherent cells derived from primary CSs. Those expressions in secondary CSs were higher in a cytokine-deprived medium than in a cytokine-supplemented one, suggesting that formation of the three-dimensional structure was important to enhance stemness whereas supplementation with various cytokines was not essential. Signal blocking experiments showed that the ERK and VEGF pathways are indispensable for sphere formation. To optimize cell processing, we compared four different methods of generating spheres. Method based on the hanging-drop or AggreWell™ was superior to that based on the poly-d-lysine-coated dish or Petri dish with respect to homogeneity of the product, cellular potency and overall simplicity of the process. When transplanted into the ischemic myocardium of immunocompromised mice, human secondary CSs differentiated into cardiomyocytes and endothelial cells. These results demonstrate that generation of secondary CSs from a small quantity of adult human cardiac tissue is a feasible and effective cell processing strategy to improve the therapeutic efficacy of cell therapy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Optimal formation of genetically modified and functional pancreatic islet spheroids by using hanging-drop strategy.

PubMed

Kim, H J; Alam, Z; Hwang, J W; Hwang, Y H; Kim, M J; Yoon, S; Byun, Y; Lee, D Y

2013-03-01

Rejection and hypoxia are important factors causing islet loss at an early stage after pancreatic islet transplantation. Recently, islets have been dissociated into single cells for reaggregation into so-called islet spheroids. Herein, we used a hanging-drop strategy to form islet spheroids to achieve functional equivalence to intact islets. To obtain single islet cells, we dissociated islets with trypsin-EDTA digestion for 10 minutes. To obtain spheroids, we dropped various numbers of single cells (125, 250, or 500 cells/30 μL drop) onto a Petri dish, that was inverted for incubation in humidified air containing 5% CO(2) at 37 °C for 7 days. The aggregated spheroids in the droplets were harvested for further culture. The size of the aggregated islet spheroids depended on the number of single cells (125-500 cells/30 μL droplet). Their morphology was similar to that of intact islets without any cellular damage. When treated with various concentrations of glucose to evaluate responsiveness, their glucose-mediated stimulation index value was similar to that of intact islets, an observation that was attributed to strong cell-to-cell interactions in islet spheroids. However, islet spheroids aggregated in general culture dishes showed abnormal glucose responsiveness owing to weak cell-to-cell interactions. Cell-to-cell interactions in islet spheroids were confirmed with an anti-connexin-36 monoclonal antibody. Finally, nonviral poly(ethylene imine)-mediated interleukin-10 cytokine gene delivered beforehand into dissociated single cells before formation of islet spheroids increased the gene transfection efficacy and interleukin-10 secretion from islet spheroids >4-fold compared with intact islets. These results demonstrated the potential application of genetically modified, functional islet spheroids with of controlled size and morphology using an hanging-drop technique. Copyright © 2013 Elsevier Inc. All rights reserved.

A Petri Net Approach Based Elementary Siphons Supervisor for Flexible Manufacturing Systems

NASA Astrophysics Data System (ADS)

Abdul-Hussin, Mowafak Hassan

2015-05-01

This paper presents an approach to constructing a class of an S3PR net for modeling, simulation and control of processes occurring in the flexible manufacturing system (FMS) used based elementary siphons of a Petri net. Siphons are very important to the analysis and control of deadlocks of FMS that is significant objectives of siphons. Petri net models in the efficiency structure analysis, and utilization of the FMSs when different policy can be implemented lead to the deadlock prevention. We are representing an effective deadlock-free policy of a special class of Petri nets called S3PR. Simulation of Petri net structural analysis and reachability graph analysis is used for analysis and control of Petri nets. Petri nets contain been successfully as one of the most powerful tools for modelling of FMS, where Using structural analysis, we show that liveness of such systems can be attributed to the absence of under marked siphons.

Selection of Norway spruce somatic embryos by computer vision

NASA Astrophysics Data System (ADS)

Hamalainen, Jari J.; Jokinen, Kari J.

1993-05-01

A computer vision system was developed for the classification of plant somatic embryos. The embryos are in a Petri dish that is transferred with constant speed and they are recognized as they pass a line scan camera. A classification algorithm needs to be installed for every plant species. This paper describes an algorithm for the recognition of Norway spruce (Picea abies) embryos. A short review of conifer micropropagation by somatic embryogenesis is also given. The recognition algorithm is based on features calculated from the boundary of the object. Only part of the boundary corresponding to the developing cotyledons (2 - 15) and the straight sides of the embryo are used for recognition. An index of the length of the cotyledons describes the developmental stage of the embryo. The testing set for classifier performance consisted of 118 embryos and 478 nonembryos. With the classification tolerances chosen 69% of the objects classified as embryos by a human classifier were selected and 31$% rejected. Less than 1% of the nonembryos were classified as embryos. The basic features developed can probably be easily adapted for the recognition of other conifer somatic embryos.

Jupiter Fractal Art

NASA Image and Video Library

2017-08-10

See Jupiter's Great Red Spot as you've never seen it before in this new Jovian work of art. Artist Mik Petter created this unique, digital artwork using data from the JunoCam imager on NASA's Juno spacecraft. The art form, known as fractals, uses mathematical formulas to create art with an infinite variety of form, detail, color and light. The tumultuous atmospheric zones in and around the Great Red Spot are highlighted by the author's use of colorful fractals. Vibrant colors of various tints and hues, combined with the almost organic-seeming shapes, make this image seem to be a colorized and crowded petri dish of microorganisms, or a close-up view of microscopic and wildly-painted seashells. The original JunoCam image was taken on July 10, 2017 at 7:10 p.m. PDT (10:10 p.m. EDT), as the Juno spacecraft performed its seventh close flyby of Jupiter. The spacecraft captured the image from about 8,648 miles (13,917 kilometers) above the tops of the clouds of the planet at a latitude of -32.6 degrees. https://photojournal.jpl.nasa.gov/catalog/PIA21777

Induction of trap formation in nematode-trapping fungi by bacteria-released ammonia.

PubMed

Su, H N; Xu, Y Y; Wang, X; Zhang, K Q; Li, G H

2016-04-01

A total of 11 bacterial strains were assayed for bacteria-induced trap formation in the nematode-trapping fungus Arthrobotrys oligospora YMF1·01883 with two-compartmented Petri dish. These strains were identified on the basis of their 16S rRNA gene sequences. Volatile organic compounds (VOCs) of eight isolates were extracted using solid-phase micro-extraction (SPME) and their structures were identified based on gas chromatography-mass spectrometry (GC-MS). At the same time, all isolates were used for quantitative measurement of ammonia by the indophenol blue method. The effects of pure commercial compounds on inducement of trap formation in A. oligospora were tested. Taken together, results demonstrated that the predominant bacterial volatile compound inducing trap formation was ammonia. Meanwhile, ammonia also played a role in other nematode-trapping fungi, including Arthrobotrys guizhouensis YMF1·00014, producing adhesive nets; Dactylellina phymatopaga YMF1·01474, producing adhesive knobs; Dactylellina cionopaga YMF1·01472, producing adhesive columns and Drechslerella brochopaga YMF1·01829, producing constricting rings. © 2016 The Society for Applied Microbiology.

KSC-99pp0292

NASA Image and Video Library

1999-03-09

In the KSC Life Sciences Building, Hangar L, Cape Canaveral Air Station, Dr. Haig Keshishian checks fruit fly larvae in a petri dish. The larvae are part of an experiment that is a secondary payload on mission STS-93. The experiment will examine the effects of microgravity and space flight on the development of neural connections between specific motor neurons and their targets in muscle fibers. Dr. Keshishian, from Yale University, is the principle investigator for the experiment. The larvae will be contained in incubators that are part of a Commercial Generic Bioprocessing Apparatus (CGBA), which can start bioprocessing reactions by mixing or heating a sample and can also initiate multiple-step, sequential reactions in a technique called phased processing. The primary payload of mission STS-93 is the Chandra X-ray Observatory, which will allow scientists from around the world to see previously invisible black holes and high-temperature gas clouds, giving the observatory the potential to rewrite the books on the structure and evolution of our universe. The target launch date for STS-93 is July 9, aboard Space Shuttle Columbia, from Launch Pad 39B

Phytotoxicity testing of diesel-contaminated water using Petunia grandiflora Juss. Mix F1 and Marigold-Nemo Mix (Tagetes patula L.).

PubMed

Wante, Solomon Peter; Leung, David W M

2018-06-17

Tagetes patula (marigold) and Petunia grandiflora (petunia) have been shown to exhibit potential in phytoremediation of environmental pollutants including heavy metals and textile dyes. To investigate their phytoremediation potential of diesel, it was necessary to evaluate diesel phytotoxicity of these two ornamental plants. Marigold and petunia seeds were incubated, for 10 and 15 days, respectively, in deionised water contaminated with 0 to 4%, v/v, diesel in Petri dishes in a growth room with continuous lighting at 25 °C. It was found that as far as seed germination was concerned, petunia was less sensitive than marigold to 4% diesel in water. In contrast, petunia exhibited poorer seedling root growth than marigold in the presence of diesel contamination. This finding of differential sensitivity of these two ornamental plants to diesel-contaminated water during germination and seedling growth has not been reported before. Therefore, the implications of phytotoxicity evaluation and comparison between different species or genotypes of plants at both seed germination and postgermination seedling growth should both be taken into consideration in screening tolerant plants for phytoremediation.

Training stem cells for treatment of malignant brain tumors

PubMed Central

Li, Shengwen Calvin; Kabeer, Mustafa H; Vu, Long T; Keschrumrus, Vic; Yin, Hong Zhen; Dethlefs, Brent A; Zhong, Jiang F; Weiss, John H; Loudon, William G

2014-01-01

The treatment of malignant brain tumors remains a challenge. Stem cell technology has been applied in the treatment of brain tumors largely because of the ability of some stem cells to infiltrate into regions within the brain where tumor cells migrate as shown in preclinical studies. However, not all of these efforts can translate in the effective treatment that improves the quality of life for patients. Here, we perform a literature review to identify the problems in the field. Given the lack of efficacy of most stem cell-based agents used in the treatment of malignant brain tumors, we found that stem cell distribution (i.e., only a fraction of stem cells applied capable of targeting tumors) are among the limiting factors. We provide guidelines for potential improvements in stem cell distribution. Specifically, we use an engineered tissue graft platform that replicates the in vivo microenvironment, and provide our data to validate that this culture platform is viable for producing stem cells that have better stem cell distribution than with the Petri dish culture system. PMID:25258664

Survival and symbiotic effectivity of lyophilized root nodule bacteria.

PubMed

Küçük, C; Kivanç, M

2008-08-15

The study has been carried out under the greenhouse and laboratory conditions, using the lyophilization technique to determine the preserving possibilities of 3 native strain isolated from bean root nodules that been widely cultivated in Turkey and was defined as Rhizobium bacteria. The strains been developed separately in the Petri dishes with YMA (Yeast Extract Mannitol Agar) sown into lyophilization tubes containing skim milk, frozen at -85 degrees C and dehydrated at -55 degrees C with vacuum. According to the cultural counting results continued for 35 months after lyophilization, while the living cells in R11 strains and R12 strains found as 41 x 10(9) and 35.5 x 10(9) cell mL(-1), respectively, the best result was determined in the R13 strain as 51.5 x 10(9) cell mL(-1). In the greenhouse trials, the dry weight of plant's green parts, the number of nodules and total nitrogen amounts were evaluated. The tested strains were inoculated with bean varieties peculiar to themselves and the lyophilizated cultures gave similar results with the main cultures kept in tubes with YMA.

Effects of Three Fire-Suppressant Foams on the Germination and Physiological Responses of Plants

NASA Astrophysics Data System (ADS)

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Preparation and Photoacoustic Analysis of Cellular Vehicles Containing Gold Nanorods.

PubMed

Cavigli, Lucia; Tatini, Francesca; Borri, Claudia; Ratto, Fulvio; Centi, Sonia; Cini, Alberto; Lelli, Beatrice; Matteini, Paolo; Pini, Roberto

2016-05-02

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to their intense optical absorbance in the near-infrared window, low cytotoxicity and potential to home into tumors. However, their delivery to tumors still remains an issue. An innovative approach consists of the exploitation of the tropism of tumor-associated macrophages that may be loaded with gold nanorods in vitro. Here, we describe the preparation and the photoacoustic inspection of cellular vehicles containing gold nanorods. PEGylated gold nanorods are modified with quaternary ammonium compounds, in order to achieve a cationic profile. On contact with murine macrophages in ordinary Petri dishes, these particles are found to undergo massive uptake into endocytic vesicles. Then these cells are embedded in biopolymeric hydrogels, which are used to verify that the stability of photoacoustic conversion of the particles is retained in their inclusion into cellular vehicles. We are confident that these results may provide new inspiration for the development of novel strategies to deliver plasmonic particles to tumors.

High-throughput Raman chemical imaging for evaluating food safety and quality

NASA Astrophysics Data System (ADS)

Qin, Jianwei; Chao, Kuanglin; Kim, Moon S.

2014-05-01

A line-scan hyperspectral system was developed to enable Raman chemical imaging for large sample areas. A custom-designed 785 nm line-laser based on a scanning mirror serves as an excitation source. A 45° dichroic beamsplitter reflects the laser light to form a 24 cm x 1 mm excitation line normally incident on the sample surface. Raman signals along the laser line are collected by a detection module consisting of a dispersive imaging spectrograph and a CCD camera. A hypercube is accumulated line by line as a motorized table moves the samples transversely through the laser line. The system covers a Raman shift range of -648.7-2889.0 cm-1 and a 23 cm wide area. An example application, for authenticating milk powder, was presented to demonstrate the system performance. In four minutes, the system acquired a 512x110x1024 hypercube (56,320 spectra) from four 47-mm-diameter Petri dishes containing four powder samples. Chemical images were created for detecting two adulterants (melamine and dicyandiamide) that had been mixed into the milk powder.

Taming Self-Organization Dynamics to Dramatically Control Porous Architectures.

PubMed

Daly, Ronan; Sader, John E; Boland, John J

2016-03-22

We demonstrate templating of functional materials with unexpected and intricate micro- and nanostructures by controlling the condensation, packing, and evaporation of water droplets on a polymer solution. Spontaneous evaporation of a polymer solution induces cooling of the liquid surface and water microdroplet condensation from the ambient vapor. These droplets pack together and act as a template to imprint an entangled polymer film. This breath figure (BF) phenomenon is an example of self-organization that involves the long-range ordering of droplets. Equilibrium-based analysis provides many insights into contact angles and drop stability of individual drops, but the BF phenomenon remains poorly understood thus far, preventing translation to real applications. Here we investigate the dynamics of this phenomenon to separate out the competing influences and then introduce a modulation scheme to ultimately manipulate the water vapor-liquid equilibrium independently from the solvent evaporation. This approach to BF control provides insights into the mechanism, a rationale for microstructure design, and evidence for the benefits of dynamical control of self-organization systems. We finally present dramatically different porous architectures from this approach reminiscent of microscale Petri dishes, conical flasks, and test tubes.

Application of Fourier Transform Infrared (FTIR) Spectroscopy for Rapid Detection of Fumonisin B2 in Raisins.

PubMed

Heperkan, Dilek; Gökmen, Ece

2016-07-01

The aim of this study was to investigate the potential use of FTIR spectroscopy as a rapid screening method to detect fumonisin produced by Aspergillus niger. A. niger spore suspensions isolated from raisins were inoculated in Petri dishes prepared with sultana raisin or black raisin extracts containing agar and malt extract agar (MEA). After 9 days of incubation at 25°C, fumonisin B2 (FB2) production on each agar plate was determined by subjecting the agar plugs to IR spectroscopy. The presence of amino group (at 1636-1639 cm(-1)) was especially indicative of fumonisin production in MEA and the raisin extracts containing agar. The results were confirmed by HPLC analysis of the agar sample extracts after immunoaffinity column cleanup. It was determined that A. niger produced more FB2 in sultana raisins than in MEA, with no FB2 being produced in black raisin extract agar. This study demonstrated that proper sample preparation procedure followed by FTIR analysis is a useful technique for identifying toxigenic molds and their mycotoxin production in agricultural commodities.

In vitro differentiation of mouse embryonic stem (mES) cells using the hanging drop method.

PubMed

Wang, Xiang; Yang, Phillip

2008-07-23

Stem cells have the remarkable potential to develop into many different cell types. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, This promising of science is leading scientists to investigate the possibility of cell-based therapies to treat disease. When culture in suspension without antidifferentiation factors, embryonic stem cells spontaneously differentiate and form three-dimensional multicellular aggregates. These cell aggregates are called embryoid bodies(EB). Hanging drop culture is a widely used EB formation induction method. The rounded bottom of hanging drop allows the aggregation of ES cells which can provide mES cells a good environment for forming EBs. The number of ES cells aggregatied in a hanging drop can be controlled by varying the number of cells in the initial cell suspension to be hung as a drop from the lid of Petri dish. Using this method we can reproducibly form homogeneous EBs from a predetermined number of ES cells.

A modified MacConkey agar for selective enumeration of necrotoxigenic E. coli O55 and probiotic E. coli Nissle 1917.

PubMed

Splichalova, Alla; Splichal, Igor; Sonnenborn, Ulrich; Rada, Vojtech

2014-09-01

An agar selective enumeration of necrotoxigenic Escherichia coli O55 (NTEC2) and probiotic E. coli Nissle 1917, using modified MacConkey agar, was developed to study bacterial interference between these E. coli strains in a gnotobiotic piglet model. Replacement of lactose with saccharose in the agar enables the direct visual enumeration of red colonies of E. coli O55 and yellow colonies of E. coli Nissle 1917 that are co-cultured in the same Petri dish. A total of 336 colonies (168 for each color) were subjected to strain-specific PCR identification with LNA probes. Sensitivity, specificity, and positive and negative predictive values were 96.43%, 95.83%, 95.86% and 96.41% respectively in E. coli O55, and 98.21%, 97.02%, 97.06% and 98.19% respectively in E. coli Nissle 1917. Color-based enumeration of both E. coli strains in colonic contents and mesenteric lymph nodes homogenates of gnotobiotic piglets demonstrated the applicability of this method for the gnotobiotic piglet model of enteric diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid fibroblast activation in mammalian cells induced by silicon nanowire arrays.

PubMed

Ha, Qing; Yang, Gao; Ao, Zhuo; Han, Dong; Niu, Fenglan; Wang, Shutao

2014-07-21

Activated tumor-associated fibroblasts (TAFs) with abundant fibroblast activation protein (FAP) expression attract tremendous attention in tumor progression studies. In this work, we report a rapid 24 h FAP activation method for fibroblasts using silicon nanowires (SiNWs) as culture substrates instead of growth factors or chemokines. In contrast with cells cultured on flat silicon which rarely express FAP, SiNW cultivated cells exhibit FAP levels similar to those found in cancerous tissue. We demonstrated that activated cells grown on SiNWs maintain their viability and proliferation in a time-dependent manner. Moreover, environmental scanning electron microscopy (ESEM) and focused ion beam and scanning electron microscopy (FIB-SEM) analysis clearly revealed that activated cells on SiNWs adapt to the structure of their substrates by filling inter-wire cavities via filopodia in contrast to cells cultured on flat silicon which spread freely. We further illustrated that the expression of FAP was rarely detected in activated cells after being re-cultured in Petri dishes, suggesting that the unique structure of SiNWs may have a certain influence on FAP activation.

Three-Dimensional Cell Behavior in Microgels

NASA Astrophysics Data System (ADS)

Bhattacharjee, Tapomoy; Palmer, Glyn; Ghivizzani, Steven; Keselowsky, Benjamin; Sawyer, W. Gregory; Angelini, Thomas

The number of dimensions in which particles can freely move strongly influences the collective behavior that emerges from their individual fluctuations. Thus, in 2D systems of cells in petri-dishes, our growing understanding of collective migration may be insufficient to explain cell behavior in 3D tissues. To study cell behavior in 3D, polymer scaffolds are used. Contemporary designs of 3D cell growth scaffolds enable cell migration and proliferative expansion by incorporating of degradable motifs. Matrix degradation creates space for cells to move and proliferate. However, different cell types and experimental conditions require the design of different scaffolds to optimize degradation with specific cell behaviors. By contrast, liquid like solids made from packed microgels can yield under cell generated stresses, allowing for cell motion without the need for scaffold degradation. Moreover, the use of microgels as 3D culture media allows arranging cells in arbitrary structures, harvesting cells, and delivering drugs and nutrients. Preliminary data describing cell behavior in 3D microgel culture will be presented. This material is based on work supported by the National Science Foundation under Grant No. DMR-1352043.

Effects of three fire-suppressant foams on the germination and physiological responses of plants.

PubMed

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Pumps for microfluidic cell culture.

PubMed

Byun, Chang Kyu; Abi-Samra, Kameel; Cho, Yoon-Kyoung; Takayama, Shuichi

2014-02-01

In comparison to traditional in vitro cell culture in Petri dishes or well plates, cell culture in microfluidic-based devices enables better control over chemical and physical environments, higher levels of experimental automation, and a reduction in experimental materials. Over the past decade, the advantages associated with cell culturing in microfluidic-based platforms have garnered significant interest and have led to a plethora of studies for high throughput cell assays, organs-on-a-chip applications, temporal signaling studies, and cell sorting. A clear concern for performing cell culture in microfluidic-based devices is deciding on a technique to deliver and pump media to cells that are encased in a microfluidic device. In this review, we summarize recent advances in pumping techniques for microfluidic cell culture and discuss their advantages and possible drawbacks. The ultimate goal of our review is to distill the large body of information available related to pumps for microfluidic cell culture in an effort to assist current and potential users of microfluidic-based devices for advanced in vitro cellular studies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Isolation of Ovicidal Fungi from Fecal Samples of Captive Animals Maintained in a Zoological Park.

PubMed

Hernández, José A; Vázquez-Ruiz, Rosa A; Cazapal-Monteiro, Cristiana F; Valderrábano, Esther; Arroyo, Fabián L; Francisco, Iván; Miguélez, Silvia; Sánchez-Andrade, Rita; Paz-Silva, Adolfo; Arias, María S

2017-06-02

Abstract : There are certain saprophytic fungi in the soil able to develop an antagonistic effect against eggs of parasites. Some of these fungal species are ingested by animals during grazing, and survive in their feces after passing through the digestive tract. To identify and isolate ovicidal fungi in the feces of wild captive animals, a total of 60 fecal samples were taken from different wild animals kept captive in the Marcelle Natureza Zoological Park (Lugo, Spain). After the serial culture of the feces onto Petri dishes with different media, their parasicitide activity was assayed against eggs of trematodes ( Calicophoron daubneyi ) and ascarids ( Parascaris equorum ). Seven fungal genera were identified in the feces. Isolates from Fusarium , Lecanicillium , Mucor , Trichoderma , and Verticillium showed an ovicidal effect classified as type 3, because of their ability to adhere to the eggshell, penetrate, and damage permanently the inner embryo. Penicillium and Gliocladium developed a type 1 effect (hyphae attach to the eggshell but morphological damage was not provoked). These results provide very interesting and useful information about fungi susceptible for being used in biological control procedures against parasites.

Microfluidics with fluid walls.

PubMed

Walsh, Edmond J; Feuerborn, Alexander; Wheeler, James H R; Tan, Ann Na; Durham, William M; Foster, Kevin R; Cook, Peter R

2017-10-10

Microfluidics has great potential, but the complexity of fabricating and operating devices has limited its use. Here we describe a method - Freestyle Fluidics - that overcomes many key limitations. In this method, liquids are confined by fluid (not solid) walls. Aqueous circuits with any 2D shape are printed in seconds on plastic or glass Petri dishes; then, interfacial forces pin liquids to substrates, and overlaying an immiscible liquid prevents evaporation. Confining fluid walls are pliant and resilient; they self-heal when liquids are pipetted through them. We drive flow through a wide range of circuits passively by manipulating surface tension and hydrostatic pressure, and actively using external pumps. Finally, we validate the technology with two challenging applications - triggering an inflammatory response in human cells and chemotaxis in bacterial biofilms. This approach provides a powerful and versatile alternative to traditional microfluidics.The complexity of fabricating and operating microfluidic devices limits their use. Walsh et al. describe a method in which circuits are printed as quickly and simply as writing with a pen, and liquids in them are confined by fluid instead of solid walls.

Magnetostatic Field System for Uniform Cell Cultures Exposure

PubMed Central

Vergallo, Cristian; Piccoli, Claudia; Romano, Alberto; Panzarini, Elisa; Serra, Antonio; Manno, Daniela; Dini, Luciana

2013-01-01

The aim of the present work has been the design and the realization of a Magnetostatic Field System for Exposure of Cell cultures (MaFiSEC) for the uniform and the reproducible exposure of cell cultures to static magnetic fields (SMFs) of moderate magnetic induction. Experimental and computer-simulated physical measurements show that MaFiSEC: i) generates a SMF with magnetic induction that can be chosen in the range of 3 to 20 mT; ii) allows the uniform SMF exposure of cells growing in adhesion and in suspension; iii) is cheap and easy to use. The efficacy and reproducibility of MaFiSEC has been tested by comparing the biological effects exerted on isolated human lymphocytes by 72 h of exposure to a magnet (i.e. Neodymium Magnetic Disk, NMD) placed under the culture Petri dish. Lymphocytes morphology, viability, cell death, oxidative stress and lysosomes activity were the parameters chosen to evaluate the SMF biological effects. The continuous exposure of cells to a uniform SMF, achieved with MaFiSEC, allows highly reproducible biochemical and morphological data. PMID:23977284

Alterations in the Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene after Cultivation in the Human Spaceflight Environment

PubMed Central

Fajardo-Cavazos, Patricia; Leehan, Joshua D.; Nicholson, Wayne L.

2018-01-01

The effect of Bacillus subtilis exposure to the human spaceflight environment on growth, mutagenic frequency, and spectrum of mutations to rifampicin resistance (RifR) was investigated. B. subtilis cells were cultivated in Biological Research in Canister-Petri Dish Fixation Units (BRIC-PDFUs) on two separate missions to the International Space Station (ISS), dubbed BRIC-18 and BRIC-21, with matching asynchronous ground controls. No statistically significant difference in either growth or in the frequency of mutation to RifR was found in either experiment. However, nucleotide sequencing of the RifR regions of the rpoB gene from RifR mutants revealed dramatic differences in the spectrum of mutations between flight (FL) and ground control (GC) samples, including two newly discovered rpoB alleles in the FL samples (Q137R and L489S). The results strengthen the idea that exposure to the human spaceflight environment causes unique stresses on bacteria, leading to alterations in their mutagenic potential. PMID:29491852

Measurements of water molecule density by tunable diode laser absorption spectroscopy in dielectric barrier discharges with gas-water interface

NASA Astrophysics Data System (ADS)

Tachibana, Kunihide; Nakamura, Toshihiro; Kawasaki, Mitsuo; Morita, Tatsuo; Umekawa, Toyofumi; Kawasaki, Masahiro

2018-01-01

We measured water molecule (H2O) density by tunable diode-laser absorption spectroscopy (TDLAS) for applications in dielectric barrier discharges (DBDs) with a gas-water interface. First, the effects of water temperature and presence of gas flow were tested using a Petri dish filled with water and a gas injection nozzle. Second, the TDLAS system was applied to the measurements of H2O density in two types of DBDs; one was a normal (non-inverted) type with a dielectric-covered electrode above a water-filled counter electrode and the other was an inverted type with a water-suspending mesh electrode above a dielectric-covered counter electrode. The H2O density in the normal DBD was close to the density estimated from the saturated vapor pressure, whereas the density in the inverted DBD was about half of that in the former type. The difference is attributed to the upward gas flow in the latter type, that pushes the water molecules up towards the gas-water interface.

Phytotoxicity and fate of 1,1,2-trichloroethylene: a laboratory study.

PubMed

Inderjit; Asakawa, Chikako; Kakuta, Hideo

2003-06-01

1,1,2-Trichloroethylene (TCE), a chlorinated organic contaminant, poses serious environmental concerns. A study was conducted to evaluate the phytotoxicity of TCE to a crop species and its fate in vermiculite. Growth bioassays were carried out using carrot (Daucus carota L.) as the test species. Three different concentrations, 0.25, 0.50, and 1 ppm were used to evaluate phytotoxicity of TCE. When added to petri plates with cotton pads, TCE did not have any effect on carrot seedling growth. However, when added to vermiculite, it significantly suppressed growth. Shoot growth was inhibited only at the 1 ppm concentration. Recovery experiments were carried out to study the fate of TCE in vermiculite. A significant decline in the percent recovery was observed with time. Interestingly, TCE additional peaks (unknown organic molecules) were detected with declining concentrations. The available chloride ion concentration in vermiculite containing 1 ppm of TCE for 24 hr was significantly higher compared to control.

Optimal management of reconfigurable manufacturing system modeling with Petri nets developed three-dimensional - RPD3D

NASA Astrophysics Data System (ADS)

Teodor, F.; Marinescu, V.; Epureanu, A.

2016-11-01

Modeling of reconfigurable manufacturing systems would have done using existing Petri net types, but the complexity and dynamics of the new manufacturing system, mainly data reconfiguration feature, required looking for a more compact representation with many variables that to model as accurately not only the normal operation of the production system but can capture and model and reconfiguration process. Thus, it was necessary to create a new class of Petri nets, called RPD3D (Developed Petri nets with three dimensional) showing the name of both lineage (new class derived from Petri nets developed, created in 2000 by Prof. Dr. Ing Vasile Marinescu in his doctoral thesis) [1], but the most important of the new features defining (transformation from one 2D model into a 3D model).The idea was to introduce the classical model of a Petri third dimension to be able to overlay multiple levels (layers) formed in 2D or 3D Petri nets that interact with each other (receiving or giving commands to enable or disable the various modules together simulating the operation of reconfigurable manufacturing systems). The aim is to present a new type of Petri nets called RPD3D - Developed Petri three-dimensional model used for optimal control and simulation of reconfigurable manufacturing systems manufacture of products such systems.

The methodology for modeling queuing systems using Petri nets

NASA Astrophysics Data System (ADS)

Kotyrba, Martin; Gaj, Jakub; Tvarůžka, Matouš

2017-07-01

This papers deals with the use of Petri nets in modeling and simulation of queuing systems. The first part is focused on the explanation of basic concepts and properties of Petri nets and queuing systems. The proposed methodology for the modeling of queuing systems using Petri nets is described in the practical part. The proposed methodology will be tested on specific cases.

Topological analysis of metabolic networks based on petri net theory.

PubMed

Zevedei-Oancea, Ionela; Schuster, Stefan

2011-01-01

Petri net concepts provide additional tools for the modelling of metabolic networks. Here, the similarities between the counterparts in traditional biochemical modelling and Petri net theory are discussed. For example the stoichiometry matrix of a metabolic network corresponds to the incidence matrix of the Petri net. The flux modes and conservation relations have the T-invariants, respectively, P-invariants as counterparts. We reveal the biological meaning of some notions specific to the Petri net framework (traps, siphons, deadlocks, liveness). We focus on the topological analysis rather than on the analysis of the dynamic behaviour. The treatment of external metabolites is discussed. Some simple theoretical examples are presented for illustration. Also the Petri nets corresponding to some biochemical networks are built to support our results. For example, the role of triose phosphate isomerase (TPI) in Trypanosoma brucei metabolism is evaluated by detecting siphons and traps. All Petri net properties treated in this contribution are exemplified on a system extracted from nucleotide metabolism.

Topological analysis of metabolic networks based on Petri net theory.

PubMed

Zevedei-Oancea, Ionela; Schuster, Stefan

2003-01-01

Petri net concepts provide additional tools for the modelling of metabolic networks. Here, the similarities between the counterparts in traditional biochemical modelling and Petri net theory are discussed. For example the stoichiometry matrix of a metabolic network corresponds to the incidence matrix of the Petri net. The flux modes and conservation relations have the T-invariants, respectively, P-invariants as counterparts. We reveal the biological meaning of some notions specific to the Petri net framework (traps, siphons, deadlocks, liveness). We focus on the topological analysis rather than on the analysis of the dynamic behaviour. The treatment of external metabolites is discussed. Some simple theoretical examples are presented for illustration. Also the Petri nets corresponding to some biochemical networks are built to support our results. For example, the role of triose phosphate isomerase (TPI) in Trypanosoma brucei metabolism is evaluated by detecting siphons and traps. All Petri net properties treated in this contribution are exemplified on a system extracted from nucleotide metabolism.

Colored Petri net modeling and simulation of signal transduction pathways.

PubMed

Lee, Dong-Yup; Zimmer, Ralf; Lee, Sang Yup; Park, Sunwon

2006-03-01

Presented herein is a methodology for quantitatively analyzing the complex signaling network by resorting to colored Petri nets (CPN). The mathematical as well as Petri net models for two basic reaction types were established, followed by the extension to a large signal transduction system stimulated by epidermal growth factor (EGF) in an application study. The CPN models based on the Petri net representation and the conservation and kinetic equations were used to examine the dynamic behavior of the EGF signaling pathway. The usefulness of Petri nets is demonstrated for the quantitative analysis of the signal transduction pathway. Moreover, the trade-offs between modeling capability and simulation efficiency of this pathway are explored, suggesting that the Petri net model can be invaluable in the initial stage of building a dynamic model.

Ontology based standardization of Petri net modeling for signaling pathways.

PubMed

Takai-Igarashi, Takako

2005-01-01

Taking account of the great availability of Petri nets in modeling and analyzing large complicated signaling networks, semantics of Petri nets is in need of systematization for the purpose of consistency and reusability of the models. This paper reports on standardization of units of Petri nets on the basis of an ontology that gives an intrinsic definition to the process of signaling in signaling pathways.

Ontology based standardization of petri net modeling for signaling pathways.

PubMed

Takai-Igarashi, Takako

2011-01-01

Taking account of the great availability of Petri nets in modeling and analyzing large complicated signaling networks, semantics of Petri nets is in need of systematization for the purpose of consistency and reusability of the models. This paper reports on standardization of units of Petri nets on the basis of an ontology that gives an intrinsic definition to the process of signaling in signaling pathways.

Modeling of Electrocardiograph Telediagnosing System Based on Petri Net

NASA Astrophysics Data System (ADS)

Hu, Wensong; Li, Ming; Li, Lan

This paper analyzed the characteristics of the electrocardiograph telediagnosing system. Firstly, we introduce the system and Petri nets. Secondly, we built a topological diagram of this system. Then we use Petri nets to show the physical process of this system. Finally, we verified the model of the electrocardiograph telediagnosing system. With the help of model based on Petri nets, we analyzed the system performance and feasibility.

Algebraic properties of automata associated to Petri nets and applications to computation in biological systems.

PubMed

Egri-Nagy, Attila; Nehaniv, Chrystopher L

2008-01-01

Biochemical and genetic regulatory networks are often modeled by Petri nets. We study the algebraic structure of the computations carried out by Petri nets from the viewpoint of algebraic automata theory. Petri nets comprise a formalized graphical modeling language, often used to describe computation occurring within biochemical and genetic regulatory networks, but the semantics may be interpreted in different ways in the realm of automata. Therefore, there are several different ways to turn a Petri net into a state-transition automaton. Here, we systematically investigate different conversion methods and describe cases where they may yield radically different algebraic structures. We focus on the existence of group components of the corresponding transformation semigroups, as these reflect symmetries of the computation occurring within the biological system under study. Results are illustrated by applications to the Petri net modelling of intermediary metabolism. Petri nets with inhibition are shown to be computationally rich, regardless of the particular interpretation method. Along these lines we provide a mathematical argument suggesting a reason for the apparent all-pervasiveness of inhibitory connections in living systems.

Scheduling multirobot operations in manufacturing by truncated Petri nets

NASA Astrophysics Data System (ADS)

Chen, Qin; Luh, J. Y.

1995-08-01

Scheduling of operational sequences in manufacturing processes is one of the important problems in automation. Methods of applying Petri nets to model and analyze the problem with constraints on precedence relations, multiple resources allocation, etc. have been available in literature. Searching for an optimum schedule can be implemented by combining the branch-and-bound technique with the execution of the timed Petri net. The process usually produces a large Petri net which is practically not manageable. This disadvantage, however, can be handled by a truncation technique which divides the original large Petri net into several smaller size subnets. The complexity involved in the analysis of each subnet individually is greatly reduced. However, when the locally optimum schedules of the resulting subnets are combined together, it may not yield an overall optimum schedule for the original Petri net. To circumvent this problem, algorithms are developed based on the concepts of Petri net execution and modified branch-and-bound process. The developed technique is applied to a multi-robot task scheduling problem of the manufacturing work cell.

Software Tool Integrating Data Flow Diagrams and Petri Nets

NASA Technical Reports Server (NTRS)

Thronesbery, Carroll; Tavana, Madjid

2010-01-01

Data Flow Diagram - Petri Net (DFPN) is a software tool for analyzing other software to be developed. The full name of this program reflects its design, which combines the benefit of data-flow diagrams (which are typically favored by software analysts) with the power and precision of Petri-net models, without requiring specialized Petri-net training. (A Petri net is a particular type of directed graph, a description of which would exceed the scope of this article.) DFPN assists a software analyst in drawing and specifying a data-flow diagram, then translates the diagram into a Petri net, then enables graphical tracing of execution paths through the Petri net for verification, by the end user, of the properties of the software to be developed. In comparison with prior means of verifying the properties of software to be developed, DFPN makes verification by the end user more nearly certain, thereby making it easier to identify and correct misconceptions earlier in the development process, when correction is less expensive. After the verification by the end user, DFPN generates a printable system specification in the form of descriptions of processes and data.

Snoopy--a unifying Petri net framework to investigate biomolecular networks.

PubMed

Rohr, Christian; Marwan, Wolfgang; Heiner, Monika

2010-04-01

To investigate biomolecular networks, Snoopy provides a unifying Petri net framework comprising a family of related Petri net classes. Models can be hierarchically structured, allowing for the mastering of larger networks. To move easily between the qualitative, stochastic and continuous modelling paradigms, models can be converted into each other. We get models sharing structure, but specialized by their kinetic information. The analysis and iterative reverse engineering of biomolecular networks is supported by the simultaneous use of several Petri net classes, while the graphical user interface adapts dynamically to the active one. Built-in animation and simulation are complemented by exports to various analysis tools. Snoopy facilitates the addition of new Petri net classes thanks to its generic design. Our tool with Petri net samples is available free of charge for non-commercial use at http://www-dssz.informatik.tu-cottbus.de/snoopy.html; supported operating systems: Mac OS X, Windows and Linux (selected distributions).

ARG1 Functions in the Physiological Adaptation of Undifferentiated Plant Cells to Spaceflight.

PubMed

Zupanska, Agata K; Schultz, Eric R; Yao, JiQiang; Sng, Natasha J; Zhou, Mingqi; Callaham, Jordan B; Ferl, Robert J; Paul, Anna-Lisa

2017-11-01

Scientific access to spaceflight and especially the International Space Station has revealed that physiological adaptation to spaceflight is accompanied or enabled by changes in gene expression that significantly alter the transcriptome of cells in spaceflight. A wide range of experiments have shown that plant physiological adaptation to spaceflight involves gene expression changes that alter cell wall and other metabolisms. However, while transcriptome profiling aptly illuminates changes in gene expression that accompany spaceflight adaptation, mutation analysis is required to illuminate key elements required for that adaptation. Here we report how transcriptome profiling was used to gain insight into the spaceflight adaptation role of Altered response to gravity 1 (Arg1), a gene known to affect gravity responses in plants on Earth. The study compared expression profiles of cultured lines of Arabidopsis thaliana derived from wild-type (WT) cultivar Col-0 to profiles from a knock-out line deficient in the gene encoding ARG1 (ARG1 KO), both on the ground and in space. The cell lines were launched on SpaceX CRS-2 as part of the Cellular Expression Logic (CEL) experiment of the BRIC-17 spaceflight mission. The cultured cell lines were grown within 60 mm Petri plates in Petri Dish Fixation Units (PDFUs) that were housed within the Biological Research In Canisters (BRIC) hardware. Spaceflight samples were fixed on orbit. Differentially expressed genes were identified between the two environments (spaceflight and comparable ground controls) and the two genotypes (WT and ARG1 KO). Each genotype engaged unique genes during physiological adaptation to the spaceflight environment, with little overlap. Most of the genes altered in expression in spaceflight in WT cells were found to be Arg1-dependent, suggesting a major role for that gene in the physiological adaptation of undifferentiated cells to spaceflight. Key Words: ARG1-Spaceflight-Gene expression-Physiological adaptation-BRIC. Astrobiology 17, 1077-1111.

Influence of Temperature and Relative Humidity on the Insecticidal Efficacy of Metarhizium anisopliae against Larvae of Ephestia kuehniella (Lepidoptera: Pyralidae) on Wheat.

PubMed

Athanassiou, Christos G; Kavallieratos, Nickolas G; Rumbos, Christos I; Kontodimas, Demetrius C

2017-01-01

A series of laboratory bioassays were conducted for the evaluation of the insecticidal efficacy of an isolate of Metarhizium anisopliae (Metschnikoff) Sorokin (Ascomycota: Hypocreales) against larvae of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), under various temperature-relative humidity (r.h.) conditions. The fungus was applied at four doses (0, 8 × 106, 8 × 108, and 8 × 1010 conidia ml-1) on wheat and insect mortality was assessed after exposure of 1, 2, 7, and 14 d. Bioassays were conducted at three temperatures (20, 25, and 30 °C) and two r.h. levels (55 and 75%). Although complete control was not achieved in any case, the fungus provided a considerable level of insect control. Mortality of E. kuehniella larvae on wheat treated with M. anisopliae ranged between 41.1 and 93.3% after 14 d of exposure, whereas the respective mortality levels in control dishes never exceeded 28.3%. The increase of temperature resulted in most cases to higher efficacy, indicating that temperature is an important factor for the performance of the fungus. In contrast, in most cases r.h. did not significantly affect the efficacy of the fungus, at least for the humidity levels tested. © The Author 2017. Published by Oxford University Press on behalf of the Entomological Society of America.

Fault Diagnosis System of Wind Turbine Generator Based on Petri Net

NASA Astrophysics Data System (ADS)

Zhang, Han

Petri net is an important tool for discrete event dynamic systems modeling and analysis. And it has great ability to handle concurrent phenomena and non-deterministic phenomena. Currently Petri nets used in wind turbine fault diagnosis have not participated in the actual system. This article will combine the existing fuzzy Petri net algorithms; build wind turbine control system simulation based on Siemens S7-1200 PLC, while making matlab gui interface for migration of the system to different platforms.

CyberPetri at CDX 2016: Real-time Network Situation Awareness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arendt, Dustin L.; Best, Daniel M.; Burtner, Edwin R.

CyberPetri is a novel visualization technique that provides a flexible map of the network based on available characteristics, such as IP address, operating system, or service. Previous work introduced CyberPetri as a visualization feature in Ocelot, a network defense tool that helped security analysts understand and respond to an active defense scenario. In this paper we present a case study in which we use the CyberPetri visualization technique to support real-time situation awareness during the 2016 Cyber Defense Exercise.

Bi-directional transition nets

NASA Astrophysics Data System (ADS)

Staines, Anthony Spiteri

2017-06-01

Ordinary Petri nets are forward directed transition systems. Modern transition systems events and event flows are reversible. Hence modeling structures that reflect this are important. The creation of a bi-directional Petri net extends the modeling power of Petri nets. This work presents the successful implementation of a bi-directional transition net. Some toy examples in comparison to Petri nets are given showing the increased modeling power in a compacted form. The results show some interesting findings on how the expressive power of these structures has been increased.

Analysis hierarchical model for discrete event systems

NASA Astrophysics Data System (ADS)

Ciortea, E. M.

2015-11-01

The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

Behavior of sea urchin primary mesenchyme cells in artificial extracellular matrices.

PubMed

Katow, H

1986-02-01

The primary mesenchyme cells (PMCs) were separated from the mesenchyme blastulae of Pseudocentrotus depressus using differential adhesiveness of these cells to plastic Petri dishes. These cells were incubated in various artificial extracellular matrices (ECMs) including horse serum plasma fibronectin, mouse EHS sarcoma laminin, mouse EHS sarcoma type IV collagen, and porcine skin dermatan sulfate. The cell behavior was monitored by a time-lapse videomicrograph and analysed with a microcomputer. The ultrastructure of the artificial ECM was examined by transmission electron microscopy (TEM), while the ultrastructure of the PMCs was examined by scanning electron microscopy (SEM). The PMCs did not migrate in type IV collagen gel, laminin or dermatan sulfate matrix either with or without collagen gel, whereas PMCs in the matrix which was composed of fibronectin and collagen gel migrated considerably. However, the most active and extensive PMC migration was seen in the matrix which contained dermatan sulfate in addition to fibronectin and collagen gel. This PMC migration involved an increase not only of migration speed but also of proportion of migration-promoted cells. These results support the hypothesis that the mechanism of PMC migration involves fibronectin, collagen and sulfated proteoglycans which contain dermatan sulfate.

Effects of copper sulfate on seedlings of Prosopis pubescens (screwbean mesquite).

PubMed

Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

2014-01-01

Phytoextraction is an established method of removal of heavy metals from contaminated soils worldwide. Phytoextraction is most efficient if local plants are used in the contaminated site. We propose that Prosopis pubescens (Screw bean mesquite) would be a successful phytoextractor of copper in our local soils. In order to determine the feasibility of using Screw bean mesquite, we utilized inductively-coupled plasma-optical emission spectroscopy (ICP-OES) and elemental analysis to observe the uptake of copper and the effects on macro and micro nutrients within laboratory-grown seedlings. We have previously shown that P. pubescens is a hyperaccumulator of copper in soil-grown seedlings. Light and transmission electron microscopy demonstrated death of root cells and ultrastructural changes due to the presence of copper from 50 mg/L - 600 mg/L. Ultrastructural changes included plasmolysis, starch accumulation, increased vacuolation and swollen chloroplasts with disarranged thylakoid membranes in cotyledons. Inductively coupled plasma-optical emission spectroscopy analyses of macro- and micro-nutrients revealed that the presence of copper sulfate in the growth medium of Petri-dish grown Prosopis pubescens seedlings resulted in dramatic decreases of magnesium, potassium and phosphorus. At 500-600 mg/L of copper sulfate, a substantial increase of sulfur was present in roots.

[Isolation of Aspergillus tritici from internal environment (Chile): Ecological and clinical scope].

PubMed

Vieille Oyarzo, Peggy; Cruz Choappa, Rodrigo; Piontelli Laforet, Eduardo

2018-03-29

Indoor environments provide important protective habitats for humans, who live or work in them most of the time. Many of these environments lack ventilation, which affects the composition of microbial communities, especially that of the fungal community. The aim of this study is to report the isolation of Aspergillus section Candidi from indoor environments of the School of Medicine at Universidad de Valparaiso, Chile, and identification through morpho-physiological and molecular approaches. Their ecological and clinical features were highlighted. An environmental non-volumetric sampling was performed on PDA medium; 2 petri dishes were exposed in 10 different places to select the Aspergillus samples. Subcultures were performed on agar Czapek with yeast extract (CYA), malt extract agar (MEA) and creatin sacarose agar (CREA) media only for the morpho-physiological and later the molecular identification of white spore species. Of the 20 samples analyzed, one Aspergillus belonging to Candidi section was isolated. Based on its morphology and molecular features, it was classified as Aspergillustritici Mehrotra & Basu. Its ecology and medical relevance are reviewed and discussed. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Physical Evaluation of PVA/Chitosan Film Blends with Glycerine and Calcium Chloride

NASA Astrophysics Data System (ADS)

Nugraheni, A. D.; Purnawati, D.; Kusumaatmaja, A.

2018-04-01

PVA/chitosan film has been fabricated by using drop casting method. PVA/chitosan film is produced by dissolving 2% (w/v) PVA solution and 2% (w/v) chitosan solution. PVA/chitosan film is produced with weight ratio variation (w/w) 100/0, 75/25, 50/50 and 0/100. The film is fabricated using drop casting method in Petry dish with diameter 11 cm at room temperature and RH 50%–60% during seven days. The mechanical properties were characterized by using Universal Technical Machine (UTM) and UV-Vis to understand the physical properties of weight ratio (w/w) of PVA/Chitosan film by addition of plasticizer and calcium chloride. The film thickness tends to decrease with PVA content. The addition of chitosan will increase film thickness, and it will decrease swelling index, elongation (%), and transmittance of UV rays. The additions of plasticizer to PVA/Chitosan film will increase film thickness and elongation (%), and it will decrease swelling index, tensile strength and transmittance of UV rays. The crosslink of PVA/Chitosan film with calcium chloride will decrease film thickness, swelling index, elongation (%) and transmittance of UV rays, and increase tensile strength.

Use of computer code for dose distribution studies in A 60CO industrial irradiator

NASA Astrophysics Data System (ADS)

Piña-Villalpando, G.; Sloan, D. P.

1995-09-01

This paper presents a benchmark comparison between calculated and experimental absorbed dose values tor a typical product, in a 60Co industrial irradiator, located at ININ, México. The irradiator is a two levels, two layers system with overlapping product configuration with activity around 300kCi. Experimental values were obtanied from routine dosimetry, using red acrylic pellets. Typical product was Petri dishes packages, apparent density 0.13 g/cm3; that product was chosen because uniform size, large quantity and low density. Minimum dose was fixed in 15 kGy. Calculated values were obtained from QAD-CGGP code. This code uses a point kernel technique, build-up factors fitting was done by geometrical progression and combinatorial geometry is used for system description. Main modifications for the code were related with source sumilation, using punctual sources instead of pencils and an energy and anisotropic emission spectrums were included. Results were, for maximum dose, calculated value (18.2 kGy) was 8% higher than experimental average value (16.8 kGy); for minimum dose, calculated value (13.8 kGy) was 3% higher than experimental average value (14.3 kGy).

Spatial Distribution of Circadian Clock Phase in Aging Cultures of Neurospora crassa1

PubMed Central

Dharmananda, Subhuti; Feldman, Jerry F.

1979-01-01

Neurospora crassa has been utilized extensively in the study of circadian clocks. Previously, the clock in this organism has been monitored by observing the morphological and biochemical changes occurring at the growing front of cultures grown on solid medium. A method has been developed for assaying the clock in regions of the culture behind the growing front, where no apparent morphological changes occur during the circadian cycle. Using this assay with Petri dish cultures that were 2 to 7 days old, the presence of a functional circadian clock not only at the growing front but in all other regions of the culture as well was demonstrated. Furthermore, the entire culture is not in the same phase, but shows a gradient of phases which is a function of the length of time the clock in a given part of the culture has been free-running. This gradient may be the result of a somewhat longer period of the oscillator behind the growing front compared to that at the growing front. The phase differences within a single culture of interconnected mycelium demonstrate the absence of total internal synchronization between adjacent regions of the hyphae under these conditions. PMID:16660855

Guidelines for Microplate Selection in High Content Imaging.

PubMed

Trask, Oscar J

2018-01-01

Since the inception of commercialized automated high content screening (HCS) imaging devices in the mid to late 1990s, the adoption of media vessels typically used to house and contain biological specimens for interrogation has transitioned from microscope slides and petri dishes into multi-well microtiter plates called microplates. The early 96- and 384-well microplates commonly used in other high-throughput screening (HTS) technology applications were often not designed for optical imaging. Since then, modifications and the use of next-generation materials with improved optical clarity have enhanced the quality of captured images, reduced autofocusing failures, and empowered the use of higher power magnification objectives to resolve fine detailed measurements at the subcellular pixel level. The plethora of microplates and their applications requires practitioners of high content imaging (HCI) to be especially diligent in the selection and adoption of the best plates for running longitudinal studies or larger screening campaigns. While the highest priority in experimental design is the selection of the biological model, the choice of microplate can alter the biological response and ultimately may change the experimental outcome. This chapter will provide readers with background, troubleshooting guidelines, and considerations for choosing an appropriate microplate.

A modular suite of hardware enabling spaceflight cell culture research

NASA Technical Reports Server (NTRS)

Hoehn, Alexander; Klaus, David M.; Stodieck, Louis S.

2004-01-01

BioServe Space Technologies, a NASA Research Partnership Center (RPC), has developed and operated various middeck payloads launched on 23 shuttle missions since 1991 in support of commercial space biotechnology projects. Modular cell culture systems are contained within the Commercial Generic Bioprocessing Apparatus (CGBA) suite of flight-qualified hardware, compatible with Space Shuttle, SPACEHAB, Spacelab and International Space Station (ISS) EXPRESS Rack interfaces. As part of the CGBA family, the Isothermal Containment Module (ICM) incubator provides thermal control, data acquisition and experiment manipulation capabilities, including accelerometer launch detection for automated activation and thermal profiling for culture incubation and sample preservation. The ICM can accommodate up to 8 individually controlled temperature zones. Command and telemetry capabilities allow real-time downlink of data and video permitting remote payload operation and ground control synchronization. Individual cell culture experiments can be accommodated in a variety of devices ranging from 'microgravity test tubes' or standard 100 mm Petri dishes, to complex, fed-batch bioreactors with automated culture feeding, waste removal and multiple sample draws. Up to 3 levels of containment can be achieved for chemical fixative addition, and passive gas exchange can be provided through hydrophobic membranes. Many additional options exist for designing customized hardware depending on specific science requirements.

On the existence and stability of liquid water on the surface of mars today.

PubMed

Kuznetz, L H; Gan, D C

2002-01-01

The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and mass transfer coefficients or theoretical climate models. This research uses an experimental approach to determine the feasibility of liquid water under martian conditions, setting the stage for a more empirical approach to the question of life on Mars. Experiments were conducted in three parts: Liquid water's existence was confirmed by droplets observed under martian conditions in part 1; the evolution of frost melting on the surface of various rocks under martian conditions was observed in part 2; and the evaporation rate of water in Petri dishes under Mars-like conditions was determined and compared with the theoretical predictions of various investigators in part 3. The results led to the conclusion that liquid water can be stable for extended periods of time on the martian surface under present-day conditions.

[Bacteriological quality of air in a ward for sterile pharmaceutical preparations].

PubMed

Caorsi P, Beatriz; Sakurada Z, Andrea; Ulloa F, M Teresa; Pezzani V, Marcela; Latorre O, Paz

2011-02-01

An extremely clean area is required for preparation of sterile pharmaceutical compounds, in compliance with international standards, to minimize the probability of microbial contamination. To evaluate the bacteriological quality of the air in the Sterile Pharmaceutical Preparation Unit of the University of Chile's Clinical Hospital and to set up alerts and action levels of bacterial growth. We studied eight representative sites of our Unit on a daily basis from January to February 2005 and twice a week from June 2005 to February 2006. We collected 839 samples of air by impact in the Petri dish. 474 (56.5%) samples were positive; 17 (3.5%) of them had an inappropriate bacterial growth (2% of total samples). The samples from sites 1 and 2 (big and small biosafety cabinets) were negative. The countertop and transfer area occasionally exceeded the bacterial growth limits. The most frequently isolated bacteria were coagulase-negative staphylococci, Micrococcus spp and Corynebacterium spp, from skin microbiota, and Bacillus spp, an environmental bacteria. From a microbiological perspective, the air quality in our sterile preparation unit complied with international standards. Setting institutional alerts and action levels and appropriately identifying bacteria in sensitive areas permits quantification of the microbial load and application of preventive measures.

Seed germination of seven desert plants and implications for vegetation restoration

PubMed Central

Lai, Liming; Chen, Lijun; Jiang, Lianhe; Zhou, Jihua; Zheng, Yuanrun; Shimizu, Hideyuki

2016-01-01

Germination cues reflect the conditions under which a species is likely to succeed in recruitment. Therefore, knowledge of the seed germination characteristics of key plant species in desertified areas is essential for restoration. The aims of this study were to evaluate the seed germination responses of seven native species, and to explore the implications for vegetation restoration. Seeds of seven desert species were sown in Petri dishes and subjected to various temperature and light conditions. The seeds germinated well at day/night temperatures of 25/15 °C and 30/20 °C but poorly at 35/25 °C. Seeds germinated best in the dark, and final germination percentages of all species were strongly inhibited at a photon irradiance of 1000 µmol m−2 s−1. Based on these results and the environmental conditions of their natural habitat, Agropyron cristatum and Artemisia halodendron are best adapted to shifting sand dunes: Elymus dahuricus, Caragana korshinskii and C. microphylla for semi-fixed sand dunes: and Medicago sativa and Melilotus suaveolen for fixed sand dunes. If seeds are sown in early May, they will likely be buried in sand, and the precipitation and temperature conditions will be suitable for seedling survival. PMID:27179541

[Study on conditions of seed germination of Cistanche].

PubMed

Qiao, Xue-Yi; Wang, Hua-Lei; Guo, Yu-Hai

2007-09-01

To study the effect of fluridone concentration, stimulating period, temperature and salt on the seed germination of three species of Cistanche. The seeds were cultured in Petri dish, and the germination percentage was counted. The highest germination percentage was observed in Cistanche tubulosa, C. deserticola, C. sala seeds pre-treated by 0.1 mg x L(-1) fluridone for 24-29 h. The optimal temperature for the seeds germination of three species of Cistanche was at 20-30 degrees C, and the seeds did not germinate at sub-or supraoptimal temperatures (5 and 35 degrees C). The salt tolerance of C. sala seeds was strong, and the critical value of NaCl concentration was 0.04 mol x L(-1). By contrast, C. tubulosa and C. deserticola seeds were more sensitive to the salt stress, the critical value of NaCl concentration was 0.02 mol x L(-1). The optimal germination condition and the method of testing germination percentage of three species of Cistanche seeds are as follow: the seeds are pre-treated by 0.1 mg x L(-1) fluridone for 24 h and then cultured at 20-30 degrees C in salt solution which concentration is lower than 0.02 mol x L(-1).

Microfluidic chambers using fluid walls for cell biology.

PubMed

Soitu, Cristian; Feuerborn, Alexander; Tan, Ann Na; Walker, Henry; Walsh, Pat A; Castrejón-Pita, Alfonso A; Cook, Peter R; Walsh, Edmond J

2018-06-12

Many proofs of concept have demonstrated the potential of microfluidics in cell biology. However, the technology remains inaccessible to many biologists, as it often requires complex manufacturing facilities (such as soft lithography) and uses materials foreign to cell biology (such as polydimethylsiloxane). Here, we present a method for creating microfluidic environments by simply reshaping fluids on a substrate. For applications in cell biology, we use cell media on a virgin Petri dish overlaid with an immiscible fluorocarbon. A hydrophobic/fluorophilic stylus then reshapes the media into any pattern by creating liquid walls of fluorocarbon. Microfluidic arrangements suitable for cell culture are made in minutes using materials familiar to biologists. The versatility of the method is demonstrated by creating analogs of a common platform in cell biology, the microtiter plate. Using this vehicle, we demonstrate many manipulations required for cell culture and downstream analysis, including feeding, replating, cloning, cryopreservation, lysis plus RT-PCR, transfection plus genome editing, and fixation plus immunolabeling (when fluid walls are reconfigured during use). We also show that mammalian cells grow and respond to stimuli normally, and worm eggs develop into adults. This simple approach provides biologists with an entrée into microfluidics. Copyright © 2018 the Author(s). Published by PNAS.

On the existence and stability of liquid water on the surface of mars today

NASA Technical Reports Server (NTRS)

Kuznetz, L. H.; Gan, D. C.

2002-01-01

The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and mass transfer coefficients or theoretical climate models. This research uses an experimental approach to determine the feasibility of liquid water under martian conditions, setting the stage for a more empirical approach to the question of life on Mars. Experiments were conducted in three parts: Liquid water's existence was confirmed by droplets observed under martian conditions in part 1; the evolution of frost melting on the surface of various rocks under martian conditions was observed in part 2; and the evaporation rate of water in Petri dishes under Mars-like conditions was determined and compared with the theoretical predictions of various investigators in part 3. The results led to the conclusion that liquid water can be stable for extended periods of time on the martian surface under present-day conditions.

In vitro activity of natural and chemical products on sporulation of Eimeria species oocysts of chickens.

PubMed

Gadelhaq, Sahar M; Arafa, Waleed M; Abolhadid, Shawky M

2018-02-15

This study was designed to investigate the ability of two herbal extracts and different chemical substances to inhibit or disrupt sporulation of Eimeria species oocysts of the chickens. The two herbal extracts were Allium sativum (garlic) and Moringa olifiera while the chemical substances included commercial disinfectants and diclazuril. Field isolates of Eimeria oocysts were propagated in chickens to obtain a continuous source of oocysts. The collected unsporulated oocysts (10 5 oocysts/5 ml) were dispensed into 5 cm Petri dish. Three replicates were used for each treatment. The treated oocysts were incubated for 48 h at 25-29 °C and 80% relative humidity. The results showed that herbal extracts, the commercial recommended dose of Dettol, TH4, Phenol, Virkon ® S, and Diclazuril 20% have no effect on the sporulation. While Sodium hypochlorite showed a significant degree of sporulation inhibition reached to 49.67%. Moreover, 70% ethanol, and 10% formalin showed 100% sporulation inhibition. It was concluded that 70% ethanol and 10% formalin are the most effective methods to inhibit Eimeria species sporulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Target Host Finding by Steinernema feltiae and Heterorhabditis bacteriophora in the Presence of a Non-Target Insect Host.

PubMed

Powell, Jeff R; Webster, John M

2004-09-01

The ability of Steinernema feltiae or Heterorhabditis bacteriophora infective juveniles (IJ), when applied to the soil surface, to infect a Galleria mellonella larva at the base of a soil-filled cup (276 cm(3)) was evaluated in the presence and absence of 100 larvae of a non-target insect, the aphid midge Aphidoletes aphidimyza, near the soil surface. In all four trials with either S. feltiae or H. bacteriophora, A. aphidimyza presence did not affect the number of IJ finding and infecting a G. mellonella larva. Steinernema feltiae and H. bacteriophora IJ movement (as measured by the percentage of IJ aggregating on either side of an experimental arena) in the presence of one or many A. aphidimyza larvae was evaluated in agar- and soil-filled petri dishes, respectively. Infective juvenile movement in the presence of A. aphidimyza did not differ from random, indicating that IJ were not attracted to A. aphidimyza. It is suggested, therefore, that A. aphidimyza does not reduce IJ efficacy when these two forms of biological control agent are present together in a field situation even though it is known that A. aphidimyza is susceptible to IJ of these species.

[Isolation, identification and characterization of acid-producing strains from psychrotolerant biogas fermentation].

PubMed

Wan, Yongqing; Zhang, Wei; Mandlaa; Tian, Ruihua; Wang, Ruigang; Duan, Kaihong

2015-11-04

The aim of this study was to screen acid-producing strains from the broth of psychrotolerant biogas fermentation and evaluate the acid-producing character of them. Acid-producing strains were isolated by a medium with methyl red at 4 degrees C in Petri dishes and identified by morphology observation and 16S rRNA sequencing. Moreover, the ability of hydrolysis of starch, fermentation of carbohydrates, liquefaction of gelatin and production of catalase were studied. Two acid-producing strains (FJ-8 and FJ-15) were isolated. The result of the 16S rRNA phylogenetic tree shows that FJ-8 and FJ-15 belong to Pseudomonas sp. and Shewanella sp., respectively. Both FJ-8 and FJ-15 could hydrolyze starch, liquidize gelatin and produce catalase. The optimum temperature for acid-producing of FJ-8 and FJ-15 is 15 degrees C and 20 degrees C, respectively. After 10 days cultivation at 4 degrees C, the concentration of acetic acid was 792 mg/L and 966 mg/L of FJ-8 and FJ-15, respectively. The selected strains, FJ-8 and FJ-15, have the potential to produce acids at low temperature.

Intraguild Predation Responses in Two Aphidophagous Coccinellids Identify Differences among Juvenile Stages and Aphid Densities.

PubMed

Rondoni, Gabriele; Ielo, Fulvio; Ricci, Carlo; Conti, Eric

2014-12-08

(1) Intraguild predation (IGP) can occur among aphidophagous predators thus reducing their effectiveness in controlling crop pests. Among ladybirds, Coccinella septempunctata L. and Hippodamia variegata Goeze are the most effective predators upon Aphis gossypii Glov., which is an economically important pest of melon. Understanding their likelihood to engage in reciprocal predation is a key point for conservation of biological control. Here, we aim to investigate, under laboratory conditions, the level of IGP between the two above mentioned aphidophagous species. (2) Fourth-instars of the two species were isolated in petri dishes with combinations of different stages of the heterospecific ladybird and different densities of A. gossypii. The occurrence of IGP events was recorded after six hours. (3) C. septempunctata predated H. variegata at a higher rate than vice versa (70% vs. 43% overall). Higher density of the aphid or older juvenile stage of the IG-prey (22% of fourth instars vs. 74% of eggs and second instars) reduces the likelihood of predation. (4) To our knowledge, IGP between C. septempunctata and H. variegata was investigated for the first time. Results represent a baseline, necessary to predict the likelihood of IGP occurrence in the field.

Bactericidal effect of silver nanoparticles against propagation of Clavibacter michiganensis infection in Lycopersicon esculentum Mill.

PubMed

Rivas-Cáceres, Raymundo Rene; Luis Stephano-Hornedo, Jose; Lugo, Jorge; Vaca, Rocio; Del Aguila, Pedro; Yañez-Ocampo, Gustavo; Mora-Herrera, Martha Elena; Camacho Díaz, Luis Miguel; Cipriano-Salazar, Moisés; Alaba, Peter Adeniyi

2018-02-01

This study explored the use of silver nanoparticle as a bactericidal against the propagation of Clavibacter michiganensis onto tomatoes (Lycopersicon esculentum Mill). In Mexico, tomato production covers about 73% of the total vegetable production but it is affected by outbreak of bacteria canker caused by Clavibacter michiganensis subspecies michiganensis (Cmm). Silver ions possess inhibitor properties, bactericides and high specter antimicrobials. In this study, 6 groups of culture were prepared using 6 different petri dishes where silver nanoparticles of varying concentrations (120, 84, 48, 24, 12 and 0 μg) were added. Furthermore, each group was observed for 20 min, 1, 2, 12 and 24 h. The optimum concentration is 84 μg, which shows an average of 2 Cmm colonies after 20 min. Further increase to 120 μg shows no significant change. However, the average colonies was observed for 48 μg after 1, 2, 12, and 24 h. The obtained results indicate that silver nanoparticles are a promising inhibitor, bactericide and high a specter antimicrobial for treatment or prevention of Cmm. Copyright © 2017. Published by Elsevier Ltd.

Methodical aspects of rearing decapod larvae, Pagurus bernhardus (Paguridae) and Carcinus maenas (Portunidae)

NASA Astrophysics Data System (ADS)

Dawirs, R. R.

1982-12-01

Improved methods for experimental rearing of Pagurus bernhardus and Carcinus maenas larvae are presented. Isolated maintenance was found essential for reliable statistical evaluation of results obtained from stages older than zoea-1. Only by isolated rearing is it possible to calculate mean values ±95% confidence intervals of stage duration. Mean values (without confidence intervals) can only be given for group-reared larvae if mortality is zero. Compared to group rearing, isolated rearing led to better survival, shorter periods of development and stimulated growth. Due to different swimming behavior P. bernhardus zoeae needed larger water volumes than Carcinus maenas larvae. P. bernhardus zoeae were reared with best results when isolated in Petri dishes (ca. 50 ml). They fed on newly hatched brine shrimp nauplii ( Artemia spp.). P. bernhardus megalopa did not require any gastropod shell or substratum; it developed best in glass vials without any food. C. maenas larvae could be reared most sucessfully in glass vials (ca 20 ml) under a simulated day-night regime (LD 16:8); constant darkness had a detrimental effect on development, leading to prolonged stage-duration times. C. maenas larvae were fed a mixture of newly hatched brine shrimp naupli and rotifers ( Brachionus plicatilis).

Genetic stability of ectomycorrhizal fungi is not affected by cryopreservation at -130 °C or cold storage with repeated sub-cultivations over a period of 2 years.

PubMed

Crahay, Charlotte; Munaut, Françoise; Colpaert, Jan V; Huret, Stéphanie; Declerck, Stéphane

2017-08-01

Cryopreservation is considered the most reliable method for storage of filamentous fungi including ectomycorrhizal (ECM) fungi. A number of studies, however, have reported genetic changes in fungus cultures following cryopreservation. In the present study, the genetic stability of six ECM fungus isolates was analyzed using amplified fragment length polymorphism (AFLP). The isolates were preserved for 2 years either by cryopreservation (at -130 °C) or by storage at 4 °C with regular sub-cultivation. A third preservation treatment consisting of isolates maintained on Petri dishes at 22-23 °C for 2 years (i.e., without any sub-cultivation) was included and used as a control. The differences observed in AFLP patterns between the three preservation methods remained within the range of the total error generated by the AFLP procedure (6.85%). Therefore, cryopreservation at -130 °C and cold storage with regular sub-cultivation did not affect the genetic stability of the ECM fungus isolates, and both methods can be used for the routine storage of ECM fungus isolates over a period of 2 years.

Controlled release from a composite silicone/hydrogel membrane.

PubMed

Hu, Z; Wang, C; Nelson, K D; Eberhart, R C

2000-01-01

To enhance the drug uptake and release capacity of silicone rubber (SR), N-isopropylacrylamide (NIPA) hydrogel particles have been incorporated into a SR membrane. The NIPA particles were thoroughly blended with uncured SR with a certain ratio at room temperature. The mixture was then cast in a Petri dish to 1 mm thickness and cured 10 hours at 90 degrees C. The SR/NIPA composite gel can absorb water approximately equal to its dry weight. Brilliant blue, used as a mock drug, was loaded into the composite gel. Drug release increased exponentially to a final value that is temperature dependent: low at T> =34 degrees C, and high at T< 34 degrees C. This finding is because the hydrophobicity of NIPA changes with temperature. Pulsed release in response to temperature switching between 20 and 39 degrees C has been achieved. Drug uptake and release capability strongly depends upon the structure of the composite gel. The optimal range of NIPA composition is between 75 and 87% by volume. In the cited range, the NIPA particles form an interconnected network that provides a channel for diffusion of drug solution. The SR/NIPA composite gel has promising attributes as a wound dressing and other uses.

Epizootiological characteristics of viable bacteria and fungi in indoor air from porcine, chicken, or bovine husbandry confinement buildings

PubMed Central

Roque, Katharine; Lim, Gyeong-Dong; Jo, Ji-Hoon; Shin, Kyung-Min; Song, Eun-Seob; Gautam, Ravi; Kim, Chang-Yul; Lee, Kyungsuk; Shin, Seungwon; Yoo, Han-Sang; Heo, Yong

2016-01-01

Microorganisms found in bioaerosols from animal confinement buildings not only foster the risk of spreading diseases among livestock buildings, but also pose health hazards to farm workers and nearby residents. This study identified the various microorganisms present in the air of swine, chicken, and cattle farms with different kinds of ventilation conditions in Korea. Microbial air samples were collected onto Petri dishes with bacterial or fungal growth media using a cascade impactor. Endotoxin levels in total dust were determined by the limulus amebocyte lysate kinetic QCL method. Prevalent Gram-positive bacteria were Staphylococcus (S.) lentus, S. chromogenes, Bacillus (B.) cereus, B. licheniformis, and Enterococcus faecalis, while the dominant fungi and Gram-negative bacteria were Candida albicans and Sphingomonas paucimobilis, respectively. Considering no significant relationship between the indoor dust endotoxin levels and the isolation of Gram-negative bacteria from the indoor air, monitoring the indoor airborne endotoxin level was found to be also critical for risk assessment on health for animals or workers. The present study confirms the importance of microbiological monitoring and control on animal husbandry indoor air to ensure animal and worker welfare. PMID:27456779

Pathways of Pb and Mn observed in a 5-year longitudinal investigation in young children and environmental measures from an urban setting.

PubMed

Gulson, Brian; Mizon, Karen; Taylor, Alan; Korsch, Michael; Davis, J Michael; Louie, Honway; Wu, Michael; Gomez, Laura; Antin, Luminita

2014-08-01

We monitored 108 children ≤5 years on a 6-month basis for up to 5 years in a major urban setting. Samples (n ∼ 7000) included blood, urine, handwipes (interior, and after exterior playing), 6-day duplicate diet, drinking water, interior house and day care dust-fall accumulation using petri dishes, exterior dust-fall accumulation, exterior dust sweepings, paint, soil and urban air. The geometric mean blood Pb (PbB) was 2.1 μg/dL and blood Mn (MnB) was 10.0 μg/L. Following a path modelling approach, mixed model analyses for a fully adjusted model showed the strongest associations for PbB were with interior house dust and soil; for MnB there were no significant associations with any predictors. Predictor variables only explained 9% of the variance for Pb and 0.7% for Mn. Relationships between environmental measures and PbB in children are not straightforward; soil and dust sweepings contribute only about 1/5th of the amounts to PbB found in other studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Acaricidal activity and repellency of essential oil from Piper aduncum and its components against Tetranychus urticae.

PubMed

Araújo, Mário J C; Câmara, Cláudio A G; Born, Flávia S; Moraes, Marcílio M; Badji, César A

2012-06-01

The chemical composition of essential oil of leaves of Piper aduncum L., growing wild in a fragment of the Atlantic Rainforest biome in northeastern Brazil, was determined through gas chromatography-mass spectrometry. The acaricidal activity and repellency of the essential oil and its components [dillapiole (0.28 g/ml), α-humulene (0.016 g/ml), (E)-nerolidol (0.0007 g/ml) and β-caryophyllene (0.0021 g/ml)] were evaluated in the laboratory against adults of Tetranychus urticae Koch. The mites were more susceptible to the oil in fumigation tests (LC(50) = 0.01 μl/l of air) than in contact test with closed Petri dish (LC(50) = 7.17 μl/ml); mortality was reduced by approximately 50 % in the latter test. The repellent action of the oil and toxicity by fumigation and contact did not differ significantly from the positive control (eugenol). The repellent activity was attributed to the components (E)-nerolidol, α-humulene and β-caryophyllene, whereas toxicity by fumigation and contact was attributed to β-caryophyllene. The effect of Piper oil and the role of its components regarding host plant preference with a two-choice leaf disk test are also discussed.

Microgravity Effects on the Early Events of Biological Nitrogen Fixation in Medicago Truncatula: Results from the SyNRGE Experiment

NASA Astrophysics Data System (ADS)

Stutte, Gary W.; Roberts, Michael S.

2013-02-01

SyNRGE (Symbiotic Nodulation in a Reduced Gravity Environment) was a sortie mission on STS-135 in the Biological Research in Canisters (BRIC) hardware to study the effect of μg on a plant-microbe symbiosis resulting in biological nitrogen fixation. Medicago truncatula, a model species for the legume family, was inoculated with its bacterial symbiont, Sinorhizobium meliloti, to observe early biomolecular events associated with infection and nodulation in Petri Dish Fixation Units (PDFU’s). Two sets of experiments were conducted in orbit and in 24-hour delayed ground controls. Experiments were designed to determine if S. meliloti would infect M. truncatula and initiate biomolecular changes associated with nodule formation and if the μg environment altered the host plant and/or bacteria to induce nodule formation upon return to 1g. Initial analysis results demonstrate that the legumes and bacteria cultivated in μg have potential to develop a symbiotic interaction, but suggest that μg alters their ability to form nodules upon return to 1g. (Research supported by NASA ESMD/ Advance Capabilities Division grant NNX10AR09A)

Airborne Fungi in Sahara Dust Aerosols Reaching the Eastern Caribbean: I. Taxonomic Characterization by Morphological Features

NASA Astrophysics Data System (ADS)

Rivera-Denizard, O.; Betancourt, C.; Armstrong, R. A.; Detres, Y.

2003-12-01

A wide variety of microorganisms are dispersed into the Caribbean region due to the input of Saharan dust aerosols during the summer months. These microorganisms can cause diseases in plants and animals, and might be responsible for an increase incidence of asthma and respiratory diseases in this region. A PM 2.5 air sampling station was installed in Castle Bruce, Dominica from March through July of 2002. Fourteen filters were obtained by running the air sampler continuously for 24 hour periods. The samples were collected in sterile Teflon filters (47 mm in diameter, 0.2 um pore size), inoculated in Malt Extract Agar (MEA) with lactic acid and incubated at 29° C. Colonies were counted, isolated and cultured on separate Petri dishes. Fungal classification to the genus level used macroscopic features and microscopic evaluation. The Nomarski light microscopy technique was used for identification of reproductive structures. A total of 105 colonies were isolated. Six genera including Aspergillus, Penicillium, Cladosporium, Fusarium, Curvularia,and Nigrospora were identified. The protocol for the molecular characterization to species level is presented as the second part of this work.

Modeling Filamentous Cyanobacteria Reveals the Advantages of Long and Fast Trichomes for Optimizing Light Exposure

PubMed Central

Tamulonis, Carlos; Postma, Marten; Kaandorp, Jaap

2011-01-01

Cyanobacteria form a very large and diverse phylum of prokaryotes that perform oxygenic photosynthesis. Many species of cyanobacteria live colonially in long trichomes of hundreds to thousands of cells. Of the filamentous species, many are also motile, gliding along their long axis, and display photomovement, by which a trichome modulates its gliding according to the incident light. The latter has been found to play an important role in guiding the trichomes to optimal lighting conditions, which can either inhibit the cells if the incident light is too weak, or damage the cells if too strong. We have developed a computational model for gliding filamentous photophobic cyanobacteria that allows us to perform simulations on the scale of a Petri dish using over 105 individual trichomes. Using the model, we quantify the effectiveness of one commonly observed photomovement strategy—photophobic responses—in distributing large populations of trichomes optimally over a light field. The model predicts that the typical observed length and gliding speeds of filamentous cyanobacteria are optimal for the photophobic strategy. Therefore, our results suggest that not just photomovement but also the trichome shape itself improves the ability of the cyanobacteria to optimize their light exposure. PMID:21789215

An experiment to fly on mission STS-93 is prepared at Life Sciences Building, CCAS

NASA Technical Reports Server (NTRS)

1999-01-01

In the KSC Life Sciences Building, Hangar L, Cape Canaveral Air Station, Dr. Haig Keshishian checks fruit fly larvae in a petri dish. The larvae are part of an experiment that is a secondary payload on mission STS-93. The experiment will examine the effects of microgravity and space flight on the development of neural connections between specific motor neurons and their targets in muscle fibers. Dr. Keshishian, from Yale University, is the principle investigator for the experiment. The larvae will be contained in incubators that are part of a Commercial Generic Bioprocessing Apparatus (CGBA), which can start bioprocessing reactions by mixing or heating a sample and can also initiate multiple-step, sequential reactions in a technique called phased processing. The primary payload of mission STS-93 is the Chandra X-ray Observatory, which will allow scientists from around the world to see previously invisible black holes and high- temperature gas clouds, giving the observatory the potential to rewrite the books on the structure and evolution of our universe. The target launch date for STS-93 is July 9, aboard Space Shuttle Columbia, from Launch Pad 39B.

Laser capture microdissection: Big data from small samples

PubMed Central

Datta, Soma; Malhotra, Lavina; Dickerson, Ryan; Chaffee, Scott; Sen, Chandan K.; Roy, Sashwati

2015-01-01

Any tissue is made up of a heterogeneous mix of spatially distributed cell types. In response to any (patho) physiological cue, responses of each cell type in any given tissue may be unique and cannot be homogenized across cell-types and spatial co-ordinates. For example, in response to myocardial infarction, on one hand myocytes and fibroblasts of the heart tissue respond differently. On the other hand, myocytes in the infarct core respond differently compared to those in the peri-infarct zone. Therefore, isolation of pure targeted cells is an important and essential step for the molecular analysis of cells involved say in the progression of disease. Laser capture microdissection (LCM) is powerful to obtain a pure targeted cell subgroup, or even a single cell, quickly and precisely under the microscope, successfully tackling the problem of tissue heterogeneity in molecular analysis. This review presents an overview of LCM technology, the principles, advantages and limitations and its down-stream applications in the fields of proteomics, genomics and transcriptomics. With powerful technologies and appropriate applications, this technique provides unprecedented insights into cell biology from cells grown in their natural tissue habitat as opposed to those cultured in artificial petri dish conditions. PMID:25892148

Laser capture microdissection: Big data from small samples.

PubMed

Datta, Soma; Malhotra, Lavina; Dickerson, Ryan; Chaffee, Scott; Sen, Chandan K; Roy, Sashwati

2015-11-01

Any tissue is made up of a heterogeneous mix of spatially distributed cell types. In response to any (patho) physiological cue, responses of each cell type in any given tissue may be unique and cannot be homogenized across cell-types and spatial co-ordinates. For example, in response to myocardial infarction, on one hand myocytes and fibroblasts of the heart tissue respond differently. On the other hand, myocytes in the infarct core respond differently compared to those in the peri-infarct zone. Therefore, isolation of pure targeted cells is an important and essential step for the molecular analysis of cells involved in the progression of disease. Laser capture microdissection (LCM) is powerful to obtain a pure targeted cell subgroup, or even a single cell, quickly and precisely under the microscope, successfully tackling the problem of tissue heterogeneity in molecular analysis. This review presents an overview of LCM technology, the principles, advantages and limitations and its down-stream applications in the fields of proteomics, genomics and transcriptomics. With powerful technologies and appropriate applications, this technique provides unprecedented insights into cell biology from cells grown in their natural tissue habitat as opposed to those cultured in artificial petri dish conditions.

Borelli's lactritmel agar induces conidiation in rare-macroconidia producing dermatophytic fungi.

PubMed

Ilkit, Macit; Gümral, Ramazan; Döğen, Aylin

2012-10-01

Macroconidia are among the most important indicators used to identify dermatophytic fungi, but several do not usually sporulate and/or produce macroconidia on Sabouraud glucose agar. Specifically, Microsporum audouinii, M. ferrugineum, Trichophyton concentricum, T. schoenleinii, T. verrucosum, and T. violaceum (including T. soudanense and T. yaoundei) rarely form macroconidia and, therefore, cannot be easily identified. In this study, we investigated the production of macroconidia on nine common laboratory media, including Borelli's lactritmel agar (BLA), modified Borelli's lactritmel agar (MBLA), brain heart infusion agar (BHIA), Christensen's urease agar in Petri dishes (UPA), cornmeal dextrose agar (CMDA), Lowenstein-Jensen agar (LJA), malt extract agar (MEA), oatmeal agar (OA), and potato dextrose agar (PDA). The performance of these media was evaluated using 18 rare-macroconidia producing isolates, including representative of the six species mentioned above. All cultures in this study were incubated at 26°C on the bench, and conidia formation on each was investigated at 5, 10, 15, 20, 25, and 30 days of incubation. BLA apparently improved macroconidia production after 15 days and was the most useful nutrient agar medium to induce these phenotypic characters in daily practice, closely followed by OA, PDA, and MBLA.

Cryopreservation on a cryo-plate of Arundina graminifolia protocorms, dehydrated with silica gel and drying beads.

PubMed

Cordova, L B; Thammasiri, K

2016-01-01

There are various methods for the cryopreservation of plant material, with each biological specimen potentially requiring protocol optimization to maximize success. The aim of this study is to compare droplet-vitrification, encapsulation-dehydration, and the cryo-plate method for cryopreservation of protocorms of the orchid Arundina graminifolia, using silica gel and drying beads as the desiccation materials. The cryo-plate method included preculture of protocorms, developed from seeds, placed on aluminium cryo-plates and embedded in alginate gel. Cryo-plates were surface dried using sterile filter paper, placed in Petri dishes containing 50 g silica gel or 30 g drying beads in a laminar air-flow cabinet. Specimens on cryo-plates were dehydrated to 25 % moisture content, placed into 2 mL cryotubes and plunged directly into liquid nitrogen for 1 d. For cryopreservation, the cryo-plate method, involving dehydration with 30 g drying beads gave the highest regrowth (77 %), followed by the encapsulation-dehydration method with 30 g drying beads (64 % regrowth) and the droplet-vitrification method, following exposure to PVS2 solution for 20 min (33 % regrowth). Regrowth of cryopreserved protocorms using the cryo-plate method was rapid with the highest survival and regrowth.

[USE OF LASER RAMAN-LUMINESCENT TECHNOLOGIES FOR EVALUATION OF QUALITY OF MEAT PRODUCTS AND DETERMINATION OF THE DEGREE OF THEIR BACTERIAL CONTAMINATION].

PubMed

Kukushkin, V I; Satusheva, E V; Aleksandrov, M T; Morozova, O A; Pashkov, E P; Ambartsumyan, O A; Amosova, V A

2015-01-01

Determination of the effect of microorganisms on spoilage of meat products during various temperature regimes of storage by integral indexes of luminescent lines in their spectra and development of an algorithm of microorganism indication by an express method using laser Raman-luminescent spectroscopy. Minced meat from beef and pork was used. Determination of quantity of mesophilic aerobic and opportunistic-anaerobic microorganisms was carried out by serial 10-fold dilutions with subsequent parallel seeding into Rida count total 24 plates and Petri dishes with 5% blood agar. Sample study was carried out in luminescent software-hardware complex Enspectr L405 (a variant of Enspectr M software-hardware complexes). Meat spoilage was established to be caused to a large degree by Pseudomonas genus (P. fluorescens, P. putida, P. fragi et al.) bacterial growth. Raman-luminescent spectra of bacteria that compose microflora, characterizing and accompanying beef and pork spoilage, were measured and recorded into a database. The results obtained will allow to use this technique in the future for both express-indication and differentiation of microorganisms and express-evaluation of quality of meat products at all stages of their manufacturing, storage, transport and realization.

Manure derived biochar can successfully replace phosphate rock amendment in peatland restoration.

PubMed

Pouliot, Rémy; Hugron, Sandrine; Rochefort, Line; Godbout, Stéphane; Palacios, Joahnn H; Groeneveld, Elisabeth; Jarry, Isabelle

2015-07-01

Phosphate rock fertilization is commonly used in peatland restoration to promote the growth of Polytrichum strictum, a nurse plant which aids the establishment of Sphagnum mosses. The present study tested whether 1) phosphorus fertilization facilitates the germination of P. strictum spores and 2) biochar derived from local pig manure can replace imported phosphate rock currently used in peatland restoration. Various doses of biochar were compared to phosphate rock to test its effect directly on P. strictum stem regeneration (in Petri dishes in a growth chamber) and in a simulation of peatland restoration with the moss layer transfer technique (in mesocoms in a greenhouse). Phosphorus fertilization promoted the germination of P. strictum spores as well as vegetative stem development. Biochar can effectively replace phosphate rock in peatland restoration giving a new waste management option for rural regions with phosphorus surpluses. As more available phosphorus was present in biochar, an addition of only 3-9 g m(-2) of pig manure biochar is recommended during the peatland restoration process, which is less than the standard dose of phosphate rock (15 g m(-2)). Copyright © 2015 Elsevier Ltd. All rights reserved.

Relative tolerance of a range of Australian native plant species and lettuce to copper, zinc, cadmium, and lead.

PubMed

Lamb, Dane T; Ming, Hui; Megharaj, Mallavarapu; Naidu, Ravi

2010-10-01

The tolerance of wild flora to heavy-metal exposure has received very little research. In this study, the tolerance of four native tree species, four native grass species, and lettuce to copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) was investigated in a root-elongation study using Petri dishes. The results of these studies show a diverse range of responses to Cu, Zn, Cd, and Pb amongst the tested plant species. Toxicity among metals decreased in the following order: Cd ~ Cu > Pb > Zn. Metal concentrations resulting in a 50% reduction in growth (EC(50)) varied considerably, ranging from (microM) 30 (Dichanthium sericeum) to >2000 (Acacia spp.) for Cu; from 260 (Lactuca sativa) to 2000 (Acacia spp.) for Zn; from 27 (L. sativa) to 940 (Acacia holosericea) for Cd; and from 180 (L. sativa) to >1000 (Acacia spp.) for Pb. Sensitive native plant species identified included D. sericeum, Casuarina cunninghamiana, and Austrodanthonia caespitosa. However, L. sativa (lettuce) was also among the most sensitive to all four metals. Acacia species showed a high tolerance to metal exposure, suggesting that the Acacia genus shows potential for use in contaminated-site revegetation.

Cultivation of Staphylococcus epidermidis in the Human Spaceflight Environment Leads to Alterations in the Frequency and Spectrum of Spontaneous Rifampicin-Resistance Mutations in the rpoB Gene

PubMed Central

Fajardo-Cavazos, Patricia; Nicholson, Wayne L.

2016-01-01

Bacteria of the genus Staphylococcus are persistent inhabitants of human spaceflight habitats and represent potential opportunistic pathogens. The effect of the human spaceflight environment on the growth and the frequency of mutations to antibiotic resistance in the model organism Staphylococcus epidermidis strain ATCC12228 was investigated. Six cultures of the test organism were cultivated in biological research in canisters–Petri dish fixation units for 122 h on orbit in the International Space Station (ISS) as part of the SpaceX-3 resupply mission. Asynchronous ground controls (GCs) consisted of identical sets of cultures cultivated for 122 h in the ISS Environmental Simulator at Kennedy Space Center. S. epidermidis exhibited significantly lower viable counts but significantly higher frequencies of mutation to rifampicin (Rif) resistance in space vs. GC cultures. The spectrum of mutations in the rpoB gene leading to RifR was altered in S. epidermidis isolates cultivated in the ISS compared to GCs. The results suggest that the human spaceflight environment induces unique physiologic stresses on growing bacterial cells leading to changes in mutagenic potential. PMID:27446039

Cultivation of Staphylococcus epidermidis in the Human Spaceflight Environment Leads to Alterations in the Frequency and Spectrum of Spontaneous Rifampicin-Resistance Mutations in the rpoB Gene.

PubMed

Fajardo-Cavazos, Patricia; Nicholson, Wayne L

2016-01-01

Bacteria of the genus Staphylococcus are persistent inhabitants of human spaceflight habitats and represent potential opportunistic pathogens. The effect of the human spaceflight environment on the growth and the frequency of mutations to antibiotic resistance in the model organism Staphylococcus epidermidis strain ATCC12228 was investigated. Six cultures of the test organism were cultivated in biological research in canisters-Petri dish fixation units for 122 h on orbit in the International Space Station (ISS) as part of the SpaceX-3 resupply mission. Asynchronous ground controls (GCs) consisted of identical sets of cultures cultivated for 122 h in the ISS Environmental Simulator at Kennedy Space Center. S. epidermidis exhibited significantly lower viable counts but significantly higher frequencies of mutation to rifampicin (Rif) resistance in space vs. GC cultures. The spectrum of mutations in the rpoB gene leading to Rif(R) was altered in S. epidermidis isolates cultivated in the ISS compared to GCs. The results suggest that the human spaceflight environment induces unique physiologic stresses on growing bacterial cells leading to changes in mutagenic potential.

Allelopathic effects of ragweed (Ambrosia artemisiifolia L.) on cultivated plants.

PubMed

Lehoczky, E; Gólya, G; Szabó, R; Szalai, A

2011-01-01

During the past years ragweed has been coming to the forefront of interest in Hungary and in other European countries as well because its serious health risk. Results of the 5th National Weed Survey has proven that ragweed is the most important weed species on Hungarian field lands, its coverage shows a rising tendency in cereals moreover it not only occurs in cultivated plants. Allelopathic effects of aqueous extracts derived from different parts of ragweed plants (air dried leafy stems, seeds) on the germination and growth of other cultivated plants [maize (Zea mays L.), winter wheat (Triticum aestivum L.), rye (Secale cereale L.), oat (Avena sativa L.)] were studied. The extracts made for the trials were prepared with distilled water. Petri dishes were used for the germination experiments and distilled water was used as a control treatment. The seven days long experiment was carried out within a Binder-type thermostat under dark conditions. The germination percentage was checked in every two days and the growth of sprouts was evaluated after a week counting the germinated seeds and measuring the length of the radicle and plumule. The measured data were statistically analysed and the effect of extracts on germinating and length of sprouts were assessed.

Assessment of allelopathic properties of Aloe ferox Mill. on turnip, beetroot and carrot.

PubMed

Arowosegbe, Sunday; Afolayan, Anthony J

2012-01-01

Turnip (Brassica rapa var. rapa L.), beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are common vegetables in South Africa. The allelopathic potential of aqueous leaf and root extracts of Aloe ferox Mill.- a highly valued medicinal plant- was evaluated against seed germination and seedling growth of the three vegetables in Petri dish experiments. The extracts were tested at concentrations of 2, 4, 6, 8, and 10 mg/mL. Leaf extract concentrations above 4 mg/mL inhibited the germination of all the crops, while the root extract had no significant effect on germination irrespective of concentration. Interestingly, the lowest concentration of leaf extract stimulated root length elongation of beetroot by 31.71%. Other concentrations significantly inhibited both root and shoot growth of the vegetable crops except the turnip shoot. The most sensitive crop was carrot, with percentage inhibition ranging from 29.15 to 100% for root and shoot lengths. Lower percentage inhibition was observed for the root extract than the leaf extract against shoot growth of beetroot and carrot. The results from this study suggested the presence of allelochemicals mostly in the leaves of A. ferox that could inhibit the growth of the turnip, beetroot and carrot.

Teaching Petri Nets Using P3

ERIC Educational Resources Information Center

Gasevic, Dragan; Devedzic, Vladan

2004-01-01

This paper presents Petri net software tool P3 that is developed for training purposes of the Architecture and organization of computers (AOC) course. The P3 has the following features: graphical modeling interface, interactive simulation by single and parallel (with previous conflict resolution) transition firing, two well-known Petri net…

A Petri net controller for distributed hierarchical systems. Thesis

NASA Technical Reports Server (NTRS)

Peck, Joseph E.

1991-01-01

The solutions to a wide variety of problems are often best organized as a distributed hierarchical system. These systems can be graphically and mathematically modeled through the use of Petri nets, which can easily represent synchronous, asynchronous, and concurrent operations. This thesis presents a controller implementation based on Petri nets and a design methodology for the interconnection of distributed Petri nets. Two case studies are presented in which the controller operates a physical system, the Center for Intelligent Robotic Systems for Space Exploration Dual Arm Robotic Testbed.

Isomorphisms between Petri nets and dataflow graphs

NASA Technical Reports Server (NTRS)

Kavi, Krishna M.; Buckles, Billy P.; Bhat, U. Narayan

1987-01-01

Dataflow graphs are a generalized model of computation. Uninterpreted dataflow graphs with nondeterminism resolved via probabilities are shown to be isomorphic to a class of Petri nets known as free choice nets. Petri net analysis methods are readily available in the literature and this result makes those methods accessible to dataflow research. Nevertheless, combinatorial explosion can render Petri net analysis inoperative. Using a previously known technique for decomposing free choice nets into smaller components, it is demonstrated that, in principle, it is possible to determine aspects of the overall behavior from the particular behavior of components.

Fuzzy Petri nets to model vision system decisions within a flexible manufacturing system

NASA Astrophysics Data System (ADS)

Hanna, Moheb M.; Buck, A. A.; Smith, R.

1994-10-01

The paper presents a Petri net approach to modelling, monitoring and control of the behavior of an FMS cell. The FMS cell described comprises a pick and place robot, vision system, CNC-milling machine and 3 conveyors. The work illustrates how the block diagrams in a hierarchical structure can be used to describe events at different levels of abstraction. It focuses on Fuzzy Petri nets (Fuzzy logic with Petri nets) including an artificial neural network (Fuzzy Neural Petri nets) to model and control vision system decisions and robot sequences within an FMS cell. This methodology can be used as a graphical modelling tool to monitor and control the imprecise, vague and uncertain situations, and determine the quality of the output product of an FMS cell.

Automation of Presentation Record Production Based on Rich-Media Technology Using SNT Petri Nets Theory.

PubMed

Martiník, Ivo

2015-01-01

Rich-media describes a broad range of digital interactive media that is increasingly used in the Internet and also in the support of education. Last year, a special pilot audiovisual lecture room was built as a part of the MERLINGO (MEdia-rich Repository of LearnING Objects) project solution. It contains all the elements of the modern lecture room determined for the implementation of presentation recordings based on the rich-media technologies and their publication online or on-demand featuring the access of all its elements in the automated mode including automatic editing. Property-preserving Petri net process algebras (PPPA) were designed for the specification and verification of the Petri net processes. PPPA does not need to verify the composition of the Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are significantly generalized for the newly introduced class of the SNT Petri process and agent nets in this paper. The PLACE-SUBST and ASYNC-PROC algebraic operators are defined for this class of Petri nets and their chosen properties are proved. The SNT Petri process and agent nets theory were significantly applied at the design, verification, and implementation of the programming system ensuring the pilot audiovisual lecture room functionality.

Automation of Presentation Record Production Based on Rich-Media Technology Using SNT Petri Nets Theory

PubMed Central

Martiník, Ivo

2015-01-01

Rich-media describes a broad range of digital interactive media that is increasingly used in the Internet and also in the support of education. Last year, a special pilot audiovisual lecture room was built as a part of the MERLINGO (MEdia-rich Repository of LearnING Objects) project solution. It contains all the elements of the modern lecture room determined for the implementation of presentation recordings based on the rich-media technologies and their publication online or on-demand featuring the access of all its elements in the automated mode including automatic editing. Property-preserving Petri net process algebras (PPPA) were designed for the specification and verification of the Petri net processes. PPPA does not need to verify the composition of the Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are significantly generalized for the newly introduced class of the SNT Petri process and agent nets in this paper. The PLACE-SUBST and ASYNC-PROC algebraic operators are defined for this class of Petri nets and their chosen properties are proved. The SNT Petri process and agent nets theory were significantly applied at the design, verification, and implementation of the programming system ensuring the pilot audiovisual lecture room functionality. PMID:26258164

A versatile petri net based architecture for modeling and simulation of complex biological processes.

PubMed

Nagasaki, Masao; Doi, Atsushi; Matsuno, Hiroshi; Miyano, Satoru

2004-01-01

The research on modeling and simulation of complex biological systems is getting more important in Systems Biology. In this respect, we have developed Hybrid Function Petri net (HFPN) that was newly developed from existing Petri net because of their intuitive graphical representation and their capabilities for mathematical analyses. However, in the process of modeling metabolic, gene regulatory or signal transduction pathways with the architecture, we have realized three extensions of HFPN, (i) an entity should be extended to contain more than one value, (ii) an entity should be extended to handle other primitive types, e.g. boolean, string, (iii) an entity should be extended to handle more advanced type called object that consists of variables and methods, are necessary for modeling biological systems with Petri net based architecture. To deal with it, we define a new enhanced Petri net called hybrid functional Petri net with extension (HFPNe). To demonstrate the effectiveness of the enhancements, we model and simulate with HFPNe four biological processes that are diffcult to represent with the previous architecture HFPN.

Petri net based model of the body iron homeostasis.

PubMed

Formanowicz, Dorota; Sackmann, Andrea; Formanowicz, Piotr; Błazewicz, Jacek

2007-10-01

The body iron homeostasis is a not fully understood complex process. Despite the fact that some components of this process have been described in the literature, the complete model of the whole process has not been proposed. In this paper a Petri net based model of the body iron homeostasis is presented. Recently, Petri nets have been used for describing and analyzing various biological processes since they allow modeling the system under consideration very precisely. The main result presented in the paper is twofold, i.e., an informal description of the main part of the whole iron homeostasis process is described, and then it is also formulated in the formal language of Petri net theory. This model allows for a possible simulation of the process, since Petri net theory provides a lot of established analysis techniques.

Application of growing nested Petri nets for modeling robotic systems operating under risk

NASA Astrophysics Data System (ADS)

Sorokin, E. V.; Senkov, A. V.

2017-10-01

The paper studies the peculiarities of modeling robotic systems engaged in mining. Existing modeling mechanisms are considered, which are based on nested Petri nets, and a new formalism of growing Petri nets is presented that allows modeling robotic systems operating under risk. Modeling is provided both for the regular operation mode and for non-standard modes in which individual elements of the system can perform uncharacteristic functions. The example shows growing Petri nets that are used for modeling extraction of flat coal seams by a robotic system consisting of several different-type autonomous robots.

Task sequence planning in a robot workcell using AND/OR nets

NASA Technical Reports Server (NTRS)

Cao, Tiehua; Sanderson, Arthur C.

1991-01-01

An approach to task sequence planning for a generalized robotic manufacturing or material handling workcell is described. Given the descriptions of the objects in this system and all feasible geometric relationships among these objects, an AND/OR net which describes the relationships of all feasible geometric states and associated feasibility criteria for net transitions is generated. This AND/OR net is mapped into a Petri net which incorporates all feasible sequences of operations. The resulting Petri net is shown to be bounded and have guaranteed properties of liveness, safeness, and reversibility. Sequences are found from the reachability tree of the Petri net. Feasibility criteria for net transitions may be used to generate an extended Petri net representation of lower level command sequences. The resulting Petri net representation may be used for on-line scheduling and control of the system of feasible sequences. A simulation example of the sequences is described.

An assembly process model based on object-oriented hierarchical time Petri Nets

NASA Astrophysics Data System (ADS)

Wang, Jiapeng; Liu, Shaoli; Liu, Jianhua; Du, Zenghui

2017-04-01

In order to improve the versatility, accuracy and integrity of the assembly process model of complex products, an assembly process model based on object-oriented hierarchical time Petri Nets is presented. A complete assembly process information model including assembly resources, assembly inspection, time, structure and flexible parts is established, and this model describes the static and dynamic data involved in the assembly process. Through the analysis of three-dimensional assembly process information, the assembly information is hierarchically divided from the whole, the local to the details and the subnet model of different levels of object-oriented Petri Nets is established. The communication problem between Petri subnets is solved by using message database, and it reduces the complexity of system modeling effectively. Finally, the modeling process is presented, and a five layer Petri Nets model is established based on the hoisting process of the engine compartment of a wheeled armored vehicle.

Petri Nets - A Mathematical Formalism to Analyze Chemical Reaction Networks.

PubMed

Koch, Ina

2010-12-17

In this review we introduce and discuss Petri nets - a mathematical formalism to describe and analyze chemical reaction networks. Petri nets were developed to describe concurrency in general systems. We find most applications to technical and financial systems, but since about twenty years also in systems biology to model biochemical systems. This review aims to give a short informal introduction to the basic formalism illustrated by a chemical example, and to discuss possible applications to the analysis of chemical reaction networks, including cheminformatics. We give a short overview about qualitative as well as quantitative modeling Petri net techniques useful in systems biology, summarizing the state-of-the-art in that field and providing the main literature references. Finally, we discuss advantages and limitations of Petri nets and give an outlook to further development. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling of water treatment plant using timed continuous Petri nets

NASA Astrophysics Data System (ADS)

Nurul Fuady Adhalia, H.; Subiono, Adzkiya, Dieky

2017-08-01

Petri nets represent graphically certain conditions and rules. In this paper, we construct a model of the Water Treatment Plant (WTP) using timed continuous Petri nets. Specifically, we consider that (1) the water pump always active and (2) the water source is always available. After obtaining the model, the flow through the transitions and token conservation laws are calculated.

Petri nets SM-cover-based on heuristic coloring algorithm

NASA Astrophysics Data System (ADS)

Tkacz, Jacek; Doligalski, Michał

2015-09-01

In the paper, coloring heuristic algorithm of interpreted Petri nets is presented. Coloring is used to determine the State Machines (SM) subnets. The present algorithm reduces the Petri net in order to reduce the computational complexity and finds one of its possible State Machines cover. The proposed algorithm uses elements of interpretation of Petri nets. The obtained result may not be the best, but it is sufficient for use in rapid prototyping of logic controllers. Found SM-cover will be also used in the development of algorithms for decomposition, and modular synthesis and implementation of parallel logic controllers. Correctness developed heuristic algorithm was verified using Gentzen formal reasoning system.

Petri nets as a modeling tool for discrete concurrent tasks of the human operator. [describing sequential and parallel demands on human operators

NASA Technical Reports Server (NTRS)

Schumacher, W.; Geiser, G.

1978-01-01

The basic concepts of Petri nets are reviewed as well as their application as the fundamental model of technical systems with concurrent discrete events such as hardware systems and software models of computers. The use of Petri nets is proposed for modeling the human operator dealing with concurrent discrete tasks. Their properties useful in modeling the human operator are discussed and practical examples are given. By means of and experimental investigation of binary concurrent tasks which are presented in a serial manner, the representation of human behavior by Petri nets is demonstrated.

The equivalency between logic Petri workflow nets and workflow nets.

PubMed

Wang, Jing; Yu, ShuXia; Du, YuYue

2015-01-01

Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented.

A systematic petri net approach for multiple-scale modeling and simulation of biochemical processes.

PubMed

Chen, Ming; Hu, Minjie; Hofestädt, Ralf

2011-06-01

A method to exploit hybrid Petri nets for modeling and simulating biochemical processes in a systematic way was introduced. Both molecular biology and biochemical engineering aspects are manipulated. With discrete and continuous elements, the hybrid Petri nets can easily handle biochemical factors such as metabolites concentration and kinetic behaviors. It is possible to translate both molecular biological behavior and biochemical processes workflow into hybrid Petri nets in a natural manner. As an example, penicillin production bioprocess is modeled to illustrate the concepts of the methodology. Results of the dynamic of production parameters in the bioprocess were simulated and observed diagrammatically. Current problems and post-genomic perspectives were also discussed.

Quantitative petri net model of gene regulated metabolic networks in the cell.

PubMed

Chen, Ming; Hofestädt, Ralf

2011-01-01

A method to exploit hybrid Petri nets (HPN) for quantitatively modeling and simulating gene regulated metabolic networks is demonstrated. A global kinetic modeling strategy and Petri net modeling algorithm are applied to perform the bioprocess functioning and model analysis. With the model, the interrelations between pathway analysis and metabolic control mechanism are outlined. Diagrammatical results of the dynamics of metabolites are simulated and observed by implementing a HPN tool, Visual Object Net ++. An explanation of the observed behavior of the urea cycle is proposed to indicate possibilities for metabolic engineering and medical care. Finally, the perspective of Petri nets on modeling and simulation of metabolic networks is discussed.

The Equivalency between Logic Petri Workflow Nets and Workflow Nets

PubMed Central

Wang, Jing; Yu, ShuXia; Du, YuYue

2015-01-01

Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented. PMID:25821845

An advanced environment for hybrid modeling of biological systems based on modelica.

PubMed

Pross, Sabrina; Bachmann, Bernhard

2011-01-20

Biological systems are often very complex so that an appropriate formalism is needed for modeling their behavior. Hybrid Petri Nets, consisting of time-discrete Petri Net elements as well as continuous ones, have proven to be ideal for this task. Therefore, a new Petri Net library was implemented based on the object-oriented modeling language Modelica which allows the modeling of discrete, stochastic and continuous Petri Net elements by differential, algebraic and discrete equations. An appropriate Modelica-tool performs the hybrid simulation with discrete events and the solution of continuous differential equations. A special sub-library contains so-called wrappers for specific reactions to simplify the modeling process. The Modelica-models can be connected to Simulink-models for parameter optimization, sensitivity analysis and stochastic simulation in Matlab. The present paper illustrates the implementation of the Petri Net component models, their usage within the modeling process and the coupling between the Modelica-tool Dymola and Matlab/Simulink. The application is demonstrated by modeling the metabolism of Chinese Hamster Ovary Cells.

Modeling safety requirements of an FMS using Petri-nets

NASA Astrophysics Data System (ADS)

Hanna, Moheb M.; Buck, A. A.; Smith, R.

1993-08-01

This paper is concerned with the modelling of safety requirements using Petri nets as a tool to model and simulate a Flexible Manufacturing System (FMS). The FMS cell described comprises a pick and place robot, a multi-head drilling machine together with a vision system and illustrates how the hierarchical structure of Petri nets can be used to ensure that all fail- safe requirements are satisfied; block diagrams together with fully detailed example Petri nets are given. The work demonstrates the use of cell and robot control Petro nets together with robot subnets for the x, y and z axes and associated output nets; the control and output nets are linked together with a safety net. Individual machines are linked with the control and safety nets of an FMS at cell level. The paper also illustrates how a Petri net can act as a decision maker during image inspection and identifies the unsafe conditions that can arise within an FMS.

Realization of planning design of mechanical manufacturing system by Petri net simulation model

NASA Astrophysics Data System (ADS)

Wu, Yanfang; Wan, Xin; Shi, Weixiang

1991-09-01

Planning design is to work out a more overall long-term plan. In order to guarantee a mechanical manufacturing system (MMS) designed to obtain maximum economical benefit, it is necessary to carry out a reasonable planning design for the system. First, some principles on planning design for MMS are introduced. Problems of production scheduling and their decision rules for computer simulation are presented. Realizable method of each production scheduling decision rule in Petri net model is discussed. Second, the solution of conflict rules for conflict problems during running Petri net is given. Third, based on the Petri net model of MMS which includes part flow and tool flow, according to the principle of minimum event time advance, a computer dynamic simulation of the Petri net model, that is, a computer dynamic simulation of MMS, is realized. Finally, the simulation program is applied to a simulation exmple, so the scheme of a planning design for MMS can be evaluated effectively.

A new approach for modular robot system behavioral modeling: Base on Petri net and category theory

NASA Astrophysics Data System (ADS)

Zhang, Yun; Wei, Hongxing; Yang, Bo

2018-04-01

To design modular robot system, Petri nets and category theory are combined and the ability of simulation of Petri net is discussed. According to category theory, the method of describing the category of components in the dynamic characteristics of the system is deduced. Moreover, a modular robot system is analyzed, which provides a verifiable description of the dynamic characteristics of the system.

A New ’Availability-Payment’ Model for Pricing Performance-Based Logistics Contracts

DTIC Science & Technology

2014-04-30

maintenance network connected to the inventory and Original Equipment Manufacturer (OEM) used in this paper. The input to the Petri net in Figure 2 is the...contract structures. The model developed in this paper uses an affine controller to drive a discrete event simulator ( Petri net ) that produces...discrete event simulator ( Petri net ) that produces availability and cost measures. The model is used to explore the optimum availability assessment

Modeling biological gradient formation: combining partial differential equations and Petri nets.

PubMed

Bertens, Laura M F; Kleijn, Jetty; Hille, Sander C; Heiner, Monika; Koutny, Maciej; Verbeek, Fons J

2016-01-01

Both Petri nets and differential equations are important modeling tools for biological processes. In this paper we demonstrate how these two modeling techniques can be combined to describe biological gradient formation. Parameters derived from partial differential equation describing the process of gradient formation are incorporated in an abstract Petri net model. The quantitative aspects of the resulting model are validated through a case study of gradient formation in the fruit fly.

Parallel firing strategy on Petri nets: A review

NASA Astrophysics Data System (ADS)

Mavlankulov, Gairatzhan; Turaev, Sherzod; Zhumabaeva, Laula; Zhukabayeva, Tamara

2015-05-01

In this paper we review the recent results related on Petri net controlled grammars and the close related topics. Though the theme of regulated grammars is one of the classic topics in formal language theory, a Petri net controlled grammar is still interesting subject for the investigation for many reasons. This type of grammars can successfully be used in modeling new problems emerging in manufacturing systems, systems biology and other areas. Moreover, the graphically illustrability, the ability to represent both a grammar and its control in one structure, and the possibility to unify different regulated rewritings make this formalization attractive for the study. We also summarize the obtained results and propose a new conception such as parallel firing strategy on Petri Nets.

Chips of Hope: Neuro-Electronic Hybrids for Brain Repair

NASA Astrophysics Data System (ADS)

Ben-Jacob, Eshel

2010-03-01

The field of Neuro-Electronic Hybrids kicked off 30 years ago when researchers in the US first tweaked the technology of recording and stimulation of networks of live neurons grown in a Petri dish and interfaced with a computer via an array of electrodes. Since then, many researchers have searched for ways to imprint in neural networks new ``memories" without erasing old ones. I will describe our new generation of Neuro-Electronic Hybrids and how we succeeded to turn them into the first learning Neurochips - memory and information processing chips made of live neurons. To imprint multiple memories in our new chip we used chemical stimulation at specific locations that were selected by analyzing the networks activity in real time according to our new information encoding principle. Currently we develop new-generation of neuro chips using special carbon nano tubes (CNT). These electrodes enable to engineer the networks topology and efficient electrical interfacing with the neurons. This advance bears the promise to pave the way for building a new experimental platform for testing new drugs and developing new methods for neural networks repair and regeneration. Looking into the future, the development brings us a step closer towards the dream of Brain Repair by implementable Neuro-Electronic hybrid chips.

ATHENA, the Desktop Human "Body"

ScienceCinema

Iyer, Rashi; Harris, Jennifer

2018-05-18

Creating surrogate human organs, coupled with insights from highly sensitive mass spectrometry technologies, a new project is on the brink of revolutionizing the way we screen new drugs and toxic agents. ATHENA, the Advanced Tissue-engineered Human Ectypal Network Analyzer project team, is developing four human organ constructs - liver, heart, lung and kidney - that are based on a significantly miniaturized platform. Each organ component will be about the size of a smartphone screen, and the whole ATHENA "body" of interconnected organs would fit neatly on a desk. "By developing this 'homo minutus,' we are stepping beyond the need for animal or Petri dish testing: There are huge benefits in developing drug and toxicity analysis systems that can mimic the response of actual human organs," said Rashi Iyer, a senior scientist at Los Alamos National Laboratory, the lead laboratory on the five-year, $19 million multi-institutional effort. The project is supported by the Defense Threat Reduction Agency (DTRA). Some 40 percent of pharmaceuticals fail their clinical trials, Iyer noted, and there are thousands of chemicals whose effects on humans are simply unknown. Providing a realistic, cost-effective and rapid screening system such as ATHENA with high-throughput capabilities could provide major benefits to the medical field, screening more accurately and offering a greater chance of clinical trial success.

Sterilization of Escherichia coli O157:H7 using micro corona ionizer.

PubMed

Chua, Beelee; Son, Ahjeong

2014-06-01

We demonstrated in vitro sterilization of Escherichia coli O157:H7 bacteria on agar by a pin-between-planes micro corona ionizer. The gap between the pin and the grid was ~1.1 mm, the length of the grid was ~2.1 mm and the height was ~1.0 mm. The effective pin radius and discharge length were both approximated to be 200 μm. Ozone generation rates of ~2.3 × 10(-3) mg/s, ~2.7 × 10(-3) mg/s and ~3.5 × 10(-3) mg/s at 1,500 V were calculated for relative humidity (RH) of 35 %, 25 % and 10 % respectively. Analytical ozone generation rate increases as RH decreases and it is consistent with experimental observations. Using target and control petri dishes with E. coli plated agar, the sterilization capability of the micro corona ionizer at 37 °C for 24 h was evaluated. A ~60 % reduction in bacterial colony was shown with plate counting and its kill radius could be tuned from ~ 20 mm to ~5 mm by reducing the duty cycle from 100 % to 50 % with 30 min pulse width. The results suggested that the micro corona ionizer might be suitable as a tunable ozone source in wound dressing for chronic wound management.

Evaluation of sunlight-exposed pyrethroid-treated netting for the control of face fly and housefly (Diptera: Muscidae).

PubMed

Peck, George W; Ferguson, Holly J; LePage, Jane T; Hebert, Vincent R; O'Neal, Sally D; Walsh, Douglas B

2014-01-01

Face flies, Musca autumnalis De Geer (Diptera: Muscidae), and houseflies, Musca domestica L. (Diptera: Muscidae), have a significant impact on livestock and dairy production throughout North America. Pyrethroid insecticide efficacy can be affected by exposure to direct sunlight, and the rate of photodegradation is substrate and formulation dependent. Insecticide-treated netting (ITN) is finding new applications in crop and livestock production systems. A baseline study using long-duration no-choice assays has been carried out to gauge the effectiveness of ITN treated with β-cyfluthrin, λ-cyhalothrin and bifenthrin on face flies and houseflies. After 12 weeks in direct sunlight, ITN treated with β-cyfluthrin was still highly insecticidal to face flies and houseflies, producing 100% mortality in petri dish assays. However, sunlight reduced the insecticidal activity of λ-cyhalothrin, with 3% of face flies and 50% of houseflies surviving after exposure to ITN that had been deployed for 10 weeks. Insecticidal activity was greatly reduced on bifenthrin-treated netting, with 20% of face flies and 50% of houseflies surviving in assays with netting deployed for only 3 weeks. With careful choice of the pyrethroid applied, treated netting could be an important component of livestock integrated pest management programs focused on sustainable practices. © 2013 Society of Chemical Industry.

Scavenging by spiders (Araneae) and its relationship to pest management of the brown recluse spider.

PubMed

Vetter, Richard S

2011-06-01

Experiments reported in Sandidge (2003; Nature 426: 30) indicated that the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, preferred to scavenge dead prey over live prey and that the spiders were not detrimentally affected when fed insecticide-killed crickets. Extrapolations made in subsequent media coverage disseminating the results of this research made counter-intuitive statements that pesticide treatment in houses would increase brown recluse populations in homes. This information was presented as if the scavenging behavior was specialized in the brown recluse; however, it was more likely that this behavior has not been well studied in other species. To provide a comparison, the current laboratory study examined the likelihood of non-Loxosceles spiders to scavenge dead prey. Of 100 non-Loxosceles spiders that were tested (from 11 families, 24 genera, and at least 29 species from a variety of spider hunting guilds), 99 scavenged dead crickets when offered in petri dishes. Some of the spiders were webspinners in which real-world scavenging of dead prey is virtually impossible, yet they scavenge when given the opportunity. Therefore, scavenging is a flexible opportunistic predatory behavior that is spread across a variety of taxa and is not a unique behavior in brown recluses. These findings are discussed in relation to pest management practices.

In Vitro Lethal Activity of the Nematophagous Fungus Clonostachys rosea (Ascomycota: Hypocreales) against Nematodes of Five Different Taxa.

PubMed

Rodríguez-Martínez, Rosalia; Mendoza-de-Gives, Pedro; Aguilar-Marcelino, Liliana; López-Arellano, María Eugenia; Gamboa-Angulo, Marcela; Hanako Rosas-Saito, Greta; Reyes-Estébanez, Manuela; Guadalupe García-Rubio, Virginia

2018-01-01

This study was aimed to evaluate the in vitro lethal activity of the nematophagous fungi Clonostachys rosea against 5 nematodes species belonging to different taxa. Two groups of 35 Petri dishes (PD) each were divided into 5 series of 7 (PD). Group 1 (series 1, 2, 3, 4, and 5) contained only water agar; meanwhile group 2 plates (series 6, 7, 8, 9, and 10) contained C. rosea cultures growth on water agar. Every plate from the two groups was added with 500 nematodes corresponding to the following genera/specie: Haemonchus contortus , Caenorhabditis elegans, Rhabditis sp., Panagrellus redivivus , and Butlerius sp. After 5-day incubation at room temperature, free (nontrapped) larvae were recovered from plates using the Baermann funnel technique. Recovered nematodes were counted and compared with their proper controls. Results shown an important reduction percentage of the nematode population attributed to the fungal lethal activity as follows: H. contortus (L 3 ) 87.7%; C. elegans 94.7%; Rhabditis sp. 71.9%; P. redivivus 92.7%; and Butlerius sp. 100% ( p ≤ 0.05). The activity showed by C. rosea against the H. contortus can be crucial for further studies focused to the biological control of sheep haemonchosis, although the environmental impact against beneficial nematodes should be evaluated.

ATHENA, the Desktop Human "Body"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iyer, Rashi; Harris, Jennifer

2014-09-29

Creating surrogate human organs, coupled with insights from highly sensitive mass spectrometry technologies, a new project is on the brink of revolutionizing the way we screen new drugs and toxic agents. ATHENA, the Advanced Tissue-engineered Human Ectypal Network Analyzer project team, is developing four human organ constructs - liver, heart, lung and kidney - that are based on a significantly miniaturized platform. Each organ component will be about the size of a smartphone screen, and the whole ATHENA "body" of interconnected organs would fit neatly on a desk. "By developing this 'homo minutus,' we are stepping beyond the need formore » animal or Petri dish testing: There are huge benefits in developing drug and toxicity analysis systems that can mimic the response of actual human organs," said Rashi Iyer, a senior scientist at Los Alamos National Laboratory, the lead laboratory on the five-year, $19 million multi-institutional effort. The project is supported by the Defense Threat Reduction Agency (DTRA). Some 40 percent of pharmaceuticals fail their clinical trials, Iyer noted, and there are thousands of chemicals whose effects on humans are simply unknown. Providing a realistic, cost-effective and rapid screening system such as ATHENA with high-throughput capabilities could provide major benefits to the medical field, screening more accurately and offering a greater chance of clinical trial success.« less

ANALYSIS OF WHEAT ALLERGEN DISPERSED IN AIR BY THE ACTION OF THREE TYPES OF FLOUR SIFTER.

PubMed

Hashimoto, Hiroyuki; Yoshimitsu, Masato; Kiyota, Kyohei

2017-01-01

Since wheat flour, a cause of food allergy, tends to disperse rapidly in air, it can unintentionally mix other foods during the sieving process. Our aim was to analyze the dispersal of wheat flour dust in air in order to prevent unintentional mixing. We measured particle size distribution of wheat flour, photographed the scattered flour for 60 seconds every 10 seconds after sieving through three types of flour sifter, constructed a velocity vector diagram of flour dust dispersal by each type of sifter, and measured the distance of wheat allergen dispersal over 20 minutes using a petri dish and immunochromatographic test. The particles were mainly 14.2μm and 60.4μm in diameter and settled at terminal velocities of about 8mm/s and 150mm/s, respectively. Wheat flour particles of more than 60μm (released in air by sifting) dropped mainly in the perpendicular direction, while particles of less than 30μm remained suspended and traveled 5m after sifting by all flour sifters. Our results suggested that wheat flour dust dispersed by sifting (regardless of sifter) could unintentionally mix other foods. To prevent contamination, it is necessary to control the flow of air or sift flour in a separate room.

The moral status of the embryo: an attempt at an analysis with the aid of David Hume's ethics.

PubMed

Engel, J B; Hönig, A; Segerer, S; Häusler, S F M; Dietl, J; Djakovic, A

2010-12-01

This article applies the moral sentimentalism founded by David Hume to the moral status of the embryo. It will attempt to explain the paradoxical fact that in Germany abortion is common and socially accepted while preimplantation genetic diagnosis is banned with the aid of an approach based on moral sentimentalism. David Hume established the thesis that the human being is guided by the emotions and not by reason when making moral decisions. Scientific innovations often create a feeling of anxiety. Consequently, the initial moral judgment about it is negative. Due to this habit, the innovation is often accepted after a phase of indifference. This phenomenon has been observed in the case of heart transplantation, as well as for IVF. Consequently, the apparent contradiction in the varying degrees of the embryo's worthiness of protection in the womb and in the Petri dish is due to the simple fact that these are different stages of habituation. Therefore, the ethics of Hume cannot stipulate the embryo's moral status for once and for all; however, they can paradoxically raise the ongoing current debate to a more rational level through the insight that the underlying moral concepts are not based on reason alone. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Effect of volatile metabolites of dill, radish and garlic on growth of bacteria

NASA Astrophysics Data System (ADS)

Tirranen, L. S.; Borodina, E. V.; Ushakova, S. A.; Rygalov, V. Ye; Gitelson, J. I.

2001-07-01

In a model experiment plants were grown in sealed chambers on expanded clay aggregate under the luminance of 150 W/m 2 PAR and the temperature of 24°C. Seven bacterial strains under investigation, replicated on nutrient medium surface in Petri dishes, were grown in the atmosphere of cultivated plants. Microbial response was evaluated by the difference between colony size in experiment and in control. In control, bacteria grew in the atmosphere of clean air. To study the effect of volatile metabolites of various plant on microbial growth, the experimental data were compared with the background values defined for each individual experiment. Expanded clay aggregate, luminance, temperature and sealed chamber (without plants) for the background were the same. Volatile metabolites from 28-days old radish plants have been reliably established to have no effect on the growth of microbes under investigation. Metabolites of 30-days old dill and 50-days old garlic have been established to have reliable bacteriostatic effect on the growth of three bacterial strains. Dill and garlic have been found to have different range of effects of volatile substances on bacterial growth. Volatile metabolites of dill and garlic differed in their effect on the sensitivity spectrum of bacteria. An attempt has been made to describe the obtained data mathematically.

House dust fungal communities' characterization: a double take on the six by sixty by six (6 × 60 × 6) project

NASA Astrophysics Data System (ADS)

Amaro, Raquel; Coelho, Sónia D.; Pastorinho, M. Ramiro; Taborda-Barata, Luís; Vaz-Patto, Maria A.; Monteiro, Marisa; Nepomuceno, Miguel C. S.; Lanzinha, Joăo C. G.; Teixeira, Joăo P.; Pereira, Cristiana C.; Sousa, Ana C. A.

2016-11-01

Fungi are a group of microbes that are found with particular incidence in the indoor environment. Their direct toxicity or capability of generating toxic compounds has been associated with a large number of adverse health effects, such as infectious diseases and allergies. Given that in modern society people spend a large part of their time indoors; fungal communities' characterization of this environmental compartment assumes paramount importance in the comprehension of health effects. House dust is an easy to obtain, time-integrative matrix, being its use in epidemiological studies on human exposure to environmental contaminants highly recommended. Furthermore, dust can carry a great variety of fungal content that undergoes a large number of processes that modulate and further complexify human exposure. Our study aims to identify and quantify the fungal community on house dust samples collected using two different methodologies (an approach not often seen in the literature): active (vacuum cleaner bags) and passive sampling (dust settled in petri dishes). Sampling was performed as part of the ongoing 6 × 60 × 6 Project in which six houses from Covilhă (Portugal), with building dates representative of six decades, were studied for a period of sixty days.

Microinjection of CRISPR/Cas9 Protein into Channel Catfish, Ictalurus punctatus, Embryos for Gene Editing.

PubMed

Elaswad, Ahmed; Khalil, Karim; Cline, David; Page-McCaw, Patrick; Chen, Wenbiao; Michel, Maximilian; Cone, Roger; Dunham, Rex

2018-01-20

The complete genome of the channel catfish, Ictalurus punctatus, has been sequenced, leading to greater opportunities for studying channel catfish gene function. Gene knockout has been used to study these gene functions in vivo. The clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) system is a powerful tool used to edit genomic DNA sequences to alter gene function. While the traditional approach has been to introduce CRISPR/Cas9 mRNA into the single cell embryos through microinjection, this can be a slow and inefficient process in catfish. Here, a detailed protocol for microinjection of channel catfish embryos with CRISPR/Cas9 protein is described. Briefly, eggs and sperm were collected and then artificial fertilization performed. Fertilized eggs were transferred to a Petri dish containing Holtfreter's solution. Injection volume was calibrated and then guide RNAs/Cas9 targeting the toll/interleukin 1 receptor domain-containing adapter molecule (TICAM 1) gene and rhamnose binding lectin (RBL) gene were microinjected into the yolk of one-cell embryos. The gene knockout was successful as indels were confirmed by DNA sequencing. The predicted protein sequence alterations due to these mutations included frameshift and truncated protein due to premature stop codons.

Lithography-free nanofluidic concentrator based on droplets-on-demand system

NASA Astrophysics Data System (ADS)

Yu, Miao; Zhou, Hongbo; Yao, Shuhuai

2013-11-01

Biomarkers are usually low-abundance proteins in biofluids and below detection limit of conventional biosensors. Nanofluidic concentration devices allow efficient biomolecules trapping by utilizing ion concentration polarization near nanochannels. However, once the electric field is turned off, the electrokinetic concentration plug cannot maintain its concentration status and starts to diffuse. In order to maintain the high concentration and extract the concentrated sample for further analysis, a good approach is to encapsulate these plugs into water-in-oil droplets. Here we developed a nanofluidic concentrator based on droplet-on-demand generator to encapsulate concentrated sample in nL droplets. The lithography-free nanochannels were patterned by thermal cracking on the surface of PS Petri-dish. The resulting nanochannel arrays were 30 nm in depth. In combination with microchannels on PDMS, the micro-nano hybrid chip was developed. We used FITC solution to demonstrate that the chip significantly increased the sample concentration for more than 100 folds within 5 minutes. By tuning the pulsed pressure imposed by the solenoid valve connected to the concentration channel, the system can generate a desired volume of droplet with a target sample concentration at a prescribed time. This work was supported by the Research Grants Council of Hong Kong under General Research Fund (Grant No. 621110).

Dereplicating and Spatial Mapping of Secondary Metabolites from Fungal Cultures in Situ.

PubMed

Sica, Vincent P; Raja, Huzefa A; El-Elimat, Tamam; Kertesz, Vilmos; Van Berkel, Gary J; Pearce, Cedric J; Oberlies, Nicholas H

2015-08-28

Ambient ionization mass spectrometry techniques have recently become prevalent in natural product research due to their ability to examine secondary metabolites in situ. These techniques retain invaluable spatial and temporal details that are lost through traditional extraction processes. However, most ambient ionization techniques do not collect mutually supportive data, such as chromatographic retention times and/or UV/vis spectra, and this can limit the ability to identify certain metabolites, such as differentiating isomers. To overcome this, the droplet-liquid microjunction-surface sampling probe (droplet-LMJ-SSP) was coupled with UPLC-PDA-HRMS-MS/MS, thus providing separation, retention times, MS data, and UV/vis data used in traditional dereplication protocols. By capturing these mutually supportive data, the identity of secondary metabolites can be confidently and rapidly assigned in situ. Using the droplet-LMJ-SSP, a protocol was constructed to analyze the secondary metabolite profile of fungal cultures without any sample preparation. The results demonstrate that fungal cultures can be dereplicated from the Petri dish, thus identifying secondary metabolites, including isomers, and confirming them against reference standards. Furthermore, heat maps, similar to mass spectrometry imaging, can be used to ascertain the location and relative concentration of secondary metabolites directly on the surface and/or surroundings of a fungal culture.

1800 MHz in vitro exposure device for experimental studies on the effects of mobile communication systems.

PubMed

Ardoino, L; Lopresto, V; Mancini, S; Pinto, R; Lovisolo, G A

2004-01-01

A wire patch cell (WPC) operating at the uplink frequency band of GSM 1800 MHz has been designed for in vitro experiments with the aim of investigating the possible biological effects of electromagnetic radiation associated with cellular phones. The 1800 MHz WPC design is a direct descendant of the original 900 MHz WPC introduced by Laval et al. This system provides a homogeneous specific absorption rate distribution, using four 3.5 cm petri dishes simultaneously. Numerical dosimetry has been performed using a commercial code (CST Microwave Studio), in order to evaluate accurately the efficiency of the structure (in terms of W kg(-1) per 1 W input power) and the distribution in the chosen biological target. The numerical results have been confirmed by experimental measurements performed by measuring thermal increase due to a high power impulse. The efficiency of the structure is 1.25 +/- 25% W kg(-1) per 1 W input power higher than the efficiency of the 900 MHz WPC. A few adjustments have been made in order to use the WPC in a standard incubator and to avoid thermal increases related to the radio frequency exposure. This exposure system has been adopted for the experiments scheduled in the RAMP and GUARD projects (VFPE).

Microfluidic system for facilitated quantification of nanoparticle accumulation to cells under laminar flow

PubMed Central

Kusunose, Jiro; Zhang, Hua; Gagnon, M. Karen J.; Pan, Tingrui; Simon, Scott I.; Ferrara, Katherine W.

2012-01-01

The identification of novel, synthetic targeting ligands to endothelial receptors has led to the rapid development of targeted nanoparticles for drug, gene and imaging probe delivery. Central to development and optimization are effective models for assessing particle binding in vitro. Here, we developed a simple and cost effective method to quantitatively assess nanoparticle accumulation under physiologically-relevant laminar flow. We designed reversibly vacuum–sealed PDMS microfluidic chambers compatible with 35 mm petri dishes, which deliver uniform or gradient shear stress. These chambers have sufficient surface area for facile cell collection for particle accumulation quantitation through FACS. We tested this model by synthesizing and flowing liposomes coated with APN (KD ~ 300 µM) and VCAM-1-targeting (KD ~ 30 µM) peptides over HUVEC. Particle binding significantly increased with ligand concentration (up to 6 mol%) and decreased with excess PEG. While the accumulation of particles with the lower affinity ligand decreased with shear, accumulation of those with the higher affinity ligand was highest in a low shear environment (2.4 dyne/cm2), as compared with greater shear or the absence of shear. We describe here a robust flow chamber model that is applied to optimize the properties of 100 nm liposomes targeted to inflamed endothelium. PMID:22855121

Ammonia-nitrogen and Phosphate Reduction by Bio-Filter using Factorial Design

NASA Astrophysics Data System (ADS)

Kasmuri, Norhafezah; Ashikin Mat Damin, Nur; Omar, Megawati

2018-02-01

Untreated landfill leachate is known to have endangered the environment. As such new treatment must be sought to ensure its cost-effective and sustainable treatment. Thus this paper reports the effectiveness of bio-filter to remove pollutants. In this research, the reduction of nutrients concentration was evaluated in two conditions: using bio-filter and without bio-filter. Synthetic wastewater was used in the batch culture. It was conducted within 21 days in the initial mediums of 100 mg/L ammonia-nitrogen. The nitrification medium consisted of 100 mg/L of ammonia-nitrogen while the nitrite assay had none. The petri dish experiment was also conducted to observe the existence of any colony. The results showed 22% of ammonia- nitrogen reduction and 33% phosphate in the nitrification medium with the bio-filter. The outcome showed that the bio-filter was capable to reduce the concentration of pollutants by retaining the slow growing bacteria (AOB and NOB) on the plastic carrier surface. The factorial design was applied to study the effect of the initial ammonia-nitrogen concentration and duration on nitrite-nitrogen removal. Finally, a regression equation was produced to predict the rate of nitrite-nitrogen removal without conducting extended experiments and to reduce the number of trials experiment.

New method for determination of efficacy of health care personnel hand wash products.

PubMed Central

Mahl, M C

1989-01-01

A method of studying the effects of health care personnel hand wash products is described. The fingernail regions of the hands of volunteers are inoculated with a mixture of Escherichia coli and Serratia marcescens, and the areas are dried for a standard time. After routine hand washing, each fingernail region is individually scrubbed with an electric toothbrush which moves longitudinally to the handle into collection fluid contained in a petri dish. The test bacteria in the fluid are then enumerated. (Bacillus subtilis spores may be included as tracers to show degree of physical removal of the procedure.) This method has several advantages over the frequently used glove juice technique. Experimental designs with large numbers of volunteers, multiple sampling sites, and many hand wash products may be performed. Ten sampling sites (fingers) are available, versus the two gloved hands for testing products. (Efficiency is almost 100% in the recovery of spore tracers placed on the fingernails.) Many commercial health care personnel hand wash products containing antimicrobial agents substantive to the skin do not rapidly reduce numbers of inoculated bacteria in the fingernail regions to any greater extent than nonantimicrobial hand washes. Products containing isopropanol or ethanol are very effective in decreasing bacteria in areas around and under the fingernails. PMID:2685028

Effects of Withania somnifera and Ginkgo biloba on Neural Regeneration using Planarian Model

NASA Astrophysics Data System (ADS)

Singhal, M.; Brinker, R.

2016-12-01

Elderly populations and associated age-related diseases, including damaged peripheral and central neural systems, are increasing. Both systems are vital, and methods to sustain function are sought. The purpose of this experiment was to determine whether Withania somnifera (WS) and Ginkgo biloba (GB) extracts are conducive to planarian regeneration. After acclimation, brown planaria were cut across lateral nerve cord. Experimental groups were treated with 100μg WS or GB extract. Planarian length was measured and piece tested for negative phototaxis. In phototactic test, planaria were allowed 30 seconds to cross petri dish and stay under dark side. A positive response signified photoreceptor presence, indicating regeneration. Both GB and WS groups expressed more favorable cumulative regeneration rates than control group (97.31%, 71.44%, and 40.60% respectively). The null hypothesis (identical regeneration rates) was rejected (p-value ≈ 0.0375). Because phototactic data wasn't taken on days 4 and 5, there was no significant difference in average day of first phototactic response. Most WS and GB planaria first responded on day 6, suggesting that, had data been taken on days 4 and 5, both plant-treated groups would have exhibited even sooner responses than control. Future studies include quantifying regeneration via planarian locomotive velocity (pLMV) and other stereotypical responses.

Evaluation of the effect of clinostat rotation on pollen germination and tube development as a tool for selection of plants in Space

NASA Astrophysics Data System (ADS)

De Micco, Veronica; Scala, Michele; Aronne, Giovanna

2006-05-01

The choice of species and cultivar on which rely to sustain Close Loop Environmental Systems is generally approached by analysing the behaviour of plants in presence of stress (sporophytic selection). In this paper, we investigated the possibility to conduct the selection among genotypes in Space through the male gametophytic selection. Thus, we studied the effect of simulated microgravity on pollen germination and tube development of both woody and herbaceous crop species: Prunus armeniaca (apricot), P. dulcis (almond), Malus domestica (apple) and Vicia faba (broad bean). Pollen collected from just bloomed flowers was assessed for viability and incubated on the optimal growing medium in petri dishes both on a uni-axial clinostat and stationary in 1g. Then, pollen was observed under a light microscope to detect percent germination and growth direction. Histochemical analyses were performed to verify the presence and distribution of storage substances. Moreover, specific stainings and epifluorescent microscopy were applied to count nuclei, follow the migration of sperm cells and investigate the presence, size and morphology of callose plugs. Results showed that simulated microgravity affected pollen tube development. The different response showed by the various species indicates that male-gametophytic selection could be useful for the selection of plants in microgravity.

A simple eccentric stirred tank mini-bioreactor: mixing characterization and mammalian cell culture experiments.

PubMed

Bulnes-Abundis, David; Carrillo-Cocom, Leydi M; Aráiz-Hernández, Diana; García-Ulloa, Alfonso; Granados-Pastor, Marisa; Sánchez-Arreola, Pamela B; Murugappan, Gayathree; Alvarez, Mario M

2013-04-01

In industrial practice, stirred tank bioreactors are the most common mammalian cell culture platform. However, research and screening protocols at the laboratory scale (i.e., 5-100 mL) rely primarily on Petri dishes, culture bottles, or Erlenmeyer flasks. There is a clear need for simple-easy to assemble, easy to use, easy to clean-cell culture mini-bioreactors for lab-scale and/or screening applications. Here, we study the mixing performance and culture adequacy of a 30 mL eccentric stirred tank mini-bioreactor. A detailed mixing characterization of the proposed bioreactor is presented. Laser induced fluorescence (LIF) experiments and computational fluid dynamics (CFD) computations are used to identify the operational conditions required for adequate mixing. Mammalian cell culture experiments were conducted with two different cell models. The specific growth rate and the maximum cell density of Chinese hamster ovary (CHO) cell cultures grown in the mini-bioreactor were comparable to those observed for 6-well culture plates, Erlenmeyer flasks, and 1 L fully instrumented bioreactors. Human hematopoietic stem cells were successfully expanded tenfold in suspension conditions using the eccentric mini-bioreactor system. Our results demonstrate good mixing performance and suggest the practicality and adequacy of the proposed mini-bioreactor. Copyright © 2012 Wiley Periodicals, Inc.

Lens-free computational imaging of capillary morphogenesis within three-dimensional substrates

NASA Astrophysics Data System (ADS)

Weidling, John; Isikman, Serhan O.; Greenbaum, Alon; Ozcan, Aydogan; Botvinick, Elliot

2012-12-01

Endothelial cells cultured in three-dimensional (3-D) extracellular matrices spontaneously form microvessels in response to soluble and matrix-bound factors. Such cultures are common for the study of angiogenesis and may find widespread use in drug discovery. Vascular networks are imaged over weeks to measure the distribution of vessel morphogenic parameters. Measurements require micron-scale spatial resolution, which for light microscopy comes at the cost of limited field-of-view (FOV) and shallow depth-of-focus (DOF). Small FOVs and DOFs necessitate lateral and axial mechanical scanning, thus limiting imaging throughput. We present a lens-free holographic on-chip microscopy technique to rapidly image microvessels within a Petri dish over a large volume without any mechanical scanning. This on-chip method uses partially coherent illumination and a CMOS sensor to record in-line holographic images of the sample. For digital reconstruction of the measured holograms, we implement a multiheight phase recovery method to obtain phase images of capillary morphogenesis over a large FOV (24 mm2) with ˜1.5 μm spatial resolution. On average, measured capillary length in our method was within approximately 2% of lengths measured using a 10× microscope objective. These results suggest lens-free on-chip imaging is a useful toolset for high-throughput monitoring and quantitative analysis of microvascular 3-D networks.

Hydronopylformamides: Modification of the Naturally Occurring Compound (-)-β-Pinene to Produce Insect Repellent Candidates against Blattella germanica.

PubMed

Liao, Shengliang; Liu, Yan; Si, Hongyan; Xiao, Zhuanquan; Fan, Guorong; Chen, Shangxing; Wang, Peng; Wang, Zongde

2017-06-16

The development of a novel repellent plays an important role in the integrated control of Blattella germanica . A series of novel hydronopylformamides derivatives were synthesized from a naturally occurring compound (-)-β-pinene. The structures of these hydronopylformamides derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹H-NMR and 13 C-NMR), and electron impact mass spectrometry (EI-MS). Repellency of these hydronopylformamides derivatives against Blattella germanica was evaluated by the using petri dish arena method. The results showed that four derivatives (compounds 8a , 8b , 8c and 8e ) exhibited repellency against Blattella germanica at a concentration of 20 mg/mL. Compound 8a was the most active compound among these derivatives, where the repelling ratios of compound 8a against Blattella germanica were 66.10%, 50.46%, 48.26%, at concentrations of 20 mg/mL, 10 mg/mL, and 5 mg/mL, respectively. In addition, compound 8a showed better repellency than the traditional insect repellent N , N -diethyl-3-methylbenzamide (DEET), which indicated that compound 8a had a good application prospect in the prevention of Blattella germanica . This research hopes to promote the value-added utilization of (-)-β-pinene and the development of novel German cockroach repellents.

Nematicidal effect of rhizobacteria on plant-parasitic nematodes associated with vineyards.

PubMed

Aballay, E; Prodan, S; Zamorano, A; Castaneda-Alvarez, C

2017-07-01

The action of metabolites and exoenzymes from rhizobacteria on different plant-parasitic nematodes has an influence on the nematicidal efficacy of the microbe. Seven rhizobacteria, divided into two bacterial groups, were evaluated in vitro for nematicidal activity on Meloidogyne ethiopica and Xiphinema index. The direct effect of their filtrates on egg hatching and juveniles of M. ethiopica as well as mobile stages of X. index was evaluated during a 72-h period. The production of four exoenzymes and two metabolites associated with nematode mortality was investigated. Molecular characterization of three isolates was performed, and the physiological profiles and lipase activity of all isolates were obtained using the BIOLOG EcoPlate system. While chitinase and collagenase were measured using the BIOLOG MT2 plate system, protease, hydrogen cyanide and hydrogen sulphide were directly determined in Petri dishes. Nematode mobile stages exposure to the bacterial filtrate revealed a nematicidal effect up to 93.7% on X. Index and up to 83.3% on M. ethiopica. The control of egg hatching varied between 35 and 85%. A positive correlation was found between the mortality of both nematode mobile stages and the concerted activities of the bacterial enzymes as well as the level of the volatile metabolites. The nematicidal effect of rhizobacteria strains varies by nematode genera and among the developmental stages evaluated.

Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems

PubMed Central

Zhao, Jiangsan; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A.; Nakhforoosh, Alireza

2017-01-01

Abstract Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. PMID:28168270

Investigating Effects of Nano- to Micro-Ampere Alternating Current Stimulation on Trichophyton rubrum Growth.

PubMed

Kwon, Dong Rak; Kwon, Hyunjung; Lee, Woo Ram; Park, Joonsoo

2016-10-01

Fungi are eukaryotic microorganisms including yeast and molds. Many studies have focused on modifying bacterial growth, but few on fungal growth. Microcurrent electricity may stimulate fungal growth. This study aims to investigate effects of microcurrent electric stimulation on Trichophyton rubrum growth. Standard-sized inoculums of T. rubrum derived from a spore suspension were applied to potato dextrose cornmeal agar (PDACC) plates, gently withdrawn with a sterile pipette, and were applied to twelve PDACC plates with a sterile spreader. Twelve Petri dishes were divided into four groups. The given amperage of electric current was 500 nA, 2 µA, and 4 µA in groups A, B, and C, respectively. No electric current was given in group D. In the first 48 hours, colonies only appeared in groups A and B (500 nA and 2 µA exposure). Colonies in group A (500 nA) were denser. Group C (4 µA) plates showed a barely visible film of fungus after 96 hours of incubation. Fungal growth became visible after 144 hours in the control group. Lower intensities of electric current caused faster fungal growth within the amperage range used in this study. Based on these results, further studies with a larger sample size, various fungal species, and various intensities of electric stimulation should be conducted.

Bioremediation by composting of heavy oil refinery sludge in semiarid conditions.

PubMed

Marín, José A; Moreno, José L; Hernández, Teresa; García, Carlos

2006-06-01

The present work attempts to ascertain the efficacy of low cost technology (in our case, composting) as a bioremediation technique for reducing the hydrocarbon content of oil refinery sludge with a large total hydrocarbon content (250-300 g kg(-1)), in semiarid conditions. The oil sludge was produced in a refinery sited in SE Spain The composting system designed, which involved open air piles turned periodically over a period of 3 months, proved to be inexpensive and reliable. The influence on hydrocarbon biodegradation of adding a bulking agent (wood shavings) and inoculation of the composting piles with pig slurry (a liquid organic fertiliser which adds nutrients and microbial biomass to the pile) was also studied. The most difficult part during the composting process was maintaining a suitable level of humidity in the piles. The most effective treatment was the one in which the bulking agent was added, where the initial hydrocarbon content was reduced by 60% in 3 months, compared with the 32% reduction achieved without the bulking agent. The introduction of the organic fertiliser did not significantly improve the degree of hydrocarbon degradation (56% hydrocarbon degraded). The composting process undoubtedly led to the biodegradation of toxic compounds, as was demonstrated by ecotoxicity tests using luminescent bacteria and tests on plants in Petri dishes.

Rapid detection of frozen-then-thawed minced beef using multispectral imaging and Fourier transform infrared spectroscopy.

PubMed

Ropodi, Athina I; Panagou, Efstathios Z; Nychas, George-John E

2018-01-01

In recent years, fraud detection has become a major priority for food authorities, as fraudulent practices can have various economic and safety consequences. This work explores ways of identifying frozen-then-thawed minced beef labeled as fresh in a rapid, large-scale and cost-effective way. For this reason, freshly-ground beef was purchased from seven separate shops at different times, divided in fifteen portions and placed in Petri dishes. Multi-spectral images and FTIR spectra of the first five were immediately acquired while the remaining were frozen (-20°C) and stored for 7 and 32days (5 samples for each time interval). Samples were thawed and subsequently subjected to similar data acquisition. In total, 105 multispectral images and FTIR spectra were collected which were further analyzed using partial least-squares discriminant analysis and support vector machines. Two meat batches (30 samples) were reserved for independent validation and the remaining five batches were divided in training and test set (75 samples). Results showed 100% overall correct classification for test and external validation MSI data, while FTIR data yielded 93.3 and 96.7% overall correct classification for FTIR test set and external validation set respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Utilization of wastewater on seed germination and physioogical parameters of rice (Oryza sativa L.)

NASA Astrophysics Data System (ADS)

Huy, V.; Iwai, C. B.

2018-03-01

Due to increasing world population and demand, fresh water availability is becoming a limited resource. Reusing wastewater for agriculture has received attention since it contains nutrients, which are beneficial for growing crops. Even though wastewater can be used as the nutrient source for the plant, the toxicity of wastewater can still be a cause for concern and investigation. The main objective of this paper was to assess the effect of different sources of wastewater on the germination of Jasmine rice (KDML105), White rice (Phatum Thani 1), and Sticky rice (RD6) under laboratory conditions. Petri dish cultures were used with various concentrations (0, 50, and 100%) of wastewater collected from swine farm, aquaculture activity, and domestic. Seed germination, root length, shoot length, seed vigor index, fresh weight and dry weight were measured after each experiment. The results have shown that domestic wastewater and aquaculture activity wastewater did not decrease performance of Jasmine rice (KDML105), White rice (Phatum thani 1), and Sticky rice (RD6) while the germination of Jasmine rice (KDML105), White rice (Phatum thani 1), and Sticky rice (RD6) decreased when irrigated with swine farm wastewater. Therefore, using domestic and aquaculture activity wastewater for irrigation are suitable for growth of these crop.

Filamentous fungi isolated from sand and water of "Bairro Novo" and "Casa Caiada" beaches, Olinda, Pernambuco, Brazil.

PubMed

Gomes, D N F; Cavalcanti, M A Q; Fernandes, M J S; Lima, D M M; Passavante, J Z O

2008-08-01

Fungi comprehend a heterogeneous group of heterotrophic microorganisms that act as saprobes or parasites or, less frequently, as symbionts living in association with other organisms. They are cosmopolitan and important components of ecosystems. Considering the small number of Brazilian papers on the filamentous mycota in marine environments, and the need to improve knowledge of the diversity of these microfungi in "Casa Caiada" and "Bairro Novo" beaches, Olinda, PE, the aim of this work was to isolate and identify the fungi from sand and water samples of these ecosystems. Thirty two samplings of sand (surface and 20 cm deep) and water (surface and 1 m deep) were carried out during the dry and rainy seasons, in low and high tide. From each sand sample, a suspension was made with 50 g of sand diluted in 90 mL of sterilized distilled water. From each sand suspension and water sample, 0.5 mL was spread, in triplicate, onto Petri dishes containing Sabouraud Agar added of chloramphenicol. The plates were incubated at 28 degrees C (+/-2 degrees C). Fifty seven species were isolated, identified, and classified in 20 genera. Aspergillus and Penicillium were the most frequent genera in both sand and water, with a total of 11 and 19 species, respectively.

Modeling of the U1 snRNP assembly pathway in alternative splicing in human cells using Petri nets.

PubMed

Kielbassa, J; Bortfeldt, R; Schuster, S; Koch, I

2009-02-01

The investigation of spliceosomal processes is currently a topic of intense research in molecular biology. In the molecular mechanism of alternative splicing, a multi-protein-RNA complex - the spliceosome - plays a crucial role. To understand the biological processes of alternative splicing, it is essential to comprehend the biogenesis of the spliceosome. In this paper, we propose the first abstract model of the regulatory assembly pathway of the human spliceosomal subunit U1. Using Petri nets, we describe its highly ordered assembly that takes place in a stepwise manner. Petri net theory represents a mathematical formalism to model and analyze systems with concurrent processes at different abstraction levels with the possibility to combine them into a uniform description language. There exist many approaches to determine static and dynamic properties of Petri nets, which can be applied to analyze biochemical systems. In addition, Petri net tools usually provide intuitively understandable graphical network representations, which facilitate the dialog between experimentalists and theoreticians. Our Petri net model covers binding, transport, signaling, and covalent modification processes. Through the computation of structural and behavioral Petri net properties and their interpretation in biological terms, we validate our model and use it to get a better understanding of the complex processes of the assembly pathway. We can explain the basic network behavior, using minimal T-invariants which represent special pathways through the network. We find linear as well as cyclic pathways. We determine the P-invariants that represent conserved moieties in a network. The simulation of the net demonstrates the importance of the stability of complexes during the maturation pathway. We can show that complexes that dissociate too fast, hinder the formation of the complete U1 snRNP.

Modelling of Biometric Identification System with Given Parameters Using Colored Petri Nets

NASA Astrophysics Data System (ADS)

Petrosyan, G.; Ter-Vardanyan, L.; Gaboutchian, A.

2017-05-01

Biometric identification systems use given parameters and function on the basis of Colored Petri Nets as a modelling language developed for systems in which communication, synchronization and distributed resources play an important role. Colored Petri Nets combine the strengths of Classical Petri Nets with the power of a high-level programming language. Coloured Petri Nets have both, formal intuitive and graphical presentations. Graphical CPN model consists of a set of interacting modules which include a network of places, transitions and arcs. Mathematical representation has a well-defined syntax and semantics, as well as defines system behavioural properties. One of the best known features used in biometric is the human finger print pattern. During the last decade other human features have become of interest, such as iris-based or face recognition. The objective of this paper is to introduce the fundamental concepts of Petri Nets in relation to tooth shape analysis. Biometric identification systems functioning has two phases: data enrollment phase and identification phase. During the data enrollment phase images of teeth are added to database. This record contains enrollment data as a noisy version of the biometrical data corresponding to the individual. During the identification phase an unknown individual is observed again and is compared to the enrollment data in the database and then system estimates the individual. The purpose of modeling biometric identification system by means of Petri Nets is to reveal the following aspects of the functioning model: the efficiency of the model, behavior of the model, mistakes and accidents in the model, feasibility of the model simplification or substitution of its separate components for more effective components without interfering system functioning. The results of biometric identification system modeling and evaluating are presented and discussed.

Simulation of a Petri net-based model of the terpenoid biosynthesis pathway.

PubMed

Hawari, Aliah Hazmah; Mohamed-Hussein, Zeti-Azura

2010-02-09

The development and simulation of dynamic models of terpenoid biosynthesis has yielded a systems perspective that provides new insights into how the structure of this biochemical pathway affects compound synthesis. These insights may eventually help identify reactions that could be experimentally manipulated to amplify terpenoid production. In this study, a dynamic model of the terpenoid biosynthesis pathway was constructed based on the Hybrid Functional Petri Net (HFPN) technique. This technique is a fusion of three other extended Petri net techniques, namely Hybrid Petri Net (HPN), Dynamic Petri Net (HDN) and Functional Petri Net (FPN). The biological data needed to construct the terpenoid metabolic model were gathered from the literature and from biological databases. These data were used as building blocks to create an HFPNe model and to generate parameters that govern the global behaviour of the model. The dynamic model was simulated and validated against known experimental data obtained from extensive literature searches. The model successfully simulated metabolite concentration changes over time (pt) and the observations correlated with known data. Interactions between the intermediates that affect the production of terpenes could be observed through the introduction of inhibitors that established feedback loops within and crosstalk between the pathways. Although this metabolic model is only preliminary, it will provide a platform for analysing various high-throughput data, and it should lead to a more holistic understanding of terpenoid biosynthesis.

Multi-variants synthesis of Petri nets for FPGA devices

NASA Astrophysics Data System (ADS)

Bukowiec, Arkadiusz; Doligalski, Michał

2015-09-01

There is presented new method of synthesis of application specific logic controllers for FPGA devices. The specification of control algorithm is made with use of control interpreted Petri net (PT type). It allows specifying parallel processes in easy way. The Petri net is decomposed into state-machine type subnets. In this case, each subnet represents one parallel process. For this purpose there are applied algorithms of coloring of Petri nets. There are presented two approaches of such decomposition: with doublers of macroplaces or with one global wait place. Next, subnets are implemented into two-level logic circuit of the controller. The levels of logic circuit are obtained as a result of its architectural decomposition. The first level combinational circuit is responsible for generation of next places and second level decoder is responsible for generation output symbols. There are worked out two variants of such circuits: with one shared operational memory or with many flexible distributed memories as a decoder. Variants of Petri net decomposition and structures of logic circuits can be combined together without any restrictions. It leads to existence of four variants of multi-variants synthesis.

On determining firing delay time of transitions for Petri net based signaling pathways by introducing stochastic decision rules.

PubMed

Miwa, Yoshimasa; Li, Chen; Ge, Qi-Wei; Matsuno, Hiroshi; Miyano, Satoru

2010-01-01

Parameter determination is important in modeling and simulating biological pathways including signaling pathways. Parameters are determined according to biological facts obtained from biological experiments and scientific publications. However, such reliable data describing detailed reactions are not reported in most cases. This prompted us to develop a general methodology of determining the parameters of a model in the case of that no information of the underlying biological facts is provided. In this study, we use the Petri net approach for modeling signaling pathways, and propose a method to determine firing delay times of transitions for Petri net models of signaling pathways by introducing stochastic decision rules. Petri net technology provides a powerful approach to modeling and simulating various concurrent systems, and recently have been widely accepted as a description method for biological pathways. Our method enables to determine the range of firing delay time which realizes smooth token flows in the Petri net model of a signaling pathway. The availability of this method has been confirmed by the results of an application to the interleukin-1 induced signaling pathway.

Applications of the Petri net to simulate, test, and validate the performance and safety of complex, heterogeneous, multi-modality patient monitoring alarm systems.

PubMed

Sloane, E B; Gelhot, V

2004-01-01

This research is motivated by the rapid pace of medical device and information system integration. Although the ability to interconnect many medical devices and information systems may help improve patient care, there is no way to detect if incompatibilities between one or more devices might cause critical events such as patient alarms to go unnoticed or cause one or more of the devices to become stuck in a disabled state. Petri net tools allow automated testing of all possible states and transitions between devices and/or systems to detect potential failure modes in advance. This paper describes an early research project to use Petri nets to simulate and validate a multi-modality central patient monitoring system. A free Petri net tool, HPSim, is used to simulate two wireless patient monitoring networks: one with 44 heart monitors and a central monitoring system and a second version that includes an additional 44 wireless pulse oximeters. In the latter Petri net simulation, a potentially dangerous heart arrhythmia and pulse oximetry alarms were detected.

Petri net modeling of high-order genetic systems using grammatical evolution.

PubMed

Moore, Jason H; Hahn, Lance W

2003-11-01

Understanding how DNA sequence variations impact human health through a hierarchy of biochemical and physiological systems is expected to improve the diagnosis, prevention, and treatment of common, complex human diseases. We have previously developed a hierarchical dynamic systems approach based on Petri nets for generating biochemical network models that are consistent with genetic models of disease susceptibility. This modeling approach uses an evolutionary computation approach called grammatical evolution as a search strategy for optimal Petri net models. We have previously demonstrated that this approach routinely identifies biochemical network models that are consistent with a variety of genetic models in which disease susceptibility is determined by nonlinear interactions between two DNA sequence variations. In the present study, we evaluate whether the Petri net approach is capable of identifying biochemical networks that are consistent with disease susceptibility due to higher order nonlinear interactions between three DNA sequence variations. The results indicate that our model-building approach is capable of routinely identifying good, but not perfect, Petri net models. Ideas for improving the algorithm for this high-dimensional problem are presented.

On determining firing delay time of transitions for petri net based signaling pathways by introducing stochastic decision rules.

PubMed

Miwa, Yoshimasa; Li, Chen; Ge, Qi-Wei; Matsuno, Hiroshi; Miyano, Satoru

2011-01-01

Parameter determination is important in modeling and simulating biological pathways including signaling pathways. Parameters are determined according to biological facts obtained from biological experiments and scientific publications. However, such reliable data describing detailed reactions are not reported in most cases. This prompted us to develop a general methodology of determining the parameters of a model in the case of that no information of the underlying biological facts is provided. In this study, we use the Petri net approach for modeling signaling pathways, and propose a method to determine firing delay times of transitions for Petri net models of signaling pathways by introducing stochastic decision rules. Petri net technology provides a powerful approach to modeling and simulating various concurrent systems, and recently have been widely accepted as a description method for biological pathways. Our method enables to determine the range of firing delay time which realizes smooth token flows in the Petri net model of a signaling pathway. The availability of this method has been confirmed by the results of an application to the interleukin-1 induced signaling pathway.

Reconstructing the regulatory network controlling commitment and sporulation in Physarum polycephalum based on hierarchical Petri Net modelling and simulation.

PubMed

Marwan, Wolfgang; Sujatha, Arumugam; Starostzik, Christine

2005-10-21

We reconstruct the regulatory network controlling commitment and sporulation of Physarum polycephalum from experimental results using a hierarchical Petri Net-based modelling and simulation framework. The stochastic Petri Net consistently describes the structure and simulates the dynamics of the molecular network as analysed by genetic, biochemical and physiological experiments within a single coherent model. The Petri Net then is extended to simulate time-resolved somatic complementation experiments performed by mixing the cytoplasms of mutants altered in the sporulation response, to systematically explore the network structure and to probe its dynamics. This reverse engineering approach presumably can be employed to explore other molecular or genetic signalling systems where the activity of genes or their products can be experimentally controlled in a time-resolved manner.

Learning Petri net models of non-linear gene interactions.

PubMed

Mayo, Michael

2005-10-01

Understanding how an individual's genetic make-up influences their risk of disease is a problem of paramount importance. Although machine-learning techniques are able to uncover the relationships between genotype and disease, the problem of automatically building the best biochemical model or "explanation" of the relationship has received less attention. In this paper, I describe a method based on random hill climbing that automatically builds Petri net models of non-linear (or multi-factorial) disease-causing gene-gene interactions. Petri nets are a suitable formalism for this problem, because they are used to model concurrent, dynamic processes analogous to biochemical reaction networks. I show that this method is routinely able to identify perfect Petri net models for three disease-causing gene-gene interactions recently reported in the literature.

Shallot Aphids, Myzus ascalonicus, in Strawberry: Biocontrol Potential of Three Predators and Three Parasitoids

PubMed Central

Enkegaard, Annie; Sigsgaard, Lene; Kristensen, Kristian

2013-01-01

The parasitization capacity of 3 parasitoids and the predation capacity of 3 predators towards the shallot aphid, Myzus ascalonicus Doncaster (Homoptera: Aphididae), on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae) cv. Honeoye, were examined in laboratory experiments. In Petri dish assays, both Aphidius colemani Viereck (Hymenoptera: Aphidiidae) and A. ervi Haliday readily stung shallot aphids, with no significant difference in stinging frequency between the two species. A. ervi induced a significantly higher mortality (79.0 ± 7.2%) in terms of stung aphids compared with A. colemani (55.3 ± 4.1%); however, only a minor fraction (2.7 ± 1.8% and 7.1 ± 3.1%, respectively) of the killed aphids resulted in formation of mummies, presumably due to a physiological response to parasitism. The low percentage of mummification precludes the use of either Aphidius species in anything but inundative biocontrol. In similar set-ups, Aphelinus abdominalis (Dalman) (Hymenoptera: Aphelinidae) killed almost half (49.6 ± 5.3%) of the exposed aphids through host feeding. In addition, 23.2 ± 7.3% of non-host-fed aphids developed into mummified aphids, and 38.1 ± 13.2% of non-host-fed aphids died from other parasitoid-induced causes. However, the host feeding rate was reduced to only 1.2 ± 0.8%, and no significant parasitization mortality was observed on strawberry plants, suggesting that host plants interfered with A. abdominalis activity. This parasitoid does not, therefore, seem to be suited to either inoculative or inundative biocontrol of shallot aphids in strawberry. The three predators studied were the green lacewing, Chrysoperla carnea Steph. (Neuroptera: Chrysopidae), the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae), and the gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). Third instars of all 3 predators readily preyed upon the shallot aphid in Petri dish set-ups with significant differences in daily predation (34.62 ± 3.45, 25.25 ± 3.18, and 13.34 ± 1.45, respectively). Further studies on A. bipunctata revealed that the larvae maintained their daily predation capacity (32.0 ± 6.3) on strawberry plants. About 60% of already ovipositing A. bipunctata refrained from laying any eggs on the first day after transfer to set-ups with combinations of shallot or peach-potato aphids, Myzus persicae (Sulzer) (Homoptera: Aphididae), and strawberry or sweet pepper leaves. The aphid species and the plant species did not, however, have a significant influence on the number of females laying eggs, the average number of eggs laid during the first day being 6.37±1.28 per female. Adult lady beetles had a significant preference for odor from controls without plants over odors from uninfested strawberry or pepper plants, but they showed no preference for either of the plant species, whether infested with aphids or not. The predation capacity of A. bipunctata on shallot aphids holds promise for its use in inundative biocontrol, and the results on egg laying cues suggests that inoculative biocontrol may be possible, although further studies will be needed for a complete evaluation. PMID:24224712

Rigid collapsible dish structure

NASA Technical Reports Server (NTRS)

Palmer, William B. (Inventor); Giebler, Martin M. (Inventor)

1982-01-01

A collapsible dish structure composed of a plurality of rows of rigid radial petal assemblies concentric with the axis of the dish. The petal assemblies consist of a center petal and two side petals, the center petal hinged on an axis tangent to a circle concentric with the axis of the dish and the side petals hinged to the center petal at their mating edge. The center petal is foldable inwardly and the side petals rotate about their hinges such that the collapsed dish structure occupies a much smaller volume than the deployed dish. Means of controlling the shape of the dish to compensate for differential expansion of the deployed dish are also provided.

Modified Petri net model sensitivity to workload manipulations

NASA Technical Reports Server (NTRS)

White, S. A.; Mackinnon, D. P.; Lyman, J.

1986-01-01

Modified Petri Nets (MPNs) are investigated as a workload modeling tool. The results of an exploratory study of the sensitivity of MPNs to work load manipulations in a dual task are described. Petri nets have been used to represent systems with asynchronous, concurrent and parallel activities (Peterson, 1981). These characteristics led some researchers to suggest the use of Petri nets in workload modeling where concurrent and parallel activities are common. Petri nets are represented by places and transitions. In the workload application, places represent operator activities and transitions represent events. MPNs have been used to formally represent task events and activities of a human operator in a man-machine system. Some descriptive applications demonstrate the usefulness of MPNs in the formal representation of systems. It is the general hypothesis herein that in addition to descriptive applications, MPNs may be useful for workload estimation and prediction. The results are reported of the first of a series of experiments designed to develop and test a MPN system of workload estimation and prediction. This first experiment is a screening test of MPN model general sensitivity to changes in workload. Positive results from this experiment will justify the more complicated analyses and techniques necessary for developing a workload prediction system.

An analysis of the Petri net based model of the human body iron homeostasis process.

PubMed

Sackmann, Andrea; Formanowicz, Dorota; Formanowicz, Piotr; Koch, Ina; Blazewicz, Jacek

2007-02-01

In the paper a Petri net based model of the human body iron homeostasis is presented and analyzed. The body iron homeostasis is an important but not fully understood complex process. The modeling of the process presented in the paper is expressed in the language of Petri net theory. An application of this theory to the description of biological processes allows for very precise analysis of the resulting models. Here, such an analysis of the body iron homeostasis model from a mathematical point of view is given.

An object-oriented description method of EPMM process

NASA Astrophysics Data System (ADS)

Jiang, Zuo; Yang, Fan

2017-06-01

In order to use the object-oriented mature tools and language in software process model, make the software process model more accord with the industrial standard, it’s necessary to study the object-oriented modelling of software process. Based on the formal process definition in EPMM, considering the characteristics that Petri net is mainly formal modelling tool and combining the Petri net modelling with the object-oriented modelling idea, this paper provides this implementation method to convert EPMM based on Petri net into object models based on object-oriented description.

Neural system modeling and simulation using Hybrid Functional Petri Net.

PubMed

Tang, Yin; Wang, Fei

2012-02-01

The Petri net formalism has been proved to be powerful in biological modeling. It not only boasts of a most intuitive graphical presentation but also combines the methods of classical systems biology with the discrete modeling technique. Hybrid Functional Petri Net (HFPN) was proposed specially for biological system modeling. An array of well-constructed biological models using HFPN yielded very interesting results. In this paper, we propose a method to represent neural system behavior, where biochemistry and electrical chemistry are both included using the Petri net formalism. We built a model for the adrenergic system using HFPN and employed quantitative analysis. Our simulation results match the biological data well, showing that the model is very effective. Predictions made on our model further manifest the modeling power of HFPN and improve the understanding of the adrenergic system. The file of our model and more results with their analysis are available in our supplementary material.

Embryos of a moss can be hardened to desiccation tolerance: effects of rate of drying on the timeline of recovery and dehardening in Aloina ambigua (Pottiaceae).

PubMed

Brinda, John C; Stark, Lloyd R; Clark, Theresa A; Greenwood, Joshua L

2016-01-01

Embryonic sporophytes of the moss Aloina ambigua are inducibly desiccation tolerant (DT). Hardening to DT describes a condition of temporary tolerance to a rapid-drying event conferred by a previous slow-drying event. This paper aimed to determine whether sporophytic embryos of a moss can be hardened to DT, to assess how the rate of desiccation influences the post-rehydration dynamics of recovery, hardening and dehardening, and to determine the minimum rate of drying for embryos and shoots. Embryos were exposed to a range of drying rates using wetted filter paper in enclosed Petri dishes, monitoring relative humidity (RH) inside the dish and equilibrating tissues with 50% RH. Rehydrated embryos and shoots were subjected to a rapid-drying event at intervals, allowing assessments of recovery, hardening and dehardening times. The minimum rate of slow drying for embryonic survival was ∼3·5 h and for shoots ∼9 h. Hardening to DT was dependent upon the prior rate of drying. When the rate of drying was extended to 22 h, embryonic hardening was strong (>50% survival) with survival directly proportional to the post-rehydration interval preceding rapid drying. The recovery time (repair/reassembly) was so short as to be undetectable in embryos and shoots desiccated gradually; however, embryos dried in <3·5 h exhibited a lag time in development of ∼4 d, consistent with recovery. Dehardening resulted in embryos incapable of surviving a rapid-drying event. The ability of moss embryos to harden to DT and the influence of prior rate of drying on the dynamics of hardening are shown for the first time. The minimum rate of drying is introduced as a new metric for assessing ecological DT, defined as the minimum duration at sub-turgor during a drying event in which upon rehydration the plant organ of interest survives relatively undamaged from the desiccating event. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Embryos of a moss can be hardened to desiccation tolerance: effects of rate of drying on the timeline of recovery and dehardening in Aloina ambigua (Pottiaceae)

PubMed Central

Brinda, John C.; Stark, Lloyd R.; Clark, Theresa A.; Greenwood, Joshua L.

2016-01-01

Background and Aims Embryonic sporophytes of the moss Aloina ambigua are inducibly desiccation tolerant (DT). Hardening to DT describes a condition of temporary tolerance to a rapid-drying event conferred by a previous slow-drying event. This paper aimed to determine whether sporophytic embryos of a moss can be hardened to DT, to assess how the rate of desiccation influences the post-rehydration dynamics of recovery, hardening and dehardening, and to determine the minimum rate of drying for embryos and shoots. Methods Embryos were exposed to a range of drying rates using wetted filter paper in enclosed Petri dishes, monitoring relative humidity (RH) inside the dish and equilibrating tissues with 50 % RH. Rehydrated embryos and shoots were subjected to a rapid-drying event at intervals, allowing assessments of recovery, hardening and dehardening times. Key Results The minimum rate of slow drying for embryonic survival was ∼3·5 h and for shoots ∼9 h. Hardening to DT was dependent upon the prior rate of drying. When the rate of drying was extended to 22 h, embryonic hardening was strong (>50 % survival) with survival directly proportional to the post-rehydration interval preceding rapid drying. The recovery time (repair/reassembly) was so short as to be undetectable in embryos and shoots desiccated gradually; however, embryos dried in <3·5 h exhibited a lag time in development of ∼4 d, consistent with recovery. Dehardening resulted in embryos incapable of surviving a rapid-drying event. Conclusions The ability of moss embryos to harden to DT and the influence of prior rate of drying on the dynamics of hardening are shown for the first time. The minimum rate of drying is introduced as a new metric for assessing ecological DT, defined as the minimum duration at sub-turgor during a drying event in which upon rehydration the plant organ of interest survives relatively undamaged from the desiccating event. PMID:26354931

Diffuse idiopathic skeletal hyperostosis association with thoracic spine kyphosis: a cross-sectional study for the Health Aging and Body Composition Study.

PubMed

Nardo, Lorenzo; Lane, Nancy E; Parimi, Neeta; Cawthon, Peggy M; Fan, Bo; Shepherd, John; Cauley, Jane; Zucker-Levin, Audrey; Murphy, Rachel A; Katzman, Wendy B

2014-11-15

A descriptive study of the association between diffuse idiopathic skeletal hyperostosis (DISH) and kyphosis. To investigate the association of DISH with Cobb angle of kyphosis in a large cohort of older subjects from the Health Aging and Body Composition Study. DISH and thoracic kyphosis are well-defined radiographical findings in spines of older individuals. Characteristics of DISH (ossifications between vertebral segments) reflect changes of spine anatomy and physiology that may be associated with Cobb angle of kyphosis. Using data from 1172 subjects aged 70 to 79 years, we measured DISH and Cobb angle of kyphosis from computed tomographic lateral scout scans. Characteristics of participants with and without DISH were assessed using the χ² and t tests. Association between DISH and Cobb angle was analyzed using linear regression. Cobb angle and DISH relationship was assessed at different spine levels (thoracic and lumbar). DISH was identified on computed tomographic scout scan in 152 subjects with 101 cases in only the thoracic spine and 51 in both thoracic and lumbar spine segments. The mean Cobb angle of kyphosis in the analytic sample was 31.3° (standard deviation = 11.2). The presence of DISH was associated with a greater Cobb angle of 9.1° and 95% confidence interval (95% CI) (5.6-12.6) among African Americans and a Cobb angle of 2.9° and 95% CI (0.5-5.2) among Caucasians compared with those with no DISH. DISH in the thoracic spine alone was associated with a greater Cobb angle of 10.6° and 95% CI (6.5-14.7) in African Americans and a Cobb angle of 3.8° and 95% CI (1.0-6.5) in Caucasians compared with those with no DISH. DISH is associated with greater Cobb angle of kyphosis, especially when present in the thoracic spine alone. The association of DISH with Cobb angle is stronger within the African American population.

Fluid Stochastic Petri Nets: Theory, Applications, and Solution

NASA Technical Reports Server (NTRS)

Horton, Graham; Kulkarni, Vidyadhar G.; Nicol, David M.; Trivedi, Kishor S.

1996-01-01

In this paper we introduce a new class of stochastic Petri nets in which one or more places can hold fluid rather than discrete tokens. We define a class of fluid stochastic Petri nets in such a way that the discrete and continuous portions may affect each other. Following this definition we provide equations for their transient and steady-state behavior. We present several examples showing the utility of the construct in communication network modeling and reliability analysis, and discuss important special cases. We then discuss numerical methods for computing the transient behavior of such nets. Finally, some numerical examples are presented.

Necessary and sufficient liveness condition of GS3PR Petri nets

NASA Astrophysics Data System (ADS)

Liu, GaiYun; Barkaoui, Kamel

2015-05-01

Structural analysis is one of the most important and efficient methods to investigate the behaviour of Petri nets. Liveness is a significant behavioural property of Petri nets. Siphons, as structural objects of a Petri net, are closely related to its liveness. Many deadlock control policies for flexible manufacturing systems (FMS) modelled by Petri nets are implemented via siphon control. Most of the existing methods design liveness-enforcing supervisors by adding control places for siphons based on their controllability conditions. To compute a liveness-enforcing supervisor with as much as permissive behaviour, it is both theoretically and practically significant to find an exact controllability condition for siphons. However, the existing conditions, max, max‧, and max″-controllability of siphons are all overly restrictive and generally sufficient only. This paper develops a new condition called max*-controllability of the siphons in generalised systems of simple sequential processes with resources (GS3PR), which are a net subclass that can model many real-world automated manufacturing systems. We show that a GS3PR is live if all its strict minimal siphons (SMS) are max*-controlled. Compared with the existing conditions, i.e., max-, max‧-, and max″-controllability of siphons, max*-controllability of the SMS is not only sufficient but also necessary. An example is used to illustrate the proposed method.

The Coupling of Related Demonstrations to Illustrate Principles in Chemical Kinetics and Equilibrium

NASA Astrophysics Data System (ADS)

Pacer, Richard A.

1997-05-01

Two very simple lecture demonstrations, both involving the reaction of magnesium with one or more dilute acids, are linked together to illustrate principles in chemical kinetics and equilibrium. In the first, crumpled Mg ribbon is placed in the nipple of a baby bottle holding 200 mL of 0.40 M HCl. The bottle is inverted into a large beaker of water, and the volume of H2 gas generated in one minute is measured. the experiment is repeated with 0.60 M HCl. The rate law, Rate = k[H+]n, is developed from the data. In the second, equal lengths of Mg ribbon are placed in small beakers or Petri dishes, on an overhead projector, containing equal (0.80 to 1.0 M) concentrations of HCl, H3BO3, and CH3CO2H. Acids are not identified; students are merely told that 'Acids A, B, and C are of the same molarity.' Students are then asked to explain why the rates are so different, which serves as a lead-in for the instructor to explain the meaning of a Ka value. Students readily conclude that one of the acids must be a strong acid, but are puzzled by the other two. [The enormous difference in the Ka values of acetic and boric acids results in a striking difference in their reaction rates.

A microfluidic platform for 3-dimensional cell culture and cell-based assays.

PubMed

Kim, Minseok S; Yeon, Ju Hun; Park, Je-Kyun

2007-02-01

This paper reports a novel microfluidic platform introducing peptide hydrogel to make biocompatible microenvironment as well as realizing in situ cell-based assays. Collagen composite, OPLA and Puramatrix scaffolds are compared to select good environment for human hepatocellular carcinoma cells (HepG2) by albumin measurement. The selected biocompatible self-assembling peptide hydrogel, Puramatrix, is hydrodynamically focused in the middle of main channel of a microfluidic device, and at the same time the cells are 3-dimensionally immobilized and encapsulated without any additional surface treatment. HepG2 cells have been 3-dimensionally cultured in a poly(dimethylsiloxane) (PDMS) microfluidic device for 4 days. The cells cultured in micro peptide scaffold are compared with those cultured by conventional petri dish in morphology and the rate of albumin secretion. By injection of different reagents into either side of the peptide scaffold, the microfluidic device also forms a linear concentration gradient profile across the peptide scaffold due to molecular diffusion. Based on this characteristic, toxicity tests are performed by Triton X-100. As the higher toxicant concentration gradient forms, the wider dead zone of cells in the peptide scaffold represents. This microfluidic platform facilitates in vivo-like 3-dimensional microenvironment, and have a potential for the applications of reliable cell-based screening and assays including cytotoxicity test, real-time cell viability monitoring, and continuous dose-response assay.

Antimutagenicity of Methanolic Extracts from Anemopsis californica in Relation to Their Antioxidant Activity

PubMed Central

Del-Toro-Sánchez, Carmen Lizette; Bautista-Bautista, Nereyda; Blasco-Cabal, José Luis; Gonzalez-Ávila, Marisela; Gutiérrez-Lomelí, Melesio; Arriaga-Alba, Myriam

2014-01-01

Anemopsis californica has been used empirically to treat infectious diseases. However, there are no antimutagenic evaluation reports on this plant. The present study evaluated the antioxidant activity in relation to the mutagenic and antimutagenic activity properties of leaf (LME) and stem (SME) methanolic extracts of A. californica collected in the central Mexican state of Querétaro. Antioxidant properties and total phenols of extracts were evaluated using DPPH (1,1-diphenyl-2-picrylhydrazyl) and Folin-Ciocalteu methods, respectively. Mutagenicity was evaluated using the Ames test employing Salmonella enterica serovar Typhimurium strains (TA98, TA100, and TA102), with and without an aroclor 1254 (S9 mixture). Antimutagenesis was performed against mutations induced on the Ames test with MNNG, 2AA, or 4NQO. SME presented the highest antioxidant capacity and total phenolic content. None of the extracts exhibited mutagenicity in the Ames test. The extracts produced a significant reduction in 2AA-induced mutations in S. typhimurium TA98. In both extracts, mutagenesis induced by 4NQO or methyl-N′-nitro-N-nitrosoguanidine (MNNG) was reduced only if the exposure of strains was <10 μg/Petri dish. A. californca antioxidant properties and its capacity to reduce point mutations render it suitable to enhance medical cancer treatments. The significant effect against antimutagenic 2AA suggests that their consumption would provide protection against carcinogenic polycyclic aromatic compounds. PMID:25152760

Integration of Multiple Components in Polystyrene-based Microfluidic Devices Part 1: Fabrication and Characterization

PubMed Central

Johnson, Alicia S.; Anderson, Kari B.; Halpin, Stephen T.; Kirkpatrick, Douglas C.; Spence, Dana M.; Martin, R. Scott

2012-01-01

In Part I of a two-part series, we describe a simple, and inexpensive approach to fabricate polystyrene devices that is based upon melting polystyrene (from either a Petri dish or powder form) against PDMS molds or around electrode materials. The ability to incorporate microchannels in polystyrene and integrate the resulting device with standard laboratory equipment such as an optical plate reader for analyte readout and micropipettors for fluid propulsion is first described. A simple approach for sample and reagent delivery to the device channels using a standard, multi-channel micropipette and a PDMS-based injection block is detailed. Integration of the microfluidic device with these off-chip functions (sample delivery and readout) enables high throughput screens and analyses. An approach to fabricate polystyrene-based devices with embedded electrodes is also demonstrated, thereby enabling the integration of microchip electrophoresis with electrochemical detection through the use of a palladium electrode (for a decoupler) and carbon-fiber bundle (for detection). The device was sealed against a PDMS-based microchannel and used for the electrophoretic separation and amperometric detection of dopamine, epinephrine, catechol, and 3,4-dihydroxyphenylacetic acid. Finally, these devices were compared against PDMS-based microchips in terms of their optical transparency and absorption of an anti-platelet drug, clopidogrel. Part I of this series lays the foundation for Part II, where these devices were utilized for various on-chip cellular analysis. PMID:23120747

Facile transfer of thickness controllable poly(methyl methacrylate) patterns on a nanometer scale onto SiO2 substrates via microcontact printing combined with simplified Langmuir-Schaefer technique.

PubMed

Kim, Yong-Kwan; Kim, Dae-Il; Park, Jaehyun; Shin, Gunchul; Kim, Gyu Tae; Ha, Jeong Sook

2008-12-16

We report on the facile patterning of poly(methyl methacrylate) (PMMA) layers onto SiO2 substrates via microcontact printing combined with the simplified Langmuir-Schaefer (LS) technique. Langmuir film of PMMA was formed just by dropping a dilute PMMA solution onto the air/water surface in a glass Petri dish via self-assembly, and it was used as an ink for the patterned poly(dimethylsilioxane) (PDMS) stamp. The transferred film properties were systematically investigated with variation of postannealing temperature, molecular weight of PMMA, and the inking number. The patterned PMMA film surface was smooth with no vacancy defect in a few micrometers scale AFM images over the whole film area after post-annealing process. The thickness of the PMMA patterns was controlled on the nanometer scale by the number of inkings of the LS layer of PMMA on the PDMS stamp. By using the PMMA patterns as a barrier and a sacrificial layer against the chemical etching and metal deposition, SiO2 and metal patterns were fabricated, respectively. The PMMA layers also worked as a passivation layer against the patterning of V2O5 nanowires and the selective adsorption of single-walled carbon nanotubes (SWCNTs). We also fabricated thin film transistors using patterned SWCNTs with different percolation states and investigated the electrical properties.

Free-living spirochetes from Cape Cod microbial mats detected by electron microscopy

NASA Technical Reports Server (NTRS)

Teal, T. H.; Chapman, M.; Guillemette, T.; Margulis, L.

1996-01-01

Spirochetes from microbial mats and anaerobic mud samples collected in salt marshes were studied by light microscopy, whole mount and thin section transmission electron microscopy. Enriched in cellobiose-rifampin medium, selective for Spirochaeta bajacaliforniensis, seven distinguishable spirochete morphotypes were observed. Their diameters ranged from 0.17 micron to > 0.45 micron. Six of these morphotypes came from southwest Cape Cod, Massachusetts: five from Microcoleus-dominated mat samples collected at Sippewissett salt marsh and one from anoxic mud collected at School Street salt marsh (on the east side of Eel Pond). The seventh morphotype was enriched from anoxic mud sampled from the north central Cape Cod, at the Sandy Neck salt marsh. Five of these morphotypes are similar or identical to previously described spirochetes (Leptospira, Spirochaeta halophila, Spirochaeta bajacaliforniensis, Spirosymplokos deltaeiberi and Treponema), whereas the other two have unique features that suggest they have not been previously described. One of the morphotypes resembles Spirosymplokos deltaeiberi (the largest free-living spirochete described), in its large variable diameter (0.4-3.0 microns), cytoplasmic granules, and spherical (round) bodies with composite structure. This resemblance permits its tentative identification as a Sippewissett strain of Spirosymplokos deltaeiberi. Microbial mats samples collected in sterile Petri dishes and stored dry for more than four years yielded many organisms upon rewetting, including small unidentified spirochetes in at least 4 out of 100 enrichments.

Trace element and major ion composition of wet and dry depositon in Ankara, Turkey

NASA Astrophysics Data System (ADS)

Kaya, Güven; Tuncel, Gürdal

Daily, wet-only precipitation samples collected over a two year period were analyzed for SO 42-, NO 3-, Cl -, NH 4+, H +, Ca, Mg, K, Na, Al, Cu, Cd, Cr, Zn, V and Ni. Weekly dry-deposition samples collected on petri-dishes over the same period were analyzed only for major ions. Concentrations of ions and elements in Ankara precipitation are comparable with concentrations reported in literature for other urban areas. However, the wet deposition fluxes are the lowest among literature values, owing to small annual precipitation in the region. Although, annual average pH in precipitation is 4.7, episodic rain events with fairly low pH's were observed. Approximately half of the acidity in Ankara precipitation is neutralized in the winter season, while the acidity is completely neutralized by airborne soil particles that are rich in CaCO 3 in the summer precipitation. The SO 42- and NO 3- contributes approximately equally on the free acidity in winter. Main forms of SO 42- and NO 3- in precipitation are CaSO 4 and Ca(NO 3) 2, respectively. Crustal elements and ions have higher concentrations during summer season, while anthropogenic ions and elements did not show well-defined seasonal cycles. The lack of industrial activity in Ankara has profound influence on the temporal behavior of elements and ions.

The presence of quill mites (Gabucinia bicaudata) and lice (Struthiolipeurus struthionis) in ostrich wing feathers.

PubMed

Cooper, R G; El Doumani, H A A

2006-03-01

Quill mites (Gabucinia bicaudata) and lice (Struthiolipeurus struthionis) may infest ostrich feathers, resulting in skin damage, pruritus and excessive feather preening and loss. Four different feather types (prime white, femina extra wide, femina class 1, and femina short; n = 10) were collected. The quill mites and lice were removed with fine forceps, studied using a photographic optical microscope and counted microscopically at x 100 magnification following collection by sedimentation. They were placed in separate Petri dishes containing lactophenol solution and examined (x40 magnification). Anatomical features are described. The density of quill mites in all feather types of both wings was higher than that of the lice. There was no significant difference between the counts of both arthropods on the left wing and the right wing, respectively, except for the femina class 1 quill mites (P = 0.01). The femina extra wide feathers were a preferred habitat in both wings. Large standard deviations (quill mites left wing: 73 +/- 8; quill mites right wing: 69 +/- 7) suggested variations in the degree of migration between feather shafts or as a response to escape preening. It is recommended that ostriches be treated with an oral preparation of Ivermectin administered per os at a dosage rate of 0.2 mg/kg at 30-day intervals for quill mites, and with a 1-5 % Malathion dust at 14-day intervals for lice.

A vacuum-actuated microtissue stretcher for long-term exposure to oscillatory strain within a 3D matrix.

PubMed

Walker, Matthew; Godin, Michel; Pelling, Andrew E

2018-05-28

Although our understanding of cellular behavior in response to extracellular biological and mechanical stimuli has greatly advanced using conventional 2D cell culture methods, these techniques lack physiological relevance. To a cell, the extracellular environment of a 2D plastic petri dish is artificially flat, extremely rigid, static and void of matrix protein. In contrast, we developed the microtissue vacuum-actuated stretcher (MVAS) to probe cellular behavior within a 3D multicellular environment composed of innate matrix protein, and in response to continuous uniaxial stretch. An array format, compatibility with live imaging and high-throughput fabrication techniques make the MVAS highly suited for biomedical research and pharmaceutical discovery. We validated our approach by characterizing the bulk microtissue strain, the microtissue strain field and single cell strain, and by assessing F-actin expression in response to chronic cyclic strain of 10%. The MVAS was shown to be capable of delivering reproducible dynamic bulk strain amplitudes up to 13%. The strain at the single cell level was found to be 10.4% less than the microtissue axial strain due to cellular rotation. Chronic cyclic strain produced a 35% increase in F-actin expression consistent with cytoskeletal reinforcement previously observed in 2D cell culture. The MVAS may further our understanding of the reciprocity shared between cells and their environment, which is critical to meaningful biomedical research and successful therapeutic approaches.

Functional cream cheese supplemented with Bifidobacterium animalis subsp. lactis DSM 10140 and Lactobacillus reuteri DSM 20016 and prebiotics.

PubMed

Speranza, Barbara; Campaniello, Daniela; Monacis, Noemi; Bevilacqua, Antonio; Sinigaglia, Milena; Corbo, Maria Rosaria

2018-06-01

The aim of this study was to develop a functional fresh cream cheese with Bifidobacterium animalis subsp. lactis DSM 10140 or Lactobacillus reuteri DSM 20016 and prebiotics (inulin, FOS and lactulose). The research was divided into two steps: in vitro evaluation of the effects of prebiotic compounds; validation at laboratory level with production of functional cream mini-cheeses. Prebiotics showed a protective effect: B. animalis subsp. lactis DSM 10140 cultivability on Petri dishes was positively influenced by lactulose, whereas fructooligosaccharides (FOS) were the prebiotic compounds able to prolong Lb. reuteri DSM 20016 cultivability. At 30 °C, a prolongation of the death time (more than 300 days) was observed, while the controls showed death time values about 100 days. At 45 °C, death time values increased from 32.2 (control) to 33, 35, and 38 days in the samples added with FOS, inulin and lactulose, respectively. Lactulose and FOS were chosen to be added to cream mini-cheeses inoculated with B. animalis subsp. lactis DSM 10140 and Lb. reuteri DSM 20016, respectively; the proposed functional cream cheese resulted in a product with favourable conditions for the viability of both probiotics which maintained cultivable cells above the recommended level during 28 days of storage at 4 °C with good sensory characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trichocomaceae: biodiversity of Aspergillus spp and Penicillium spp residing in libraries.

PubMed

Leite, Diniz Pereira; Yamamoto, Ana Caroline Akeme; Amadio, Janaína Vasconcellos Ribeiro de Souza; Martins, Evelin Rodrigues; do Santos, Fábio Alexandre Leal; Simões, Sara de Almeida Alves; Hahn, Rosane Christine

2012-10-19

Atmospheric air is the most common vehicle for the dispersion of fungi. Fungi belonging to the genera Aspergillus and Penicillium are cosmopolitan and are classified in the family Trichocomaceae. Species of the genera are commonly found in soil, decaying organic materials, animal feed, stored grains, and other materials. This study aimed to determine the taxonomic diversity of airborne fungi of the genera Aspergillus and Penicillium residing in the dust of library environments to contribute to current knowledge of these characteristic genera. Three libraries in the city of Cuiaba, State of Mato Grosso, Brazil, were selected as the study areas. A total of 168 samples were collected at randomized sites within each library in areas containing journals, archives, in study rooms, and in collection storage areas in two different periods, the dry season (n = 42)  and the rainy season (n = 42). Samples were collected by exposing Petri dishes containing Sabouraud agar with chloramphenicol to the environmental air. Additional samples were collected with sterile swabs which were rubbed over the surface of randomly chosen books on the shelves; the swabs were subsequently incubated in the laboratory. The genus Aspergillus was highlighted as one of the principal airborne fungi present in indoor environments. Aspergillus spp was identified in 1,277 (89.6%) samples and Penicillium spp in 148 (10.4%). The dry period exhibited a greater number of isolates of the two taxons.

Comparison of suction device with saliva ejector for aerosol and spatter reduction during ultrasonic scaling.

PubMed

Holloman, Jessica L; Mauriello, Sally M; Pimenta, Luiz; Arnold, Roland R

2015-01-01

Aerosols and spatter are concerns in health care owing to their potential adverse health effects. The Isolite illuminated isolation system (Isolite Systems) and a saliva ejector were compared for aerosol and spatter reduction during and after ultrasonic scaling. Fifty participants were randomized to control (n = 25, saliva ejector) or test (n = 25, Isolite) groups and received a prophylaxis with an ultrasonic scaler. Aerosols were collected in a petri dish containing transport media, dispersed, and plated to anaerobic blood agar to determine colony-forming units (CFUs). The authors analyzed the data using a t test. No significant difference occurred between groups in aerosol and spatter reduction (P = .25). Mean (standard deviation) of log10 CFUs per milliliter collected during ultrasonic scaling in the control and test groups were 3.61 (0.95) and 3.30 (0.88), respectively. All samples contained α-hemolytic streptococci, and many samples contained strictly oral anaerobes. A significant amount of contamination occurred during ultrasonic scaling in both groups, as indicated by high numbers of CFUs and the identification of strictly oral anaerobes in all plates. Neither device reduced aerosols and spatter effectively, and there was no significant difference in reduction between the 2 devices. Additional measures should be taken with these devices to reduce the likelihood of disease transmission. Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

Aquaporin genes GintAQPF1 and GintAQPF2 from Glomus intraradices contribute to plant drought tolerance.

PubMed

Li, Tao; Hu, Ya-Jun; Hao, Zhi-Peng; Li, Hong; Chen, Bao-Dong

2013-05-01

Arbuscular mycorrhizal (AM) symbiosis, established between AM fungi (AMF) and roots of higher plants, occurs in most terrestrial ecosystems. It has been well demonstrated that AM symbiosis can improve plant performance under various environmental stresses, including drought stress. However, the molecular basis for the direct involvement of AMF in plant drought tolerance has not yet been established. Most recently, we cloned two functional aquaporin genes, GintAQPF1 and GintAQPF2, from AM fungus Glomus intraradices. By heterologous gene expression in yeast, aquaporin localization, activities and water permeability were examined. Gene expressions during symbiosis in expose to drought stress were also analyzed. Our data strongly supported potential water transport via AMF to host plants. As a complement, here we adopted the monoxenic culture system for AMF, in which carrot roots transformed by Ri-T DNA were cultured with Glomus intraradices in two-compartment Petri dishes, to verify the aquaporin gene functions in assisting AMF survival under polyethylene glycol (PEG) treatment. Our results showed that 25% PEG significantly upregulated the expression of two aquaporin genes, which was in line with the gene functions examined in yeast. We therefore concluded that the aquaporins function similarly in AMF as in yeast subjected to osmotic stress. The study provided further evidence to the direct involvement of AMF in improving plant water relations under drought stresses.

Dark septate endophyte decreases stress on rice plants.

PubMed

Santos, Silvana Gomes Dos; Silva, Paula Renata Alves da; Garcia, Andres Calderin; Zilli, Jerri Édson; Berbara, Ricardo Luis Louro

Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Metabolites Identified during Varied Doses of Aspergillus Species in Zea mays Grains, and Their Correlation with Aflatoxin Levels

PubMed Central

Chrysanthopoulos, Panagiotis K.; Hodson, Mark P.; Darnell, Ross; Korie, Sam

2018-01-01

Aflatoxin contamination is associated with the development of aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus on food grains. This study was aimed at investigating metabolites produced during fungal development on maize and their correlation with aflatoxin levels. Maize cobs were harvested at R3 (milk), R4 (dough), and R5 (dent) stages of maturity. Individual kernels were inoculated in petri dishes with four doses of fungal spores. Fungal colonisation, metabolite profile, and aflatoxin levels were examined. Grain colonisation decreased with kernel maturity: milk-, dough-, and dent-stage kernels by approximately 100%, 60%, and 30% respectively. Aflatoxin levels increased with dose at dough and dent stages. Polar metabolites including alanine, proline, serine, valine, inositol, iso-leucine, sucrose, fructose, trehalose, turanose, mannitol, glycerol, arabitol, inositol, myo-inositol, and some intermediates of the tricarboxylic acid cycle (TCA—also known as citric acid or Krebs cycle) were important for dose classification. Important non-polar metabolites included arachidic, palmitic, stearic, 3,4-xylylic, and margaric acids. Aflatoxin levels correlated with levels of several polar metabolites. The strongest positive and negative correlations were with arabitol (R = 0.48) and turanose and (R = −0.53), respectively. Several metabolites were interconnected with the TCA; interconnections of the metabolites with the TCA cycle varied depending upon the grain maturity. PMID:29735944

Metabolites Identified during Varied Doses of Aspergillus Species in Zea mays Grains, and Their Correlation with Aflatoxin Levels.

PubMed

Falade, Titilayo D O; Chrysanthopoulos, Panagiotis K; Hodson, Mark P; Sultanbawa, Yasmina; Fletcher, Mary; Darnell, Ross; Korie, Sam; Fox, Glen

2018-05-07

Aflatoxin contamination is associated with the development of aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus on food grains. This study was aimed at investigating metabolites produced during fungal development on maize and their correlation with aflatoxin levels. Maize cobs were harvested at R3 (milk), R4 (dough), and R5 (dent) stages of maturity. Individual kernels were inoculated in petri dishes with four doses of fungal spores. Fungal colonisation, metabolite profile, and aflatoxin levels were examined. Grain colonisation decreased with kernel maturity: milk-, dough-, and dent-stage kernels by approximately 100%, 60%, and 30% respectively. Aflatoxin levels increased with dose at dough and dent stages. Polar metabolites including alanine, proline, serine, valine, inositol, iso-leucine, sucrose, fructose, trehalose, turanose, mannitol, glycerol, arabitol, inositol, myo-inositol, and some intermediates of the tricarboxylic acid cycle (TCA—also known as citric acid or Krebs cycle) were important for dose classification. Important non-polar metabolites included arachidic, palmitic, stearic, 3,4-xylylic, and margaric acids. Aflatoxin levels correlated with levels of several polar metabolites. The strongest positive and negative correlations were with arabitol ( R = 0.48) and turanose and ( R = −0.53), respectively. Several metabolites were interconnected with the TCA; interconnections of the metabolites with the TCA cycle varied depending upon the grain maturity.

Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems.

PubMed

Zhao, Jiangsan; Bodner, Gernot; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A; Nakhforoosh, Alireza

2017-02-01

Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Application of Hanging Drop Technique for Kidney Tissue Culture.

PubMed

Wang, Shaohui; Wang, Ximing; Boone, Jasmine; Wie, Jin; Yip, Kay-Pong; Zhang, Jie; Wang, Lei; Liu, Ruisheng

2017-01-01

The hanging drop technique is a well-established method used in culture of animal tissues. However, this method has not been used in adult kidney tissue culture yet. This study was to explore the feasibility of using this technique for culturing adult kidney cortex to study the time course of RNA viability in the tubules and vasculature, as well as the tissue structural integrity. In each Petri dish with the plate covered with sterile buffer, a section of mouse renal cortex was cultured within a drop of DMEM culture medium on the inner surface of the lip facing downward. The tissue were then harvested at each specific time points for Real-time PCR analysis and histological studies. The results showed that the mRNA level of most Na+ related transporters and cotransporters were stably maintained within 6 hours in culture, and that the mRNA level of most receptors found in the vasculature and glomeruli were stably maintained for up to 9 days in culture. Paraffin sections of the cultured renal cortex indicated that the tubules began to lose tubular integrity after 6 hours, but the glomeruli and vasculatures were still recognizable up to 9 days in culture. We concluded that adult kidney tissue culture by hanging drop method can be used to study gene expressions in vasculature and glomeruli. © 2017 The Author(s). Published by S. Karger AG, Basel.

Development and validation of an automated unit for the extraction of radiocaesium from seawater.

PubMed

Bokor, Ilonka; Sdraulig, Sandra; Jenkinson, Peter; Madamperuma, Janaka; Martin, Paul

2016-01-01

An automated unit was developed for the in-situ extraction of radiocaesium ((137)Cs and (134)Cs) from large volumes of seawater to achieve very low detection limits. The unit was designed for monitoring of Australian ocean and coastal waters, including at ports visited by nuclear-powered warships. The unit is housed within a robust case, and is easily transported and operated. It contains four filter cartridges connected in series. The first two cartridges are used to remove any suspended material that may be present in the seawater, while the last two cartridges are coated with potassium copper hexacyanoferrate for caesium extraction. Once the extraction is completed the coated cartridges are ashed. The ash is transferred to a small petri dish for counting of (137)Cs and (134)Cs by high resolution gamma spectrometry for a minimum of 24 h. The extraction method was validated for the following criteria: selectivity, trueness, precision, linearity, limit of detection and traceability. The validation showed the unit to be fit for purpose with the method capable of achieving low detection limits required for environmental samples. The results for the environmental measurements in Australian seawater correlate well with those reported in the Worldwide Marine Radioactivity Study (WOMARS). The cost of preparation and running the system is low and waste generation is minimal. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Increase in recombination rate in Arabidopsis thaliana plants sharing gaseous environment with X-ray and UVC-irradiated plants depends on production of radicals.

PubMed

Zemp, Franz J; Sidler, Corinne; Kovalchuk, Igor

2012-07-01

X-ray and UVC are the two physical agents that damage DNA directly, with both agents capable of inducing double-strand breaks. Some of our recent work has demonstrated that local exposure to UVC results in a systemic increase in recombination frequency, suggesting that information about exposure can be passed from damaged to non-damaged tissue. Indeed, we recently showed that plants sharing the same enclosed environment with UVC-irradiated plants exhibit similar increase in homologous recombination frequency as irradiated plants. Here, we further tested whether yet another DNA-damaging agent, X-ray, is capable of increasing recombination rate (RR) in neighboring plants grown in a Petri dish. To test this, we grew plants exposed to X-ray or UVC irradiation in an enclosed environment next to non-exposed plants. We found that both X-ray and UVC-irradiated plants and neighboring plants exhibited comparable increases in the levels of strand breaks and the RR. We further showed that pre-exposure of plants to radical scavenger DMSO substantially alleviates the radiation-induced increase in RR and prevents formation of bystander signal. Our results suggest that the increase in RR in bystander plants can also be triggered by X-ray and that radicals may play some role in initiation or maintenance of this signal.

Increase in recombination rate in Arabidopsis thaliana plants sharing gaseous environment with X-ray and UVC-irradiated plants depends on production of radicals

PubMed Central

Zemp, Franz J.; Sidler, Corinne; Kovalchuk, Igor

2012-01-01

X-ray and UVC are the two physical agents that damage DNA directly, with both agents capable of inducing double-strand breaks. Some of our recent work has demonstrated that local exposure to UVC results in a systemic increase in recombination frequency, suggesting that information about exposure can be passed from damaged to non-damaged tissue. Indeed, we recently showed that plants sharing the same enclosed environment with UVC-irradiated plants exhibit similar increase in homologous recombination frequency as irradiated plants. Here, we further tested whether yet another DNA-damaging agent, X-ray, is capable of increasing recombination rate (RR) in neighboring plants grown in a Petri dish. To test this, we grew plants exposed to X-ray or UVC irradiation in an enclosed environment next to non-exposed plants. We found that both X-ray and UVC-irradiated plants and neighboring plants exhibited comparable increases in the levels of strand breaks and the RR. We further showed that pre-exposure of plants to radical scavenger DMSO substantially alleviates the radiation-induced increase in RR and prevents formation of bystander signal. Our results suggest that the increase in RR in bystander plants can also be triggered by X-ray and that radicals may play some role in initiation or maintenance of this signal. PMID:22751301

Dereplicating and spatial mapping of secondary metabolites from fungal cultures in situ

DOE PAGES

Kertesz, Vilmos; Van Berkel, Gary J.; Sica, Vincent P.; ...

2015-07-30

Ambient ionization techniques coupled to mass spectrometry have recently become prevalent in natural product research due to their ability to examine secondary metabolites in situ. Identifying, mapping, and monitoring secondary metabolites directly on an organism provides invaluable spatial and temporal details that are lost through traditional extraction processes. Most ambient ionization techniques do not collect mutually supportive data, such as chromatographic retention times and/or UV/VIS spectra, and this can limit the ability to identify certain metabolites, such as differentiating isomers. To overcome this, the droplet liquid microjunction surface sampling probe (droplet LMJ SSP) was coupled with UPLC PDA HRMS MS/MS,more » thus providing separation, retention times, and UV/VIS data used in traditional dereplication protocols. By capturing these mutually supportive data, the identity of secondary metabolites could be confidently and rapidly assigned in situ. Using the droplet LMJ SSP, a protocol was constructed to analyze the secondary metabolite profile of fungal cultures directly without any sample preparation. The results demonstrate that fungal cultures can be dereplicated from the Petri dish, thus identifying secondary metabolites, including isomers, and confirming them against reference standards. As a result, heat maps, similar to mass spectrometry imaging, can be used to ascertain the location and relative concentration of secondary metabolites directly on the surface and/or surroundings of a fungal culture.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watrous, Jeramie D.; Roach, Patrick J.; Alexandrov, Theodore

Integrating the governing chemistry with the genomics and phenotypes of microbial colonies has been a "holy grail" in microbiology. This work describes a highly sensitive, broadly applicable, and costeffective approach that allows metabolic profiling of live microbial colonies directly from a Petri dish without any sample preparation. Nanospray desorption electrospray ionization mass spectrometry (MS), combined with alignment of MS data and molecular networking, enabled monitoring of metabolite production from live microbial colonies from diverse bacterial genera, including Bacillus subtilis, Streptomyces coelicolor, Mycobacterium smegmatis, and Pseudomonas aeruginosa. This work demonstrates that, by using these tools to visualize small molecular changes withinmore » bacterial interactions, insights can be gained into bacterial developmental processes as a result of the improved organization of MS/MS data. To validate this experimental platform, metabolic profiling was performed on Pseudomonas sp. SH-C52, which protects sugar beet plants from infections by specific soil-borne fungi [R. Mendes et al. (2011) Science 332:1097–1100]. The antifungal effect of strain SHC52 was attributed to thanamycin, a predicted lipopeptide encoded by a nonribosomal peptide synthetase gene cluster. Our technology, in combination with our recently developed peptidogenomics strategy, enabled the detection and partial characterization of thanamycin and showed that it is amonochlorinated lipopeptide that belongs to the syringomycin family of antifungal agents. In conclusion, the platform presented here provides a significant advancement in our ability to understand the spatiotemporal dynamics of metabolite production in live microbial colonies and communities.« less

Lethal and sublethal effects of essential oil of Lippia sidoides (Verbenaceae) and monoterpenes on Chagas’ disease vector Rhodnius prolixus

PubMed Central

Figueiredo, Marcela B; Gomes, Geovany A; Santangelo, Jayme M; Pontes, Emerson G; Azambuja, Patricia; Garcia, Elói S; de Carvalho, Mário G

2016-01-01

The aim of this study was to identify the composition of the essential oil from leaves of Lippia sidoides (EOLS), a typical shrub commonly found in the dry northeast of Brazil, popularly known as “alecrim-pimenta”. Additionally, we investigated the nymphicidal, ovicidal, phagoinhibitory and excretion effects of EOLS, its major constituent thymol and its isomer carvacrol, on fourth instar nymphs and eggs of Rhodnius prolixus, the Chagas’ disease vector. The nymphicidal and ovicidal activity of thymol, carvacrol, and EOLS was assessed by tests using impregnated Petri dishes. The lethal concentration values (LC50) for EOLS, carvacrol, and thymol were 54.48, 32.98, and 9.38 mg/cm2, respectively. The ovicidal test showed that both carvacrol and thymol (50 mg/cm2) inhibited hatching (50% and 23.3%, respectively), while treatments with 10 mg/cm2 or 50 mg/cm2 EOLS did not affect the hatching rate at all (80% and 90%, respectively). We observed an anti-feeding effect in insects fed with blood containing natural products at the higher concentrations (100 µg/mL). Finally, excretion rate was affected by EOLS and carvacrol, but not by thymol. These findings offer novel insights into basic physiological processes that make the tested natural compounds interesting candidates for new types of insecticides. PMID:27878214

Behavioral effects of Splenda, Equal and sucrose: clues from planarians on sweeteners

PubMed Central

Ouyang, Kevin; Nayak, Sunil; Lee, Young; Kim, Erin; Wu, Michael; Tallarida, Christopher S.; Rawls, Scott M.

2016-01-01

Sweetened diets share commonalities with drugs of abuse, but studies comparing behavioral effects of different sweeteners are lacking. Common table sugar produces rewarding and withdrawal effects in planarians. We postulated that Splenda and Equal would produce similar responses and used a tetrad of behavioral assays to test this hypothesis. Acute exposure to a relatively high concentration (10%) of each sweetener produced stereotyped responses (C-shapes) and reduced motility, with Equal producing greater motor effects than sucrose or Splenda. In experiments testing for anxiogenic-like effects, planarians withdrawn from Splenda (1, 3%) or sucrose (1, 3%), but not Equal, and placed into a petri dish with dark and light compartments spent more time in the dark compared to water controls. In place conditioning experiments, both Splenda (0.01%) and sucrose (0.01%) produced an environmental preference shift. Maltodextrin (0.1%), a principal ingredient of Splenda and Equal, produced a significant preference shift. In contrast, sucralose, an indigestible polysaccharide contained in Splenda and Equal, was ineffective. Our data reveal that Splenda produces sucrose-like rewarding and withdrawal effects in planarians that may be dependent on maltodextrin and dextrose. The ineffectiveness of Equal may be due to the presence of aspartame, which is too water insoluble to test in our planarian assay, or to its bitter aftertaste that could mask any rewarding effects produce by maltodextrin or dextrose. PMID:27845240

[Effect on calcium carbonate morphology by a strain of rock actinomycete].

PubMed

Chu, Yue; Cao, Chengliang; Lian, Bin

2016-07-04

Microbes-induced mineralization is one of the hottest issues in the field of geomicrobiology. Strain DHS C013T isolated from the surfaces of rocks in the Karst region was used to investigate microbial influence on the formation of carbonate and its morphology in the metallogenic system consisting NaHCO3 and Ca(NO3)2·4H2O. Strain DHS C013T was inoculated into malt extract-glucose-yeast extract peptone (MGYP) liquid medium. After cultivation we put the fermented solution, supernatant, hypha pellets, sterile MGYP liquid medium and ultrapure water into the metallogenic system separately. Scanning electronic microscope was applied to observe the crystals at the bottom of the petri dishes. In the metallogenic system with ultrapure water, only standard calcite of rhombohedron was found. However, special morphology of CaCO3, such as dumbbelllike, spherulite and scaly cylindrical shapes, were found in the metallogenic system with actinomycetes, hyphae fragment and their cell metabolism products. These calcium carbonates of special morphology might be resulted from their nucleation on smaller hypha pellets, hyphae fragment or extracellular secretion. Actinomycetes can induce the formation of CaCO3, and the mycelium and metabolites have important effects on regulating and influencing CaCO3 morphology. Our data provide new evidence for further understanding of the biological mineralization mediated by actinomycete and its metabolic products.

Colonization dynamic of various crop residues by Fusarium graminearum monitored through real-time PCR measurements.

PubMed

Leplat, J; Heraud, C; Gautheron, E; Mangin, P; Falchetto, L; Steinberg, C

2016-11-01

To evaluate the effect of the type of crop residues on the colonization dynamic of Fusarium graminearum in soil. The ability of F. graminearum to survive in the presence of various crop residues was assessed on Petri dishes and in microcosms. These microcosms comprised soil that had or had not been previously disinfested with or without amendment with various crop residues. The colonization dynamic of F. graminearum was monitored through real-time PCR. Fusarium graminearum development was higher in disinfested soil than in non-disinfested one. The fungal growth was enhanced to various extents according to the type of crop residues, except for mustard residues which inhibited it. The biochemical and physical properties of the residues were likely to account for the differences in the survival of F. graminearum. Fusarium graminearum is a poor competitor in soil but it can use maize, wheat, and rape residues to ensure its survival. Conversely alfalfa, which is assimilated by micro-organisms very easily, avoids long-lasting survival of the fungus. And finally, mustard producing glucosinolates could be used as an intermediate crop to reduce the inoculum amount. This study is contributing to the knowledge about F. graminearum saprotophic abilities and proposes interesting paths to limit its survival in soil. © 2016 The Society for Applied Microbiology.

Laser biostimulation of articular cartilage: in vitro evaluation

NASA Astrophysics Data System (ADS)

Jia, Yali; Guo, Zhouyi; Yang, Xiaohong; Zeng, Chang-Chun

2004-07-01

In the orthopaedic field, the repair of ariticular cartilage is still a difficult problem, because of the physiological characters of cartilaginous tissues and chondrocytes. To find an effective method of stimulating their regeneration, this in vitro study focuses on the biostimulation of rabbit articular chondrocytes by low-power He-Ne laser. The articular chondrocytes isolated from the cartilage of the medial condyle of the femur of the rabbit were incubated in HamF12 medium. The second passage culture were spread on 24 petri dishes and were irradiated with laser at power density of 2 - 12 mW/cm2 for 6.5 minutes, corresponding to the energy density of 1-6 J/cm2. Laser treatment was performed three times at a 24-hour interval. After lasering, incubation was continued for 24 hours. Non-irradiated cells were kept under the same conditions as the irradiated ones. The cell proliferation activity was evaluated with a XTT colorimetric method. Irradiation of 4 - 6 J/cm2 revealed a considerably higher cell proliferation activity comparing to control cultures. Thereinto, the energy density of 4 and 5 J/cm2 remarkably increased cell growth (P<0.01). The present study showed that a particular laser irradiation stimulates articular chondrocytes proliferation. These findings might be clinically relevant, indicating that low-power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.

Microbial contamination of the environment after the irradiation of Er:YAG laser in infected root canals

NASA Astrophysics Data System (ADS)

Brugnera, Aldo, Jr.; Zanin, Fatima A. A.; Sampaio Moura, Marcelo; Heredia Seixas, Fabio; Rodrigues de Araujo Estrela, Cyntia; Estrela, Carlos; Djalma Pecora, Jesus

2003-06-01

The purpose of this study was to analyze the environment microbial contamination produced by Er:YAG laser irradiation in infected root canals. A total of 20 human anterior teeth were prepared, sterilized and, then, inoculated with a mixture of the following microorganisms: S. Aureus, E. Faecalis, P. Aeruginosa, B. Subtilis and C. Albicans. After the contamination period (28 days), the teeth were irrigated with sterile distilled water or 1% sodium hypochlorite and, then, irradiated with an Er:YAG laser with two different laser parameters: 52 mJ or 110 mJ output at the fiber tip. Eighteen Petri dishes with 20 ml of BHI Agar were used in the study. For each group, 3 plates with BHIA were used for the analysis of the microbial contamination of the environment during the activation of the laser in infected root canals. The plates were positioned in differing distances away from the irradiated tooth (plate 1 - distance of 15 cm, plate 2 - distance of 50 cm and plate 3 - distance of 3 meters). After the analysis of the results, it was observed that the larger microbial contamination occurred in Group 1 (teeth irrigated with sterile distilled water and irradiated with Er:YAG laser with 52 mJ output at the fiber tip), plate 1 (positioned 15 cm away from the irradiated tooth), with values greater than 30 Colony-Forming Units (CFU).

Liquefaction of coal by Polyporus versicolor and Poria monticola. Final report, 1 September 1984-31 August 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, M.S.

1986-01-01

Polyporus versicolor (ATCC 12679), obtained from the American Type Culture Collection, Rockville, MD, has been demonstrated to degrade leonardite, lignite, and subbituminous coals to a black liquid product which is called the bioextract. The process of solubilizing the coal has been termed liquification. Fungi were routinely maintained in both solid Sabouraud maltose agar (6%) and in Sabouraud maltose broth cultures. All cultures were incubated at 30/sup 0/C, 84 to 98% relative humidity, and pH = 5.8. All materials which came into contact with the fungi were sterilized before use. Experimental cultures were incubated as described for stock cultures. Cultures weremore » incubated for approximately 12 days to produce a mature fungal mat across a glass petri dish. Coal pieces (approximately 5 mm/sup 3/) were placed directly on the hyphal mat. Liquified coal (the bioextract) was removed from the top of the mycelium and/or coal pieces and either stored for analyses at 4/sup 0/C or else freeze-dried and stored dessicated at room temperature. The bioextract has been produced in sufficient quantity to permit various methods of analysis including high performance liquid chromatography, UV-visible spectrophotometry, titrimetry, electrophoresis, proton nmr spectroscopy, and calorimetry. The solubility of the bioextract in different solvents has also been determined. 6 refs., 26 figs., 3 tabs.« less

Method for in vitro screening of aquatic fungicides

USGS Publications Warehouse

Bailey, T.A.

1983-01-01

Methods were developed for in vitro screening of candidate aquatic fungicides for efficacy against Achlya fiagellata, A. racemosa, Saprolegnia hypogyna and S. megasperma. Agar plugs containing fungal hyphae, removed from the edge of actively growing colonies, were placed in the depressions of spot plates containing 1a??0, 10a??0 and 100 mg/I of the candidate compounds for 15 or 60 min. After exposure, the plugs were transferred on to filter papers (0a??45-A?m pore) in a holder, rinsed, and then placed on cornmeal agar medium in tri-petri dishes. The plates were checked for mycelial growth after 48, 96 and 168 h of incubation in a lighted (400-800 A?m) environmental control chamber at 20A?2A?C. Criteria for the acceptance or rejection of candidate aquatic fungicides for further study were based on the antifungal spectrum index (ASI) comparisons between respective compounds and malachite green after 48 h and the concentration level producing complete growth inhibition. Candidate compounds whose ASI was less than 50% that of malachite green after 48 h or did not inhibit growth at levels less than 100 mg/l were rejected. This method provides a base from which in vivo and definitive test regimens can be developed. Preliminary in vitro screening of candidate fungicides reduces the need for costly in vivo tests on compounds that have low antifungal activity.

Antibiosis of Trichoderma spp strains native to northeastern Mexico against the pathogenic fungus Macrophomina phaseolina

PubMed Central

Mendoza, José Luis Hernández; Pérez, María Isabel Sánchez; Prieto, Juan Manuel González; Velásquez, Jesús DiCarlo Quiroz; Olivares, Jesús Gerardo García; Langarica, Homar Rene Gill

2015-01-01

Abstract Sampling of agricultural soils from the Mexican northeastern region was performed to detect Trichoderma spp., genetically characterize it, and assess its potential use as a biologic control agent against Macrophomina phaseolina. M. phaseolina is a phytopathogen that attacks over 500 species of cultivated plants and causes heavy losses in the regional sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an area that was approximately 170 km from the Mexico-USA border. Sixteen isolates were obtained in total. Using colony morphology and sequencing the internal transcribed spacers (ITS) 1 and 4 of 18S rDNA, 14 strains were identified as Trichoderma harzianum, T. koningiopsis and T. virens. Subsequently, their antagonistic activity against M. phaseolina was evaluated in vitro, and 11 isolates showed antagonism by competition and stopped M. phaseolina growth. In 4 of these isolates, the antibiosis phenomenon was observed through the formation of an intermediate band without growth between colonies. One strain, HTE808, was identified as Trichoderma koningiopsis and grew rapidly; when it came into contact with the M. phaseolina colony, it continued to grow and sporulated until it covered the entire petri dish. Microscopic examination confirmed that it has a high level of hyperparasitism and is thus considered to have high potential for use in the control of this phytopathogen. PMID:26691467

Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

NASA Astrophysics Data System (ADS)

Matsuura, Kenji; Yashiro, Toshihisa

2006-10-01

Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

Color variation assay of the anthocyanins from Açai Fruit (Euterpe oleracea): a potential new dye for vitreoretinal surgery.

PubMed

Peris, Cristiane Siqueira; Badaro, Emmerson; Ferreira, Magno Antonio; Lima-Filho, Acácio Alves Souza; Ferreira, Eber Lopes; Maia, Andre; Rodrigues, Eduardo Buchele; Farah, Michel Eid; Maia, Maurício

2013-10-01

The goals of this study were to determine the potential for use of the natural anthocyanins from the açai fruit (Euterpe oleracea) during vitreoretinal surgery and the ideal physicochemical properties of the dye. We evaluated the color variations of the dye at different pHs and osmolarities with or without the use of mordants as a potential new tool for internal limiting membrane peeling. The extracts of anthocyanin from the açai fruit were analyzed by spectrophotometry to determine the degree of color variations associated with various pHs and osmolarities. The experiments were conducted in test tubes filled with tryptophan soya media and Petri dishes prepared with agar media. We observed various shades of green, red, and purple in the extracts of the anthocyanin dye at different pHs and osmolarities. The assay to adjust the anthocyanin solution similar to the physiologic retinal environment (osmolarity, 300 mOsm; pH, 7.00) resulted in a shade of purple that may be useful to stain the intraocular microstructures during vitreoretinal surgery. The physicochemical property of the purple anthocyanin solutions from the açai fruit was observed at physiologic pH and osmolarity. Anthocyanins from the açai fruit may be useful to enhance visualization of the intraocular microstructures during vitreoretinal surgery.