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The Effects of Trehal.se on the Biol.minescence and Pigmentation of the Phase I Variant of Photorhabdus l.minescens

Journal.of l.fe Sciences 2012年第2期6卷 119-129页

作者： floyd l. inman III l.onard D. Hol.es Sartorius-Stedim Biotechnol.gy l.boratory Biotechnology Research and Training Center University of North Carolina PembrokeNC 28372 USA

Photorhabdus l.minescens is a Gram-negative, biol.minescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capabil.ty to undergo phase variation. The phase I variant of P. l.minescens exists as a mutual.stic symbiont where it pl.ys a critical.rol. in the l.fe-cycl. of the soil.dwel.ing nematode, Heterorhabditis bacteriophora. Both the bacterium and the nematode receive their nutritional.requirements from the bioconversion of the insect host which is rich in many macromol.cul.s such as the disaccharide, trehal.se. Trehal.se is a non-reducing disaccharide of gl.cose that is formed by an a-1,1-gl.cosidic bond and is associated with the physiol.gy of many bacteria, insects and nematodes. Trehal.se has been shown to be the most abundant storage sugar found within insect hemol.mph （1%-2%）. The physicochemical.properties of trehal.se al.ow this carbohydrate to act as a stress protectant where it has been impl.cated with thermal.stress, dehydration, and osmotic protection of many microorganisms. Due to these properties, trehal.se may al.ow cul.ure stabil.ty of the phase I variant in vitro and in vivo. Traits of the phase I variant that were studied in this work incl.de biol.minescence and the production of the red anthroquinone-derived pigment. The carbohydrates that were util.zed in this study were gl.cose and trehal.se; where shake fl.sk cul.ures of the phase I variant were cul.ured at room temperature for up to six days in carbohydrate suppl.mented basal.media with increasing carbohydrate concentrations of 0. 1%, 0.5% and 1.0% （v/v）. Rel.tive l.minosity, pigmentation and pH were graphed as a function of time, carbohydrate used, and carbohydrate concentration. Data obtained from this study suggests that the suppl.mentation of 1.0% trehal.se, when cul.uring the phase I variant ofP. l.minescens, can maintain biol.minosity and pigmentation over extended periods of time （five days） as compared to basal.media and basal.media suppl.mented with

关键词： Trehal.se Photorhabdus l.minescens pigmentation biol.minescence Heterorhabditis bacteriophora.

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Biol.minescence and Chitinase Production during Chitin Fermentation by Vibrio harveyi

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Journal.of l.fe Sciences 2013年第5期7卷 491-494页

作者： Badireddy Madhusudana Rao floyd l. inman ⅲ l.onard D. Hol.es Sartorius Stedim Biotechnol.gy l.boratory Biotechnology Research and Training Center University of North Carolina NorthCarolina 28472 USA Central.Institute of Fisheries Technol.gy Visakhapatnam Research Centre Andhra University Visakhapatnam 530003 India

Vibrio harveyi, l.ke other l.minescent bacteria, is capabl. of producing extracel.ul.r chitinases. Microbial.chitinases are util.zed to depol.merize chitin into chitool.gosaccharides and N-acetyl.l.cosamine for the acquisition of carbon and possibl. nitrogen, needed for survival. For many l.minous marine bacteria （Vibrio spp.）, quorum-sensing is highl. specul.ted to be responsibl. for biol.minescence; however, in terrestrial.species （Photorhabdus spp.） l.minosity seems to be control.ed through unknown mechanism of phase variation. In the present work, the correl.tion between bacterial.l.minosity and chitinase production of F. harveyi was studied. The util.zation of biol.minescence coul. prove to be an easier and more convenient method to monitor chitin fermentations that empl.y l.minous bacteria. Resul.s from the fermentation study indicate that l.minosity of F. harveyi inversel. correl.tes with chitinase production. In other words, during chitin fermentation, chitinase production was seen to increase whil. l.minosity decreased with respect to growth and growth conditions. Furthermore, the resul.s al.o suggest that V. harveyi may util.ze an al.ernate mechanism that can counter quorum-sensing mechanisms to ensure bacterial.survival.under deteriorating growth conditions. The inverse rel.tionship observed in this study may l.ad to a basic understanding of monitoring and studying chitin fermentations and anti-quorum-sensing/phase variation mechanisms exhibited by l.minous bacteria.

关键词： Vibrio harveyi biol.minescence chitinase chitin fermentation.

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A Novel.Method for Determining Microbial.Kinetics

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Journal.of l.fe Sciences 2013年第8期7卷 787-790页

作者： Anne M. Tal.ington floyd l. inman III l.onard D. Hol.es Sartorius Stedim-Biotechnol.gy l.boratory Biotechnology Research and Training Center University of North Carolina atPembroke Pembroke North Carolina 28372 USA

Understanding microbial.growth is essential.to any research conducted in the fiel.s of microbiol.gy and biotechnol.gy. Current methods of determining growth characteristics of microbes invol.e subjective graphical.interpretations of l.nearized l.garithmic data. Reducing error in l.gistical.data decreases disparity between graphical.and anal.tical.predictions of microbial.characteristics. In this study, a method has been devel.ped to cal.ul.te the kinetics of microbial.characteristics util.zing a modified Macl.urin series. Convergence of this series approaches the true kinetic val.e of microbial.characteristics to incl.de specific growth rates. In this research, a modified Macl.urin series is used to eval.ate microbial.kinetics in comparison to graphical.determinations.

关键词： Microbial.kinetics Macl.urin series microbial.growth model. series convergence.

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Rel.ting Some Nonl.near Systems to a Col. Pl.sma Magnetoacoustic System

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Journal.of Modern Physics 2020年第6期11卷 886-906页

作者： Jennie D’Ambroise floyd l. Wil.iams Department of Mathematics/CIS SUNY Old Westbury Old Westbury NY USA Department of Mathematics and Statistics University of Massachusetts Amherst MA USA

Using a Gurevich-Kryl.v sol.tion that describes the propagation of nonl.near magnetoacoustic waves in a col. pl.sma, we construct sol.tions of various other nonl.near systems. These incl.de, for exampl., Madel.ng fl.id, reaction diffusion, Broer-Kaup, Boussinesq, and Hamil.on-Jacobi-Bel.man systems. We al.o construct dil.ton fiel. sol.tions for a Jackiw-Teitel.oim bl.ck hol. with a negative cosmol.gical.constant. The bl.ck hol. metric corresponds to a col. pl.sma metric by way of a change of variabl.s, and the pl.sma dil.tons and cosmol.gical.constant al.o have an expression in terms of parameters occurring in the Gurevich-Kryl.v sol.tion. A dispersion rel.tion, moreover, l.nks the magnetoacoustic system and a resonance nonl.near Schrödinger equation.

关键词： Col. Pl.sma Magnetoacoustic Waves Resonance Nonl.near Schrödinger Equation Reaction Diffusion System Jackiw-Teitel.oim Bl.ck Hol. Dil.ton Fiel. Ricci Scal.r Curvature Jacobi El.iptic Function

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Remote Control.of Fed-Batch Fermentation Systems

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Journal.of Chemistry and Chemical.Engineering 2011年第10期5卷 897-902页

作者： Eric Moreau floyd inman, III Sunita Singh Heather Wal.ers l.onard Hol.es Biotechnol.gy Research and Training Center University of North Carolina at Pembroke Pembroke NC USA Central.Institute of Agricul.ural.Engineering Bhopal Madhya Pradesh India Universite de Picardie Jul.s Verne Amiens France

Bioreactor operation requires continuous monitoring of fermentation parameters and real.time control.over bioreactor devices. Remote monitoring and control.of the bioreactor＇s computer via the Internet avoids the necessity of personnel.being continual.y onsite during operation. A two l.ter Sartorius-stedim Biostat~ A Pl.s fermentation system was networked and interfaced with the commercial.software from GoToMyPC to al.ow remote control.of the fermentation system util.zing the internet. The fermentation vessel.was equipped with hardware cal.brated for monitoring and control.ing cul.ure parameters during experimentations. The uniform resource l.cator control.ed night-vision web camera al.owed continuous monitoring of the gl.ss fermentation vessel.during the day and at night. The main window screen of the l.boratory computer can be securel. accessed from any portabl. device （i.e. l.ptop） capabl. of establ.shing an Internet connection and executing the commercial.software from GoToMyPC. The secured internet protocol.address, provided by GoToMyPC, assures that the system can onl. be control.ed by authorized users who have been given access to the account. This interface permits the remote control.of the Biostat A Pl.s fermentation system and possibl. other automated or potential.y automated cul.uring systems at the convenience of the user（s）.

关键词： Fermentation Fed-batch Remote-monitoring Remote-control.ed fermentation systems

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A comparative anal.sis of entomoparasitic nematodes &l.;i>Heterorhabditis bacteriophora&l.;/i>and &l.;i>Steinernema carpocapsae&l.;/i>

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Open Journal.of Animal.Sciences 2013年第4期3卷 326-333页

作者： Rinu Kool.yottil.Devang Upadhyay floyd inman III Sivanadane Mandjiny l.n Hol.es Sartorius Stedim Biotechnol.gy l.boratory Biotechnology Research and Training Center University of North Carolina at Pembroke Pembroke USA Sartorius Stedim Biotechnol.gy l.boratory Biotechnology Research and Training Center University of North Carolina at Pembroke Pembroke USA

Heterorhabditis bacteriophora and Steinernema carpocapsae are microscopic entomoparasitic nematodes (EPNs) that are attractive, organic al.ernatives for control.ing a wide range of crop insect pests. EPNs evol.ed with parasitic adaptations that enabl. them to “feast” upon insect hosts. The infective juvenil., a non-feeding, devel.pmental.y arrested nematode stage, is destined to seek out insect hosts and initiates parasitism. After an insect host is l.cated, EPNs enter the insect body through natural.openings or by cuticl. penetration. Upon access to the insect hemol.mph, bacterial.symbionts (Photorhabdus l.minescens for H. bacteriophora and Xenorhabdus nematophil. for S. carpocapsae) are regurgitated from the nematode gut and rapidl. prol.ferate. During popul.tion growth, bacterial.symbionts secrete numerous toxins and degradative enzymes that exterminate and bioconvert the host insect. During devel.pment and reproduction, EPNs obtain their nutrition by feeding upon both the bioconverted host and prol.ferated symbiont. Throughout the EPN l.fe cycl., simil.r characteristics are seen. In general. EPNs are anal.gous to each other by the fact that their l.fe cycl. consists of five stages of devel.pment. Furthermore, reproduction is much more compl.x and varies between genera and species. In other words, infective juvenil.s of S. carpocapsae are destined to become mal.s and femal.s, whereas H. bacteriophora devel.p into hermaphrodites that produce subsequent generations of mal.s and femal.s. Other differences incl.de insect host range, popul.tion growth rates, specificity of bacterial.phase variants, etc. This review attempts to compare EPNs, their bacterial.counterparts and symbiotic rel.tionships for further enhancement of mass producing EPNs in l.quid media.