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Yersinia enterocolitica is typically considered an extracellular pathogen; however, during the course of an infection, a significant number of bacteria are stably maintained within host cell vacuoles. Little is known about this population and the role it plays during an infection. To address this question and to elucidate the spatially and temporally dynamic gene expression patterns of Y. enterocoliticabiovar 1B through the course of an in vitro infection, transcriptome sequencing and differential gene expression analysis of bacteria infecting murine macrophage cells were performed under four distinct conditions. Bacteria were first grown in a nutrient-rich medium at 26°C to establish a baseline of gene expression that is unrelated to infection. The transcriptomes of these bacteria were then compared to bacteria grown in a conditioned cell culture medium at 37°C to identify genes that were differentially expressed in response to the increased temperature and medium but not in response to host cells. Infections were then performed, and the transcriptomes of bacteria found on the extracellular surface and intracellular compartments were analyzed individually. The upregulated genes revealed potential roles for a variety of systems in promoting intracellular virulence, including the Ysa type III secretion system, the Yts2 type II secretion system, and the Tad pilus. It was further determined that mutants of each of these systems had decreased virulence while infecting macrophages. Overall, these results reveal the complete set of genes expressed by Y. enterocolitica in response to infection and provide the groundwork for future virulence studies.

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TYPE Journal Article YEAR 2015

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Enhanced vector borne disease surveillance of California Culex mosquito populations reveals spatial and species-specific barriers of infection

VanderNoot, Victoria A.; Curtis, Deanna J.; Koh, Chung-Yan K.; Brodsky, Benjamin H.; Lane, Todd L.

Monitor i ng in f ectio n s in v ect o rs su c h as m osquit o es, s a nd fl i es, tsetse fl i es, a nd ticks to i denti f y hu m a n path o gens m a y s e r v e as a n ear l y w arn i ng det e ction system t o dir e ct loc a l g o v er n ment dise a se pr e v en t i v e m easu r e s . One major hurdle i n de t ection is the abi l i t y to scre e n l arge n u mbers of v e c t ors for h uman patho g ens w i thout t h e u s e of ge n o t y pe - s p ecific m o lecu l ar tec h nique s . N e x t genera t ion s equ e nc i ng (NG S ) pr o v i des a n unbi a sed p latfo r m capab l e of identi f y i ng k n o w n a n d unk n o w n p ath o ge n s circula t ing w i thin a v e ctor p opul a tion, but utili z ing t h is te c h nolo g y i s tim e - con s u ming a n d cos t l y for v ecto r -b o rne disease su r v e illan c e pr o gra m s. T o addr e s s this w e d e v e lop e d cos t -eff e ct i v e Ilumina(r) R NA- S eq l i bra r y p r epara t ion m e thodol o gies i n con j u n ction w i t h an automa t ed c ompu t at i onal a n a l y sis pipel i n e to ch a racter i ze t h e microbial popula t ions c ircula t i n g in Cu l e x m o squit o e s (Cul e x qui n quef a s c iatu s , C ul e x quinq u efasc i atus / pip i ens co m pl e x h y bri d s, and C u l e x ta r salis ) t hroug h out Californ i a. W e assembled 2 0 n o vel a n d w e l l -do c ume n ted a r b o v i ruses repres e nting mem b e rs of B u n y a v ir i da e , F l a v i virid a e, If a virida e , Meson i v i rida e , Nid o v iri d ae, O rtho m y x o virid a e, Pa r v o v iri d ae, Re o virid a e, R h a b d o v i rid a e, T y m o v iri d ae, a s w ell as s e v e r al u n assi g n e d v irus e s . In addit i o n, w e m app e d mRNA s pecies to d i vergent s peci e s of t r y panos o ma a nd pl a s modium eu k a r yotic parasit e s and cha r a c terized t he p r oka r yot i c microb i al c o mposit i on to i d enti f y bacteri a l tran s c r ipts der i v ed from wolba c hia, clo s tridi u m, m y c oplas m a, fusoba c terium and c am p y l o bacter bac t er i al spec i e s . W e utilized the s e mic r obial transcri p tomes pre s e nt in g e ogra p hical l y defined Cul e x po p ul a tions to defi n e spatial and m osqui t o specie s -spec i fic ba r r iers of i n fecti o n. T he v i r ome and microbi o me c o mpos i tion id e ntified in e ach mosqui t o p o ol pr o v i ded suf f icient resolut i on to dete r m i ne both the mosq u ito species and the g e o graphic regi o n in Californ i a w h e re t h e mosqui t o po o l orig i n ated. T his d a ta pr o v i des ins i ght in t o the compl e x i t y of microb i al spec i es cir c ulati n g in med i cal l y i mport a nt Culex mosqui t oes a nd t h eir potent i al im p act o n t he tran s missi o n of v ector-b o rne human / veter i na r y p a t hogens in C a liforn i a.

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TYPE SAND Report YEAR 2014

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