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Articles 1 - 6 of 6
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Novel Small Rnas Expressed By Bartonella Bacilliformis Under Multiple Conditions Reveal Potential Mechanisms For Persistence In The Sand Fly Vector And Human Host, Shaun Wachter, Linda D. Hicks, Rahul Raghavan, Michael F. Minnick
Novel Small Rnas Expressed By Bartonella Bacilliformis Under Multiple Conditions Reveal Potential Mechanisms For Persistence In The Sand Fly Vector And Human Host, Shaun Wachter, Linda D. Hicks, Rahul Raghavan, Michael F. Minnick
Biological Sciences Faculty Publications
Bartonella bacilliformis, the etiological agent of Carrión's disease, is a Gram-negative, facultative intracellular alphaproteobacterium. Carrión's disease is an emerging but neglected tropical illness endemic to Peru, Colombia, and Ecuador. B. bacilliformis is spread between humans through the bite of female phlebotomine sand flies. As a result, the pathogen encounters significant and repeated environmental shifts during its life cycle, including changes in pH and temperature. In most bacteria, small non-coding RNAs (sRNAs) serve as effectors that may post-transcriptionally regulate the stress response to such changes. However, sRNAs have not been characterized in B. bacilliformis, to date. We therefore performed total RNA-sequencing …
Matrices (Re)Loaded: Durability, Viability, And Fermentative Capacity Of Yeast Encapsulated In Beads Of Different Composition During Long-Term Fed-Batch Culture, Jordan Gulli, Peter Yunker, Frank Rosenzweig
Matrices (Re)Loaded: Durability, Viability, And Fermentative Capacity Of Yeast Encapsulated In Beads Of Different Composition During Long-Term Fed-Batch Culture, Jordan Gulli, Peter Yunker, Frank Rosenzweig
Biological Sciences Faculty Publications
Encapsulated microbes have been used for decades to produce commodities ranging from methyl ketone to beer. Encapsulated cells undergo limited replication, which enables them to more efficiently convert substrate to product than planktonic cells and which contributes to their stress resistance. To determine how encapsulated yeast supports long-term, repeated fed-batch ethanologenic fermentation, and whether different matrices influence that process, fermentation and indicators of matrix durability and cell viability were monitored in high-dextrose, fed-batch culture over 7 weeks. At most timepoints, ethanol yield (g/g) in encapsulated cultures exceeded that in planktonic cultures. And frequently, ethanol yield differed among the four matrices …
Human Vascular Endothelial Cells Express Epithelial Growth Factor In Response To Infection By Bartonella Bacilliformis, Linda D. Hicks, Michael F. Minnick
Human Vascular Endothelial Cells Express Epithelial Growth Factor In Response To Infection By Bartonella Bacilliformis, Linda D. Hicks, Michael F. Minnick
Biological Sciences Faculty Publications
Bartonella are Gram-negative bacterial pathogens that trigger pathological angiogenesis during infection of humans. Bartonella bacilliformis (Bb) is a neglected tropical agent endemic to South America, where it causes Carrión's disease. Little is known about Bb's virulence determinants or how the pathogen elicits hyperproliferation of the vasculature, culminating in Peruvian warts (verruga peruana) of the skin. In this study, we determined that active infection of human umbilical vein endothelial cells (HUVECs) by live Bb induced host cell secretion of epidermal growth factor (EGF) using ELISA. Killed bacteria or lysates of various Bb strains did not cause EGF production, suggesting that an …
Structure Of The G Protein Chaperone And Guanine Nucleotide Exchange Factor Ric-8a Bound To Gαi1, Levi J. Mcclelland, Kaiming Zhang, Tung-Chung Mou, Jake Johnston, Cindee Yates-Hansen, Shanshan Li, Celestine J. Thomas, Tzanko I. Doukov, Sarah Triest, Alexandre Wohlkonig, Gregory G. Tall, Jan Steyaert, Wah Chiu, Stephen Sprang
Structure Of The G Protein Chaperone And Guanine Nucleotide Exchange Factor Ric-8a Bound To Gαi1, Levi J. Mcclelland, Kaiming Zhang, Tung-Chung Mou, Jake Johnston, Cindee Yates-Hansen, Shanshan Li, Celestine J. Thomas, Tzanko I. Doukov, Sarah Triest, Alexandre Wohlkonig, Gregory G. Tall, Jan Steyaert, Wah Chiu, Stephen Sprang
Biological Sciences Faculty Publications
Ric-8A is a cytosolic Guanine Nucleotide exchange Factor (GEF) that activates heterotrimeric G protein alpha subunits (Gα) and serves as an essential Gα chaperone. Mechanisms by which Ric-8A catalyzes these activities, which are stimulated by Casein Kinase II phosphorylation, are unknown. We report the structure of the nanobody-stabilized complex of nucleotide-free Gα bound to phosphorylated Ric-8A at near atomic resolution by cryo-electron microscopy and X-ray crystallography. The mechanism of Ric-8A GEF activity differs considerably from that employed by G protein-coupled receptors at the plasma membrane. Ric-8A engages a specific conformation of Gα at multiple interfaces to form a complex that …
Encapsulation Enhances Protoplast Fusant Stability, Jordan Gulli, Eugene Kroll, Frank Rosenzweig
Encapsulation Enhances Protoplast Fusant Stability, Jordan Gulli, Eugene Kroll, Frank Rosenzweig
Biological Sciences Faculty Publications
A barrier to cost-efficient biomanufacturing is the instability of engineered genetic elements, such as plasmids. Instability can also manifest at the whole-genome level, when fungal dikaryons revert to parental species due to nuclear segregation during cell division. Here, we show that by encapsulating Saccharomyces cerevisiae-Pichia stipitis dikaryons in an alginate matrix, we can limit cell division and preserve their expanded metabolic capabilities. As a proxy to cellulosic ethanol production, we tested the capacity of such cells to carry out ethanologenic fermentation of glucose and xylose, examining substrate use, ploidy, and cell viability in relation to planktonic fusants, as well as …
Gene Duplication And Deletion, Not Horizontal Transfer, Drove Intra-Species Mosaicism Of Bartonella Henselae, Rachana Banerjee, Oshina Shine, Vyshakh Rajachandran, Govind Krishnadas, Michael F. Minnick, Sandip Paul, Sujay Chattopadhyay
Gene Duplication And Deletion, Not Horizontal Transfer, Drove Intra-Species Mosaicism Of Bartonella Henselae, Rachana Banerjee, Oshina Shine, Vyshakh Rajachandran, Govind Krishnadas, Michael F. Minnick, Sandip Paul, Sujay Chattopadhyay
Biological Sciences Faculty Publications
Bartonella henselae is a facultative intracellular pathogen that occurs worldwide and is responsible primarily for cat-scratch disease in young people and bacillary angiomatosis in immunocompromised patients. The principal source of genome-level diversity that contributes to B. henselae's host-adaptive features is thought to be horizontal gene transfer events. However, our analyses did not reveal the acquisition of horizontally-transferred islands in B. henselae after its divergence from other Bartonella. Rather, diversity in gene content and genome size was apparently acquired through two alternative mechanisms, including deletion and, more predominantly, duplication of genes. Interestingly, a majority of these events occurred in regions that …