Latest Publications
Complement-mediated killing of Escherichia coli by mechanical destabilization of the cell envelope
Georgina Benn, Christian Bortolini, David M Roberts, Alice L B Pyne, Seamus Holden, Bart W Hoogenboom
Complement proteins eliminate Gram-negative bacteria in the blood via the formation of membrane attack complex (MAC) pores in the outer membrane. However, it remains unclear how outer membrane poration leads to inner membrane permeation and cell lysis. Using atomic force microscopy (AFM) on living Escherichia coli (E. coli), we probed MAC-induced changes in the cell envelope and correlated these with subsequent cell death. We conclude that bacterial cell lysis is only an indirect effect of MAC formation; outer membrane poration leads to mechanical destabilization of the cell envelope, reducing its ability to contain the turgor pressure, leading to inner membrane permeation and cell death.
Comparative genomics and transcriptomics reveal differences in effector complement and expression between races of Fusarium oxysporum f.sp. lactucae
Helen J. Bates, Jamie Pike, R. Jordan Price, Sascha Jenkins, John Connell, Andrew Legg, Andrew Armitage, Richard J. Harrison and John P. Clarkson
This study presents the first genome and transcriptome analyses for Fusarium oxysporum f. sp. lactucae (Fola) which causes Fusarium wilt disease of lettuce. Long-read genome sequencing of three race 1 (Fola1) and three race 4 (Fola4) isolates revealed key differences in putative effector complement between races and with other F. oxysporum ff. spp. following mimp-based bioinformatic analyses.
Early Steps of the Biosynthesis of the Anticancer Antibiotic Pleurotin
Jack A. Weaver, Duha Alkhder, Panward Prasongpholchai, Michaël D. Tadesse, Emmanuel L. de los Santos, Lijiang Song, Christophe Corre, Fabrizio Alberti
Pleurotin is a meroterpenoid specialized metabolite made by the fungus Hohenbuehelia grisea, and it is a lead anticancer molecule due to its irreversible inhibition of the thioredoxin-thioredoxin reductase system. Total synthesis of pleurotin has been achieved, including through a stereoselective route; however, its biosynthesis has not been characterized. In this study, we used isotope-labeled precursor feeding to show that the nonterpenoid quinone ring of pleurotin and its congeners is derived from phenylalanine. This work sets the foundation to fully elucidate the biosynthesis of pleurotin and its congeners, with long-term potential to optimize their production for therapeutic use and engineer the pathway toward the biosynthesis of valuable analogues.
Imaging Glucose Metabolism and Dopaminergic Dysfunction in Sheep (Ovis aries) Brain using PET Imaging Reveals Abnormalities in OVT73 Huntington’s Disease Sheep
Williams G.K., Akkermans J., Lawson M., Syta P., Staelens S., Adhikari M.H., Morton A.J., Nitzsche B., Boltze J., Christou C., Bertoglio D., Ahamed M.
The major goal of our preliminary cross-sectional study is to demonstrate the feasibility and utility of the unique transgenic sheep model of HD (OVT73) in positron emission tomography (PET) imaging. In this first-of-its-kind study, we showed the usefulness and validity of HD sheep model in imaging cerebral glucose metabolism and dopamine uptake using PET imaging. The identification of discrete patterns of metabolic abnormality using [18F]FDG and decline of [18F]FDOPA uptake may provide a useful means of quantifying early HD-related changes in these models, particularly in the transition from presymptomatic to early symptomatic phases of HD.
A regulatory module mediating temperature control of cell-cell communication facilitates tree bud dormancy release
Shashank K Pandey, Jay Prakash Maurya, Bibek Aryal, Kamil Drynda, Aswin Nair, Pal Miskolczi, Rajesh Kumar Singh, Xiaobin Wang, Yujiao Ma, Tatiana de Souza Moraes, Emmanuelle M Bayer, Etienne Farcot, George W Bassel, Leah R Band, Rishikesh P Bhalerao
The control of cell–cell communication via plasmodesmata (PD) plays a key role in plant development. In tree buds, low-temperature conditions (LT) induce a switch in plasmodesmata from a closed to an open state, which restores cell-to-cell communication in the shoot apex and releases dormancy. Using genetic and cell-biological approaches, we have identified a previously uncharacterized transcription factor, Low-temperature-Induced MADS-box 1 (LIM1), as an LT-induced, direct upstream activator of the gibberellic acid (GA) pathway. Mathematical modeling and experimental validation suggest that negative feedback regulation of LIM1 by gibberellin could play a crucial role in maintaining the robust temporal regulation of bud responses to low temperature. These results reveal genetic factors linking temperature control of cell–cell communication with regulation of seasonally-aligned growth crucial for adaptation of trees.
Ammonia leakage can underpin nitrogen-sharing among soil microorganisms.
Luke Richards, Kelsey Cremin, Mary Coates, Finley Vigor, Patrick Schäfer, and Orkun S Soyer
Soil microbial communities host a large number of microbial species that support important ecological functions such as biogeochemical cycling and plant nutrition. The extent and stability of these functions are affected by inter-species interactions among soil microorganisms, yet the different mechanisms underpinning microbial interactions in the soil are not fully understood. Here, we study the extent of nutrient-based interactions among two model, plant-supporting soil microorganisms, the fungi Serendipita indica, and the bacteria Bacillus subtilis. Our findings highlight that ammonia based N-sharing can be a previously under-appreciated mechanism underpinning interaction among soil microorganisms and could be influenced by microbial or abiotic alteration of pH in microenvironments.