Water is the fundamental molecule for life on Earth. Thus, the search for hibernating life-forms in waterless environments is an important research topic for astrobiology. To date, however, the organizational patterns containing microbial life in extremely dry places, such as the deserts of Earth, the Dry Valleys of Antarctica, or Mars analog regolith, have been poorly characterized. Here, we report on the formation of bacterial biosaline self-organized drying patterns formed over plastic surfaces. These emerge during the evaporation of sessile droplets of aqueous NaCl salt 0.15 M solutions containing Escherichia coli cells. In the present study, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) analyses indicated that the bacterial cells and the NaCl in these biosaline formations are organized in a two-layered characteristic 3-D architectural morphology. A thin filmlike top layer formed by NaCl conjugated to, and intermingled with, "mineralized" bacterial cells covers a bottom layer constructed by the bulk of the nonmineralized bacterial cells; both layers have the same morphological pattern. In addition, optical microscopic time-lapsed movies show that the formation of these patterns is a kinetically fast process that requires the coupled interaction between the salt and the bacterial cells. Apparently, this mutual interaction drives the generative process of self-assembly that underlies the drying pattern formation. Most notably, the bacterial cells inside these drying self-assembled patterns enter into a quiescent suspended anhydrobiotic state resistant to complete desiccation and capable of vital reanimation upon rehydration. We propose that these E. coli biosaline drying patterns represent an excellent experimental model for understanding different aspects of anhydrobiosis phenomena in bacteria as well as for revealing the mechanisms of bacterially induced biomineralization, both highly relevant topics for the search of life in extraterrestrial locations.
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http://dx.doi.org/10.1089/ast.2014.1162 | DOI Listing |
Immunol Rev
December 2024
Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Innate immune cells perform vital tasks in detecting, seeking, and eliminating invading pathogens, thus ensuring host survival. However, loss of function of these cells or their overactive response to tissue injury often causes serious ailments. It is, therefore, crucial to understand at a basic level how these cells function in health and disease.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
Gram-negative bacteria can use the type III secretion system (T3SS) to inject effector proteins into eukaryotic target cells. In this chapter, we describe the application of a light-controlled T3SS, based on the targeted sequestration of an essential dynamic T3SS component with the help of optogenetic interaction switches. This method enables to control the secretion or injection into eukaryotic cells for a wide range of protein cargos with high temporal and spatial precision.
View Article and Find Full Text PDFCell Rep
December 2024
Department of Microbiology and Immunology, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA. Electronic address:
It is not clear how CD4 memory T cells are formed from a much larger pool of earlier effector cells. We found that transient systemic bacterial infection rapidly generates several antigen-specific T helper (Th)1 and T follicular helper (Tfh) cell populations with different tissue residence behaviors. Although most cells of all varieties had transcriptomes indicative of cell stress and death at the peak of the response, some had already acquired a memory cell signature characterized by expression of genes involved in cell survival.
View Article and Find Full Text PDFSmall
December 2024
School of Chemical Engineering, Sichuan University, No 24th, South Section 1, Yihuan Road, Chengdu, Sichuan, 610065, China.
The exogenous bacterial infection and formation of biofilm on the surface of titanium implants can affect the adhesion, proliferation, and differentiation of cells associated with osteogenesis, ultimately leading to surgical failure. This study focuses on two critical stages for biofilm formation: i) bacterial adhesion and aggregation, ii) growth and proliferation. The titanium with well-organized titania nanotube arrays is first modified by nitrogen dopants, then loaded with CuFeSe nanoparticles to form a p-n heterojunction.
View Article and Find Full Text PDFAdv Healthc Mater
December 2024
School of Materials and Engineering, Ho hai university, Nanjing, 210000, China.
This study explores the potential of DNA hydrogels as a novel approach for diagnosing and treating Oral Squamous Cell Carcinoma (OSCC). In the experiment, DNA hydrogels are synthesized and loaded with Zinc Oxide Nanoparticles (ZnO NPs) and Cisplatin. In vitro experiments evaluated drug delivery efficacy and the effect on cancer cell viability.
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