Bacteria manipulate salt to build shelters to hibernate

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For the first time, Spanish researchers have detected an unknown interaction between microorganisms and salt. When Escherichia coli cells are introduced into a droplet of salt water that is left to dry, bacteria manipulate the sodium chloride crystallisation to create biomineralogical biosaline 3-D morphologically complex formations, where they hibernate. Afterwards, simply by rehydrating the material, bacteria are revived. The discovery was made by chance with a home microscope, but it made the cover of the ‘Astrobiology’ journal and may help us find signs of life on other planets.The bacterium Escherichia coli is one of the most studied living forms by biologists, but none had to date noticed what this microorganism can do within a simple drop of salt water: create impressive biomineralogical patterns in which it shelters itself when it dries.”It was a complete surprise, a fully unexpected result, when I introduced E.. coli cells into salt water and I realised that the bacteria had the ability to join the salt crystallisation and modulate the development and growth of the sodium chloride crystals,” biologist Jos Mara Gmez said.”Thus, in around four hours, in the drop of water that had dried, an impressive tapestry of biosaline patterns was created with complex 3D architecture,” added the researcher, who made the discovery with the microscope in his house, although he later confirmed it with the help of his colleagues from the Laboratory of BioMineralogy and Astrobiological Research (LBMARS, University of Valladolid-CSIC), Spain.Until present, we knew of similar patterns created from saline solutions and isolated proteins, but this is the first report that demonstrates how whole bacterial cells can manage the crystallisation of sodium chloride (NaCl) and generate self-organised biosaline structures of a fractal or dendritic appearance. The study and the striking three-dimensional patterns are on the front cover of this month’s edition of Astrobiology.”The most interesting result is that the bacteria enter a state of hibernation inside these desiccated patterns, but they can later be ‘revived’ simply by rehydration,” said Gmez, who highlighted a very important result from an astrobiological point of view: “Given the richness and complexity of these formations, they may be used as biosignatures in the search for life in extremely dry environments outside our own planet, such as the surface of Mars or that of Jupiter’s satellite, Europa.”In fact, the LBMARS laboratory participates in the development of the Raman RLS instrument of the ExoMars rover, the mission that the European Space Agency (ESA) will send to the red planet in 2018, and this new finding may help them search for possible biological signs. According to the researcher, “the patterns observed will help calibrate the instrument and test its detection of signs of hibernation or traces of Martian life.””The challenge we now face is to understand how the bacteria control the crystallisation of NaCl to create these incredible 3D structures and vice-versa, how salt influences this action, as well as studying the structure of these microorganisms that withstand desiccation,” said Gmez, who reminds us that a simple curiosity and excitement about science, although it may be with simple means, still allows us to make some interesting discoveries: “This is a tribute to scientists such as the Spaniard Santiago Ramn y Cajal and the Dutch scientist Anton van Leeuwenhoek, who also worked from home with their own microscopes”Story Source:The above story is based on materials provided by Plataforma SINC. Note: Materials may be edited for content and length.


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Experiences at every stage of life contribute to cognitive abilities in old age

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Early life experiences, such as childhood socioeconomic status and literacy, may have greater influence on the risk of cognitive impairment late in life than such demographic characteristics as race and ethnicity, a large study by researchers with the UC Davis Alzheimer’s Disease Center and the University of Victoria, Canada, has found.”Declining cognitive function in older adults is a major personal and public health concern,” said Bruce Reed professor of neurology and associate director of the UC Davis Alzheimer’s Disease Center.”But not all people lose cognitive function, and understanding the remarkable variability in cognitive trajectories as people age is of critical importance for prevention, treatment and planning to promote successful cognitive aging and minimize problems associated with cognitive decline.”The study, “Life Experiences and Demographic Influences on Cognitive Function in Older Adults,” is published online in Neuropsychology, a journal of the American Psychological Association. It is one of the first comprehensive examinations of the multiple influences of varied demographic factors early in life and their relationship to cognitive aging.The research was conducted in a group of over 300 diverse men and women who spoke either English or Spanish. They were recruited from senior citizen social, recreational and residential centers, as well as churches and health-care settings. At the time of recruitment, all study participants were 60 or older, and had no major psychiatric illnesses or life threatening medical illnesses. Participants were Caucasian, African-American or Hispanic.The extensive testing included multidisciplinary diagnostic evaluations through the UC Davis Alzheimer’s Disease Center in either English or Spanish, which permitted comparisons across a diverse cohort of participants.Consistent with previous research, the study found that non-Latino Caucasians scored 20 to 25 percent higher on tests of semantic memory (general knowledge) and 13 to 15 percent higher on tests of executive functioning compared to the other ethnic groups. However, ethnic differences in executive functioning disappeared and differences in semantic memory were reduced by 20 to 30 percent when group differences in childhood socioeconomic status, adult literacy and extent of physical activity during adulthood were considered.”This study is unusual in that it examines how many different life experiences affect cognitive decline in late life,” said Dan Mungas, professor of neurology and associate director of the UC Davis Alzheimer’s Disease Research Center.”It shows that variables like ethnicity and years of education that influence cognitive test scores in a single evaluation are not associated with rate of cognitive decline, but that specific life experiences like level of reading attainment and intellectually stimulating activities are predictive of the rate of late-life cognitive decline. This suggests that intellectual stimulation throughout the life span can reduce cognitive decline in old age.”Regardless of ethnicity, advanced age and apolipoprotein-E (APOE genotype) were associated with increased cognitive decline over an average of four years that participants were followed. APOE is the largest known genetic risk factor for late-onset Alzheimer’s. Less decline was experienced by persons who reported more engagement in recreational activities in late life and who maintained their levels of activity engagement from middle age to old age. Single-word reading — the ability to decode a word on sight, which often is considered an indication of quality of educational experience — was also associated with less cognitive decline, a finding that was true for both English and Spanish readers, irrespective of their race or ethnicity. …


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